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17 - GIT/009 Git Branching_en.srt

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+1
+00:00:06,000 --> 00:00:11,000
+Hello, dissidents, today we are going to a very important lesson today will learn what branches and
+
+2
+00:00:11,000 --> 00:00:13,000
+how to ensure smooth navigation between them.
+
+3
+00:00:14,000 --> 00:00:19,000
+I will explain you how comets, asteroids and get in a nutshell will answer the question, what actually
+
+4
+00:00:19,000 --> 00:00:20,000
+branches?
+
+5
+00:00:20,000 --> 00:00:21,000
+I will explain today.
+
+6
+00:00:21,000 --> 00:00:27,000
+What is it that after you will understand, the theory will proceed with practice exercises to learn
+
+7
+00:00:27,000 --> 00:00:33,000
+commands that will allow us to create new branches and navigate between already existing ones.
+
+8
+00:00:33,000 --> 00:00:39,000
+You learn such commands as Check-Out and Gifts, which will Ranjith branch command.
+
+9
+00:00:39,000 --> 00:00:43,000
+And I'll tell you how you can list all your local branches and remote.
+
+10
+00:00:43,000 --> 00:00:49,000
+Once you're in the practice exercises, I'll show you how you can remove branch locally and in remote
+
+11
+00:00:49,000 --> 00:00:52,000
+repository while navigating between the snapshots.
+
+12
+00:00:52,000 --> 00:00:55,000
+I will show you what the touch that state is.
+
+13
+00:00:55,000 --> 00:01:00,000
+Besides that, today I will show you basically next terminal commands for navigation in the file system,
+
+14
+00:01:00,000 --> 00:01:02,000
+creating files and listin files.
+
+15
+00:01:03,000 --> 00:01:08,000
+Lets start and to start with, let's imagine the case that you receive task on your work and you need
+
+16
+00:01:08,000 --> 00:01:11,000
+to implement it to start work on the new task.
+
+17
+00:01:11,000 --> 00:01:16,000
+You have to isolate your changes from the stable version of your code to make sure you will not mess
+
+18
+00:01:16,000 --> 00:01:18,000
+it up through the late hour code.
+
+19
+00:01:18,000 --> 00:01:22,000
+During the development of the new feature that allows us to create a separate branch.
+
+20
+00:01:23,000 --> 00:01:25,000
+What is the branch we briefly discussed?
+
+21
+00:01:25,000 --> 00:01:26,000
+What is the branch one?
+
+22
+00:01:26,000 --> 00:01:28,000
+We talked about our master branch.
+
+23
+00:01:29,000 --> 00:01:35,000
+But let's recap one more time and simple words unit branch to diverge from the main branch to continue
+
+24
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+development without messing with the main development branch.
+
+25
+00:01:38,000 --> 00:01:44,000
+For example, here's the main development branch where the latest version of the code is stored and
+
+26
+00:01:44,000 --> 00:01:46,000
+you want to start work on the new task.
+
+27
+00:01:47,000 --> 00:01:53,000
+You create a separate branch, you create comments on that branch, and after that you merge a branch
+
+28
+00:01:53,000 --> 00:01:55,000
+with the development branch easy.
+
+29
+00:01:55,000 --> 00:02:01,000
+Meanwhile, another developer can create a new branch and work in parallel with you for some period
+
+30
+00:02:01,000 --> 00:02:04,000
+of time and merge his changes with years later.
+
+31
+00:02:05,000 --> 00:02:08,000
+That's why we need branches during the software development in a team.
+
+32
+00:02:09,000 --> 00:02:15,000
+To understand how branches work, we need to understand a bit deeper how get stores information you
+
+33
+00:02:15,000 --> 00:02:18,000
+remember that gets its files as a series of the snapshots.
+
+34
+00:02:18,000 --> 00:02:24,000
+When we create a command, get to commit objects that contains a pointer to the snapshot of the content
+
+35
+00:02:24,000 --> 00:02:26,000
+that we added to the staging area.
+
+36
+00:02:26,000 --> 00:02:32,000
+Also, this object stauss pointers to the comments that directly came before the current commit.
+
+37
+00:02:32,000 --> 00:02:38,000
+Before we start learning specific commands how to create branches, I want you to understand the theory,
+
+38
+00:02:38,000 --> 00:02:44,000
+at least on the high level, how it works, what actually happens when we create a new branch on this
+
+39
+00:02:44,000 --> 00:02:49,000
+slide, you can see that I created a new branch with the name testing what actually happened in the
+
+40
+00:02:49,000 --> 00:02:50,000
+language of it.
+
+41
+00:02:50,000 --> 00:02:56,000
+I just created a new pointer on the current commit on the moment when I create a new branch from the
+
+42
+00:02:56,000 --> 00:03:03,000
+master to pointers are pointing out to the same command, but how it knows that at this specific moment
+
+43
+00:03:03,000 --> 00:03:07,000
+of time I'm on the Master Branch, but not on the testing branch.
+
+44
+00:03:07,000 --> 00:03:08,000
+There is one more point.
+
+45
+00:03:08,000 --> 00:03:09,000
+I called that.
+
+46
+00:03:09,000 --> 00:03:11,000
+Now let's imagine we switched branches.
+
+47
+00:03:12,000 --> 00:03:16,000
+I will show you comments a bit later in this lesson when we will have practice exercise.
+
+48
+00:03:16,000 --> 00:03:23,000
+Right now, I want you to focus on the series and this visualization switch branches in the language
+
+49
+00:03:23,000 --> 00:03:25,000
+object is to change head pointer.
+
+50
+00:03:25,000 --> 00:03:31,000
+Now, Head is pointing out to the testing pointer being on this branch, we can create a new command.
+
+51
+00:03:31,000 --> 00:03:32,000
+What happens next?
+
+52
+00:03:33,000 --> 00:03:38,000
+Our testing branch moved forward while Master Branch still points to the previous command.
+
+53
+00:03:38,000 --> 00:03:44,000
+So in this particular case, if you would switch back to the master branch, you would see the state
+
+54
+00:03:44,000 --> 00:03:46,000
+of the file system, which was before your last commit.
+
+55
+00:03:47,000 --> 00:03:53,000
+OK, now you can imagine how pointers and it works, but let's move further now.
+
+56
+00:03:53,000 --> 00:03:58,000
+Imagine that somebody, some as a developer, managed to put changes into the master branch and then
+
+57
+00:03:58,000 --> 00:04:00,000
+you can meet and Master Branch appeared.
+
+58
+00:04:01,000 --> 00:04:03,000
+Your project history has diverged.
+
+59
+00:04:03,000 --> 00:04:07,000
+Both changes in these two countries are isolated from each other.
+
+60
+00:04:07,000 --> 00:04:08,000
+But we can merge.
+
+61
+00:04:08,000 --> 00:04:13,000
+This changes if we want that this exact scenario which we need to learn together.
+
+62
+00:04:13,000 --> 00:04:18,000
+And this course, we are going to learn how to merge changes together from different branches.
+
+63
+00:04:18,000 --> 00:04:22,000
+So right now, you already understand the theory of branches.
+
+64
+00:04:22,000 --> 00:04:28,000
+You can visualize in your mind how navigation between branches works and why do we need this now it
+
+65
+00:04:28,000 --> 00:04:32,000
+is time to run specific it commands that will allow you to navigate between branches.
+
+66
+00:04:32,000 --> 00:04:35,000
+Let's practice usually on the job.
+
+67
+00:04:35,000 --> 00:04:39,000
+You are going to use some task management system or issue trackers that will give you a unique idea
+
+68
+00:04:39,000 --> 00:04:40,000
+of your task.
+
+69
+00:04:41,000 --> 00:04:46,000
+Imagine that we have a task to implement logic of discount calculation for our customers based on the
+
+70
+00:04:46,000 --> 00:04:52,000
+history of purchases where we need to start, we need to start from creation of the branch.
+
+71
+00:04:52,000 --> 00:04:54,000
+There are different ways to create branches.
+
+72
+00:04:55,000 --> 00:05:02,000
+One of the options is to use the next command, get Branch G a three zero one.
+
+73
+00:05:03,000 --> 00:05:10,000
+Let's press enter new branch is created, but you see here in parentheses, I'm still in the master
+
+74
+00:05:10,000 --> 00:05:13,000
+branch to check which branches I have locally.
+
+75
+00:05:13,000 --> 00:05:19,000
+I have to just use the next command get branch to see all remoted branches.
+
+76
+00:05:19,000 --> 00:05:23,000
+I have to use the next command branch was option are.
+
+77
+00:05:24,000 --> 00:05:29,000
+And you see that right now I have only one branch and remote that is my original Austin branch.
+
+78
+00:05:29,000 --> 00:05:33,000
+To see all local and remote branches you have to use the EH option.
+
+79
+00:05:34,000 --> 00:05:36,000
+Get Branch Desh a.
+
+80
+00:05:37,000 --> 00:05:43,000
+And here we can find all local and remote branches, but to be honest, the branch command is rarely
+
+81
+00:05:43,000 --> 00:05:49,000
+used among developers to create a new branch because this command only creates branch but not get you
+
+82
+00:05:49,000 --> 00:05:50,000
+to the new branch.
+
+83
+00:05:50,000 --> 00:05:55,000
+Usually software engineers use the commands it creates and changed branches simultaneously.
+
+84
+00:05:56,000 --> 00:05:58,000
+So let's type the following year.
+
+85
+00:05:58,000 --> 00:05:59,000
+Check out, check out.
+
+86
+00:05:59,000 --> 00:06:01,000
+Command is for changing branches.
+
+87
+00:06:02,000 --> 00:06:07,000
+Option B, this option is to indicate that I want to change and create a new branch.
+
+88
+00:06:07,000 --> 00:06:17,000
+B stands for Branch and now let's specify the name of the branch task three zero one underscore discount.
+
+89
+00:06:17,000 --> 00:06:19,000
+Underscore calculation.
+
+90
+00:06:19,000 --> 00:06:25,000
+Usually with the task, we would like to specify a brief description of what changes will be in this
+
+91
+00:06:25,000 --> 00:06:26,000
+branch press.
+
+92
+00:06:26,000 --> 00:06:33,000
+Enter and we switch to the new branch and in parentheses you can easily identify on which branch you
+
+93
+00:06:33,000 --> 00:06:36,000
+are right now and where is your head pointer.
+
+94
+00:06:36,000 --> 00:06:38,000
+OK, we created changes.
+
+95
+00:06:38,000 --> 00:06:40,000
+Now let's implement our task.
+
+96
+00:06:41,000 --> 00:06:42,000
+For the sake of example.
+
+97
+00:06:42,000 --> 00:06:49,000
+I won't write any code and I will not implement any logic related to the discount calculation because
+
+98
+00:06:49,000 --> 00:06:51,000
+I want you now to focus only on it.
+
+99
+00:06:52,000 --> 00:06:53,000
+But let's imitate that.
+
+100
+00:06:53,000 --> 00:06:57,000
+We need some changes and all of them stored in the new file.
+
+101
+00:06:57,000 --> 00:07:00,000
+Let me use Linux commands to create a new file.
+
+102
+00:07:00,000 --> 00:07:07,000
+First of all, I want to navigate to the folder with the source code Siggie, SIRC and Presenta.
+
+103
+00:07:08,000 --> 00:07:15,000
+Sydney stands for Change Directory and you see here in the path that I navigated to the SC directory.
+
+104
+00:07:16,000 --> 00:07:22,000
+Dutch discount calculation service, Dutch Java Dutch Command allows us to create file.
+
+105
+00:07:23,000 --> 00:07:28,000
+This is one of the possible ways to create files with Linux terminals to check what files you have in
+
+106
+00:07:28,000 --> 00:07:29,000
+the directory.
+
+107
+00:07:29,000 --> 00:07:31,000
+Let me show you one more Linux command.
+
+108
+00:07:32,000 --> 00:07:35,000
+Alas, Resorption El Al.
+
+109
+00:07:35,000 --> 00:07:39,000
+S is a command that list files in the specific directories.
+
+110
+00:07:39,000 --> 00:07:45,000
+I don't see a lot of sense in reviewing all possible options for comment because most likely you want
+
+111
+00:07:45,000 --> 00:07:46,000
+to use them all.
+
+112
+00:07:47,000 --> 00:07:49,000
+I use Option L to have such formatting.
+
+113
+00:07:50,000 --> 00:07:55,000
+I will leave the link and attachments to this lesson about Allah's command and if you wish, you can
+
+114
+00:07:55,000 --> 00:07:56,000
+try different other options.
+
+115
+00:07:57,000 --> 00:07:59,000
+And we see that new file is created.
+
+116
+00:08:00,000 --> 00:08:00,000
+Here it is.
+
+117
+00:08:01,000 --> 00:08:07,000
+Let's also check that file was created in the File Explorer and we can also find it here.
+
+118
+00:08:07,000 --> 00:08:08,000
+Awesome.
+
+119
+00:08:08,000 --> 00:08:12,000
+We have just created a file and here it is in the SLC directory.
+
+120
+00:08:13,000 --> 00:08:18,000
+Before we proceed, I want to show you one more interesting command for navigation and file system.
+
+121
+00:08:18,000 --> 00:08:22,000
+We are terminal Siggie, dot, dot, dot, dot, dot.
+
+122
+00:08:22,000 --> 00:08:25,000
+Always references to the parent directory.
+
+123
+00:08:25,000 --> 00:08:31,000
+So in case you want to navigate one level up, you have to use this command and you see well, already
+
+124
+00:08:31,000 --> 00:08:35,000
+in our project directory and not in saac folder anymore.
+
+125
+00:08:36,000 --> 00:08:40,000
+Now let's pretend that our work on this task is completed and we need everything.
+
+126
+00:08:40,000 --> 00:08:42,000
+What is needed in scope of this task?
+
+127
+00:08:42,000 --> 00:08:45,000
+We have to create a command with our changes.
+
+128
+00:08:45,000 --> 00:08:50,000
+We add file to the staging area as usual, get at DOT.
+
+129
+00:08:50,000 --> 00:08:52,000
+Now we create command.
+
+130
+00:08:53,000 --> 00:08:58,000
+Gate comit dash cam, personal discount for user can be calculated.
+
+131
+00:09:01,000 --> 00:09:04,000
+Great, we have our committee now, a branch.
+
+132
+00:09:04,000 --> 00:09:11,000
+Let's check it, lock gate, lock dash to to see only last two comments.
+
+133
+00:09:11,000 --> 00:09:14,000
+We can see here that this comment is from Master Branch.
+
+134
+00:09:15,000 --> 00:09:18,000
+And here's our new comment on our new branch.
+
+135
+00:09:18,000 --> 00:09:25,000
+By the way, just to remind you that it shows you the history of the current branch only to watch all
+
+136
+00:09:25,000 --> 00:09:26,000
+committees across the repository.
+
+137
+00:09:26,000 --> 00:09:27,000
+You have to type it.
+
+138
+00:09:27,000 --> 00:09:35,000
+Look with options all like this log double dash, all towards the history of committees for the one
+
+139
+00:09:35,000 --> 00:09:43,000
+single branch type Gitlow command with the branch name like this gridlock g a double zero.
+
+140
+00:09:43,000 --> 00:09:47,000
+And do not forget, do you stop key for after completion.
+
+141
+00:09:48,000 --> 00:09:52,000
+OK, this information might help you in the future, and just for the reference.
+
+142
+00:09:53,000 --> 00:09:53,000
+Let's move on.
+
+143
+00:09:54,000 --> 00:09:58,000
+I can easily navigate between branches in my local repository.
+
+144
+00:09:58,000 --> 00:10:01,000
+We already learned the command that allows us to switch branches.
+
+145
+00:10:02,000 --> 00:10:04,000
+Now, let's switch back to the master branch.
+
+146
+00:10:05,000 --> 00:10:06,000
+You check out master.
+
+147
+00:10:07,000 --> 00:10:12,000
+I don't have to use the option because Master Branch already exists and I don't need to create a new
+
+148
+00:10:12,000 --> 00:10:12,000
+one.
+
+149
+00:10:13,000 --> 00:10:17,000
+And we can see that name of the branches changed here in the parentheses.
+
+150
+00:10:17,000 --> 00:10:20,000
+Let's check now the file lists in the SAAC folder.
+
+151
+00:10:21,000 --> 00:10:28,000
+Let's navigate to SASE folder, first CD SAAC and now let's use another command to list files.
+
+152
+00:10:29,000 --> 00:10:31,000
+Alas, that shall.
+
+153
+00:10:31,000 --> 00:10:32,000
+Wow.
+
+154
+00:10:32,000 --> 00:10:40,000
+Magic happened where discount calculation Java file, it is in another snapshot, if you don't believe
+
+155
+00:10:40,000 --> 00:10:41,000
+that file is disappeared.
+
+156
+00:10:41,000 --> 00:10:44,000
+Let me show you in the file Explorer, can you see this?
+
+157
+00:10:45,000 --> 00:10:46,000
+The file is disappeared.
+
+158
+00:10:47,000 --> 00:10:50,000
+Now you learned how to navigate between branches.
+
+159
+00:10:50,000 --> 00:10:52,000
+Can you navigate only between branches?
+
+160
+00:10:52,000 --> 00:10:53,000
+Oh, no.
+
+161
+00:10:53,000 --> 00:10:57,000
+You can also navigate to the specific limit how to do that.
+
+162
+00:10:57,000 --> 00:11:00,000
+Let me show you at the beginning.
+
+163
+00:11:00,000 --> 00:11:04,000
+Let's find the comet where I want to switch, get log dash three.
+
+164
+00:11:05,000 --> 00:11:09,000
+OK, let me switch to this cannot get out.
+
+165
+00:11:10,000 --> 00:11:14,000
+Zero six G, one B and Presenta.
+
+166
+00:11:14,000 --> 00:11:20,000
+So you need to enter a unique combination of characters so that you would understand where you are reference
+
+167
+00:11:20,000 --> 00:11:21,000
+into.
+
+168
+00:11:21,000 --> 00:11:24,000
+And now we switch to the state of this particular comet.
+
+169
+00:11:25,000 --> 00:11:31,000
+Right after you switch to the specific comet, you see one message that you are in the dust head state.
+
+170
+00:11:31,000 --> 00:11:32,000
+What does that mean?
+
+171
+00:11:33,000 --> 00:11:39,000
+That means we are not on the specific branch because most likely this comet is present in different
+
+172
+00:11:39,000 --> 00:11:39,000
+branches.
+
+173
+00:11:40,000 --> 00:11:45,000
+Even if you would create Comet being here, nobody would be able to find this comet other than we are
+
+174
+00:11:45,000 --> 00:11:51,000
+directly examining the fire because new comets won't be connected with any specific branch.
+
+175
+00:11:52,000 --> 00:11:58,000
+That means these changes can easily get lost once you check out a different revision on Branch.
+
+176
+00:11:58,000 --> 00:12:02,000
+So why then we need to check out the specific comet.
+
+177
+00:12:02,000 --> 00:12:08,000
+During your life as a software engineer, you might want to navigate to the specific committee to investigate
+
+178
+00:12:08,000 --> 00:12:11,000
+how some specific chunk of code worked in the past.
+
+179
+00:12:12,000 --> 00:12:15,000
+For example, in case to troubleshoot some defect.
+
+180
+00:12:15,000 --> 00:12:21,000
+You want to investigate how the code worked before and you want to execute this court and the market.
+
+181
+00:12:21,000 --> 00:12:24,000
+That's why you might want to navigate to the specific comet.
+
+182
+00:12:25,000 --> 00:12:32,000
+What I want you to remember is that you shouldn't do any comets in the state just investigating an experiment
+
+183
+00:12:32,000 --> 00:12:33,000
+in this fine.
+
+184
+00:12:33,000 --> 00:12:38,000
+Well, being in the state, doing the commands and the state is not the best idea.
+
+185
+00:12:39,000 --> 00:12:42,000
+Let's get back to our task branch yet.
+
+186
+00:12:42,000 --> 00:12:49,000
+Check out Geet zero zero zero one and press up two times for auto completion.
+
+187
+00:12:49,000 --> 00:12:56,000
+You have to press stop two times because we have a three zero one branch and a three zero one discount
+
+188
+00:12:56,000 --> 00:12:57,000
+calculation branch.
+
+189
+00:12:58,000 --> 00:13:02,000
+And Antep allows you to select the exact branch you need for auto completion.
+
+190
+00:13:03,000 --> 00:13:07,000
+Now, let's push it to a region, yet push our region with option.
+
+191
+00:13:07,000 --> 00:13:13,000
+You g a three zero one underscore and top key to autocomplete.
+
+192
+00:13:14,000 --> 00:13:21,000
+Nice branch was pushed to remote, new branch in remote has been created and the branch remote tracking
+
+193
+00:13:21,000 --> 00:13:22,000
+has been configured.
+
+194
+00:13:22,000 --> 00:13:24,000
+Let's check the branch in the remote repository.
+
+195
+00:13:25,000 --> 00:13:27,000
+Let's open a search directory.
+
+196
+00:13:27,000 --> 00:13:33,000
+And here you can switch branches and we can see that on our new branch, we have new file.
+
+197
+00:13:36,000 --> 00:13:44,000
+Click on Inside Sidestep Select Network here, you can see its history and see that our new branch is
+
+198
+00:13:44,000 --> 00:13:49,000
+one committee ahead of Master Branch, OK, well on how to create branches.
+
+199
+00:13:49,000 --> 00:13:53,000
+But at the beginning of the lesson, we also created one branch.
+
+200
+00:13:53,000 --> 00:13:56,000
+Let me list all branches and get back one more time.
+
+201
+00:13:57,000 --> 00:14:01,000
+Get Branch was option A this task branch.
+
+202
+00:14:01,000 --> 00:14:06,000
+I want to remove how to remove branch get branch was option.
+
+203
+00:14:06,000 --> 00:14:09,000
+The D stands for delete and the branch name.
+
+204
+00:14:10,000 --> 00:14:16,000
+We can find message that branch has been deleted, and for the sake of example, let's pretend that
+
+205
+00:14:16,000 --> 00:14:20,000
+I want to remove the calculation branch from the remote to how to do that.
+
+206
+00:14:21,000 --> 00:14:26,000
+Yet push a region was option delete and specifies a branch name here.
+
+207
+00:14:27,000 --> 00:14:28,000
+Press enter.
+
+208
+00:14:30,000 --> 00:14:32,000
+Let me open my remote repository one more time.
+
+209
+00:14:34,000 --> 00:14:39,000
+And when I try to switch branch, you see that I can't find my new branch here anymore.
+
+210
+00:14:39,000 --> 00:14:43,000
+Now you know how to remove branch locally and in remote.
+
+211
+00:14:43,000 --> 00:14:49,000
+But for our next lesson, let me push our branch to region one more time, because already in the next
+
+212
+00:14:49,000 --> 00:14:54,000
+lesson, we are going to learn how to grade pull requests and how to merge branches together.
+
+213
+00:14:55,000 --> 00:14:58,000
+Yet push a region was option you for this contemplation branch.
+
+214
+00:14:59,000 --> 00:15:05,000
+The last but nonetheless, thing that I would like to mention today is that starting from the get version
+
+215
+00:15:05,000 --> 00:15:10,000
+two point twenty three onwards, instead of checkout command, new command is also available to use
+
+216
+00:15:11,000 --> 00:15:13,000
+get switch master.
+
+217
+00:15:13,000 --> 00:15:20,000
+In case you want to switch to the new branch, you have to use C option like this and get switch options.
+
+218
+00:15:20,000 --> 00:15:23,000
+See New Branch here.
+
+219
+00:15:23,000 --> 00:15:30,000
+C option stands for create to navigate back to the previous branch type, the following gate switch
+
+220
+00:15:30,000 --> 00:15:33,000
+and hyphen and then navigated back to the Master Branch.
+
+221
+00:15:34,000 --> 00:15:35,000
+To be honest, I didn't.
+
+222
+00:15:35,000 --> 00:15:41,000
+So engineers who are already actively used to each command because it is a big habit to use Check-Out
+
+223
+00:15:41,000 --> 00:15:46,000
+Command for branch navigation in the community of engineers introducing Gates, which command wasn't
+
+224
+00:15:46,000 --> 00:15:48,000
+done to confuse developers even more.
+
+225
+00:15:49,000 --> 00:15:55,000
+The thing is that Check-Out commands sometimes might be used to reverse modifications, so to clearly
+
+226
+00:15:55,000 --> 00:16:02,000
+separate commands, Newcomen to a single goal to switch branches gets which was introduced that it.
+
+227
+00:16:03,000 --> 00:16:09,000
+I believe right now, you know about branch navigation even more than some senior engineers, and right
+
+228
+00:16:09,000 --> 00:16:13,000
+now let's recap what we have learned today in this lesson.
+
+229
+00:16:13,000 --> 00:16:17,000
+You learned what the branches you understand how mechanism of branch works.
+
+230
+00:16:18,000 --> 00:16:20,000
+Well, what is Healthpoint in it?
+
+231
+00:16:21,000 --> 00:16:22,000
+After we learn theory?
+
+232
+00:16:22,000 --> 00:16:28,000
+I showed you a few ways how to create a new branch and get ready to commit with our changes on the new
+
+233
+00:16:28,000 --> 00:16:33,000
+branch, we understood how we can navigate between the branches and what the Dutch had state is.
+
+234
+00:16:33,000 --> 00:16:40,000
+Also in this lesson we learn how to remove branches and how to use gifts which command to navigate between
+
+235
+00:16:40,000 --> 00:16:40,000
+them.
+
+236
+00:16:40,000 --> 00:16:46,000
+During the lesson you learned basically Linux commands that allows us to navigate and filesystem, create
+
+237
+00:16:46,000 --> 00:16:48,000
+files and leased files in that directory.
+
+238
+00:16:49,000 --> 00:16:53,000
+Thanks a lot for your attention and see you in the next lesson.
+

17 - GIT/010 Pull Requests & Merge Requests_en.srt

@@ -0,0 +1,632 @@
+1
+00:00:05,000 --> 00:00:11,000
+Hello there, students today will learn with you what a pull request is and how to create one after
+
+2
+00:00:11,000 --> 00:00:13,000
+we'll understand the definition of PR.
+
+3
+00:00:13,000 --> 00:00:16,000
+I will show you how you can create your first pool request.
+
+4
+00:00:16,000 --> 00:00:20,000
+We'll learn what is the difference between pool request and Richard Quest.
+
+5
+00:00:20,000 --> 00:00:23,000
+In this lesson, we are going to learn how we can match.
+
+6
+00:00:23,000 --> 00:00:28,000
+Coming from different branches will learn the difference between different methods and strategies.
+
+7
+00:00:28,000 --> 00:00:31,000
+I will show you how to add collaborator's to your repository.
+
+8
+00:00:32,000 --> 00:00:36,000
+You'll add me as a collaborator so that I will be able to evaluate your code.
+
+9
+00:00:36,000 --> 00:00:42,000
+First of all, let's understand what is a pull request pull request as a method of submitting contributions
+
+10
+00:00:42,000 --> 00:00:43,000
+to a project.
+
+11
+00:00:43,000 --> 00:00:48,000
+Imagine that you wrote a few days and implementing logic of discount calculation for your users.
+
+12
+00:00:48,000 --> 00:00:50,000
+And finally, you completed your work.
+
+13
+00:00:51,000 --> 00:00:54,000
+Now you need to match your card with the latest version of the source code.
+
+14
+00:00:55,000 --> 00:00:59,000
+Literally, you have to much of yours with comments that were done by other developers.
+
+15
+00:01:00,000 --> 00:01:02,000
+Why is this method is called a pull request.
+
+16
+00:01:02,000 --> 00:01:06,000
+You can pull changes from one branch to update another branch.
+
+17
+00:01:06,000 --> 00:01:11,000
+And by submitting a budget request, you ask other people to review your changes and pull them into
+
+18
+00:01:11,000 --> 00:01:13,000
+another branch.
+
+19
+00:01:13,000 --> 00:01:14,000
+Does it make sense now?
+
+20
+00:01:14,000 --> 00:01:17,000
+Now words to request make more sense.
+
+21
+00:01:17,000 --> 00:01:22,000
+And by the way, we'll request the terminology of the GitHub and mid-market repositories.
+
+22
+00:01:22,000 --> 00:01:26,000
+Yet Lab uses another term to describe the same process merge request.
+
+23
+00:01:27,000 --> 00:01:28,000
+The idea is pretty similar.
+
+24
+00:01:29,000 --> 00:01:32,000
+We may want to merge two branches and merge.
+
+25
+00:01:32,000 --> 00:01:37,000
+Request means that you want to ask somebody to merge the changes with the other branch.
+
+26
+00:01:37,000 --> 00:01:42,000
+Both requests and merge requests use get pull and get merge commands.
+
+27
+00:01:42,000 --> 00:01:48,000
+We are going to learn these commands in the next lessons, but don't confuse this terminology.
+
+28
+00:01:48,000 --> 00:01:55,000
+PR and Anmar refers to a much broader topic, and I believe you understand that both of these terms
+
+29
+00:01:55,000 --> 00:01:57,000
+describe the same process.
+
+30
+00:01:57,000 --> 00:02:03,000
+Now, when you understood that, let's proceed with our demo on the previous lesson remerged.
+
+31
+00:02:03,000 --> 00:02:04,000
+Our branch does a remote repository.
+
+32
+00:02:05,000 --> 00:02:08,000
+We add new file added discount calculation service.
+
+33
+00:02:08,000 --> 00:02:11,000
+Let's also change existing file for the sake of the demo.
+
+34
+00:02:12,000 --> 00:02:15,000
+Let me add spaces here in the Hello World File.
+
+35
+00:02:17,000 --> 00:02:23,000
+And I save this file now, I will add changes to the staging area and we'll make a commit the spaces
+
+36
+00:02:23,000 --> 00:02:25,000
+were added to the hello world file.
+
+37
+00:02:33,000 --> 00:02:37,000
+After I created the command, I pushed it to the remote ranch.
+
+38
+00:02:40,000 --> 00:02:45,000
+To create a pull request, you have to have two branches, and right now we have massive branch and
+
+39
+00:02:45,000 --> 00:02:47,000
+our task branch nice.
+
+40
+00:02:48,000 --> 00:02:50,000
+There are a lot of different ways to create a pull request.
+
+41
+00:02:51,000 --> 00:02:52,000
+Let me show you one of them.
+
+42
+00:02:52,000 --> 00:02:54,000
+Click on Pull Request tab here.
+
+43
+00:02:54,000 --> 00:02:57,000
+Now click on the new pull request button.
+
+44
+00:02:57,000 --> 00:03:01,000
+And here you have to specify which branch you want to pull into which branch.
+
+45
+00:03:01,000 --> 00:03:07,000
+In our case, Master is a main development branch dependent on the branch and strategy that you are
+
+46
+00:03:07,000 --> 00:03:08,000
+going to have at your work.
+
+47
+00:03:09,000 --> 00:03:14,000
+You might have development branches and development branch and Master Branch will be used only for releases.
+
+48
+00:03:15,000 --> 00:03:19,000
+In our particular case, we want to merge Task One branch into master.
+
+49
+00:03:19,000 --> 00:03:24,000
+That's why here I select a task one and here I have Master Branch.
+
+50
+00:03:24,000 --> 00:03:28,000
+Here you will see the difference between the state of these two branches.
+
+51
+00:03:28,000 --> 00:03:30,000
+Let's create a pull request.
+
+52
+00:03:30,000 --> 00:03:35,000
+Additionally, you may specify pull request description here on the right.
+
+53
+00:03:35,000 --> 00:03:38,000
+You can specify, pull, request, review and request.
+
+54
+00:03:38,000 --> 00:03:40,000
+Ehsani What is a defense review?
+
+55
+00:03:41,000 --> 00:03:43,000
+What is someone you want to review the code?
+
+56
+00:03:43,000 --> 00:03:49,000
+And this can be the person who is not necessarily responsible for merging branches, probably colleagues
+
+57
+00:03:49,000 --> 00:03:52,000
+of yours or software engineers from another development team.
+
+58
+00:03:53,000 --> 00:03:55,000
+But who needs to be aware of changes in your project?
+
+59
+00:03:56,000 --> 00:04:01,000
+On the other hand, think is someone who is responsible for emergencies, quote, this can be a tech
+
+60
+00:04:01,000 --> 00:04:07,000
+lead on your project or owner of the repository who is in charge of margin call to the master branch
+
+61
+00:04:07,000 --> 00:04:08,000
+later today.
+
+62
+00:04:08,000 --> 00:04:16,000
+I will show you how you can add me as an EHSANI right now, just click, reply, request button and
+
+63
+00:04:16,000 --> 00:04:19,000
+pull request is created on this tab.
+
+64
+00:04:19,000 --> 00:04:21,000
+You can see what commands you have on your branch.
+
+65
+00:04:22,000 --> 00:04:27,000
+On this type, you can see what files were changed in comparison with the branch where you want to major
+
+66
+00:04:27,000 --> 00:04:28,000
+changes.
+
+67
+00:04:29,000 --> 00:04:31,000
+We can see that there are two changes.
+
+68
+00:04:31,000 --> 00:04:35,000
+New file is created and the spaces are added to the hello world file.
+
+69
+00:04:36,000 --> 00:04:43,000
+Azanian reviewers will go over all your changes to investigate what exactly is changed in your pull
+
+70
+00:04:43,000 --> 00:04:43,000
+request.
+
+71
+00:04:44,000 --> 00:04:47,000
+Review process can leave commands here and the specific lines of code.
+
+72
+00:04:48,000 --> 00:04:51,000
+For example, why so many spaces here?
+
+73
+00:04:52,000 --> 00:04:58,000
+And the discussions have to be resolved, all my students who works with me offline assigned me to the
+
+74
+00:04:58,000 --> 00:05:05,000
+airport requests and during the offline lessons we reuseable request together and discuss with the group
+
+75
+00:05:05,000 --> 00:05:06,000
+what can be improved.
+
+76
+00:05:06,000 --> 00:05:10,000
+Let me also teach you how to admit to your request as an EHSANI.
+
+77
+00:05:11,000 --> 00:05:16,000
+I don't guarantee that I will be able to check each year request because for homework verification,
+
+78
+00:05:16,000 --> 00:05:21,000
+I use special type of tasks, coding exercises that verifies your homework automatically.
+
+79
+00:05:22,000 --> 00:05:24,000
+But you can learn at least how to read me here.
+
+80
+00:05:24,000 --> 00:05:30,000
+As I say, click the settings button next click manage access.
+
+81
+00:05:30,000 --> 00:05:36,000
+You might be asked to enter your password and I believe you understood that this is project specific
+
+82
+00:05:36,000 --> 00:05:37,000
+settings.
+
+83
+00:05:37,000 --> 00:05:43,000
+So in case you want to add collaborator's to your another project, you should open settings of that
+
+84
+00:05:43,000 --> 00:05:44,000
+exact repository.
+
+85
+00:05:44,000 --> 00:05:47,000
+Let's add me as a collaborator to your repository.
+
+86
+00:05:47,000 --> 00:05:50,000
+Press this green button, invite a collaborator.
+
+87
+00:05:50,000 --> 00:05:54,000
+You can find me using my nickname and repetoire.
+
+88
+00:05:54,000 --> 00:05:59,000
+I can't find myself because this is against the rules and this doesn't make sense.
+
+89
+00:05:59,000 --> 00:06:01,000
+But I can find one of my friends.
+
+90
+00:06:02,000 --> 00:06:06,000
+For example, let me find a friend of mine with the nickname Sweater Matko.
+
+91
+00:06:07,000 --> 00:06:12,000
+Similarly, you have to find my picture, click on it and press green button.
+
+92
+00:06:12,000 --> 00:06:14,000
+That is the rule of the GitHub.
+
+93
+00:06:14,000 --> 00:06:16,000
+Always press the green button.
+
+94
+00:06:16,000 --> 00:06:17,000
+Just joking.
+
+95
+00:06:18,000 --> 00:06:24,000
+I will not add Anri because I don't want to spam him because after I press green button and we should
+
+96
+00:06:24,000 --> 00:06:31,000
+receive request to become a collaborator in my repository and he also has to approve this request and
+
+97
+00:06:31,000 --> 00:06:36,000
+only after he approved the request, only after that you will be able to find him in.
+
+98
+00:06:37,000 --> 00:06:42,000
+You drop down for your pull request to navigate back to your open request.
+
+99
+00:06:42,000 --> 00:06:44,000
+You can open pull requests tab.
+
+100
+00:06:44,000 --> 00:06:46,000
+And here is our fresh PR.
+
+101
+00:06:46,000 --> 00:06:50,000
+I can procedure, I can and assign this request to myself.
+
+102
+00:06:50,000 --> 00:06:52,000
+OK, let's proceed.
+
+103
+00:06:52,000 --> 00:06:58,000
+As I mentioned, reviewers and Ehsani check your piara and once all discussions are resolved as an emergency
+
+104
+00:06:59,000 --> 00:07:03,000
+request by pressing this button, this March button has three methods.
+
+105
+00:07:03,000 --> 00:07:05,000
+They are great American.
+
+106
+00:07:05,000 --> 00:07:09,000
+Commit squash and merge rebase and merge.
+
+107
+00:07:09,000 --> 00:07:14,000
+Keeping the clean data repository is one of the top priority tasks for all contributors.
+
+108
+00:07:14,000 --> 00:07:20,000
+That clean the tree can save you a lot of time when trying to track down comments related to embark
+
+109
+00:07:20,000 --> 00:07:24,000
+or issue the default option, which is create a much.
+
+110
+00:07:24,000 --> 00:07:29,000
+It will take all comments from the PR and add them to the master brunch with a new it.
+
+111
+00:07:30,000 --> 00:07:31,000
+Let's take a look at this slide.
+
+112
+00:07:32,000 --> 00:07:35,000
+Imagine that there is a main branch we have in it.
+
+113
+00:07:35,000 --> 00:07:37,000
+Commit and commit one and two.
+
+114
+00:07:38,000 --> 00:07:43,000
+You created your feature branch and that branch we created commits three and four.
+
+115
+00:07:44,000 --> 00:07:50,000
+You prepared to request and now we select default option from merging comments and you see that you
+
+116
+00:07:50,000 --> 00:07:57,000
+can it will be created on the master branch, the commit that you will look like this merge some specific
+
+117
+00:07:57,000 --> 00:07:57,000
+branch.
+
+118
+00:07:57,000 --> 00:07:58,000
+That's it.
+
+119
+00:07:59,000 --> 00:08:04,000
+The result message is not very helpful when you will try to understand what this comment is about.
+
+120
+00:08:04,000 --> 00:08:07,000
+That's why this is not a recommended option by many developers.
+
+121
+00:08:08,000 --> 00:08:13,000
+We want to keep our gate historically and imagine the same case, but this time we would select the
+
+122
+00:08:13,000 --> 00:08:15,000
+second possible option, which is squash and match.
+
+123
+00:08:16,000 --> 00:08:22,000
+What is going to happen in this case, commence three and four will be added to the master branch.
+
+124
+00:08:22,000 --> 00:08:29,000
+What will happen is that Cummins will become blind and any other commit message can be added comit four
+
+125
+00:08:29,000 --> 00:08:36,000
+will be squashed into three and we will give any message we like with the help of GitHub interface and
+
+126
+00:08:36,000 --> 00:08:39,000
+what will happen in case I will opt for the search option.
+
+127
+00:08:39,000 --> 00:08:46,000
+Ribis and merge neurons are based in our commands are put on top of the master branch like you see on
+
+128
+00:08:46,000 --> 00:08:47,000
+this slide.
+
+129
+00:08:47,000 --> 00:08:48,000
+Come in three and four.
+
+130
+00:08:48,000 --> 00:08:51,000
+I just put on the top of the Master Branch.
+
+131
+00:08:51,000 --> 00:08:53,000
+Definitely attack.
+
+132
+00:08:53,000 --> 00:08:55,000
+It will choose strategies that you have to follow.
+
+133
+00:08:55,000 --> 00:09:00,000
+But my personal preference is rebase and match is not squash and much.
+
+134
+00:09:01,000 --> 00:09:07,000
+I believe if a developer wants to squash Kummetz, he or she has to do that locally in the local repository
+
+135
+00:09:07,000 --> 00:09:11,000
+before even pushing branch to the remote repository, but not ask us.
+
+136
+00:09:11,000 --> 00:09:16,000
+I need to squash your comments, but I also met tech leads that would prefer squash and match.
+
+137
+00:09:16,000 --> 00:09:22,000
+Rather than teach engineers how to write Canete messages and how to do squash later in this course,
+
+138
+00:09:22,000 --> 00:09:24,000
+I will show you how you can squash Kummetz.
+
+139
+00:09:25,000 --> 00:09:31,000
+Being a project owner, you can disable much methods that you don't like to do that, click on the settings
+
+140
+00:09:31,000 --> 00:09:38,000
+button and scroll page to the bottom, find merge button and uncheck methods that you don't need.
+
+141
+00:09:43,000 --> 00:09:49,000
+And if I would open my paper one more time, I can see that I have only one option available.
+
+142
+00:09:49,000 --> 00:09:52,000
+Let me select the third method and close my pull request.
+
+143
+00:09:58,000 --> 00:09:58,000
+Awesome.
+
+144
+00:09:59,000 --> 00:10:05,000
+Now, you can delete the task branch because it is not needed anymore in remote repository, since you
+
+145
+00:10:05,000 --> 00:10:11,000
+have already merged into the master branch and to not confuse anyone, let's remove it.
+
+146
+00:10:16,000 --> 00:10:20,000
+You can see that there is no task branch anymore in our remote repository.
+
+147
+00:10:21,000 --> 00:10:26,000
+Now our request is closed and we can check our current history of the master branch.
+
+148
+00:10:27,000 --> 00:10:30,000
+Make sure you are on the master branch and click here on Kummetz.
+
+149
+00:10:31,000 --> 00:10:37,000
+And we see that no other comments from Ergin were created on the committees that were created by us.
+
+150
+00:10:38,000 --> 00:10:38,000
+Great.
+
+151
+00:10:39,000 --> 00:10:44,000
+I believe now we can recap everything, what we have learned today in this lesson, we learned what
+
+152
+00:10:44,000 --> 00:10:49,000
+a pull request is and what is the difference between a pull request and a magic quest.
+
+153
+00:10:49,000 --> 00:10:52,000
+Together, we created a pull request.
+
+154
+00:10:52,000 --> 00:10:57,000
+I showed you how you can add collaborator's to the repository and we discussed what is the difference
+
+155
+00:10:57,000 --> 00:11:00,000
+between us any and reviewer and two requests.
+
+156
+00:11:00,000 --> 00:11:05,000
+Also today, we learned different management strategies and understood the difference between them.
+
+157
+00:11:06,000 --> 00:11:07,000
+That's all for now.
+
+158
+00:11:07,000 --> 00:11:10,000
+Thanks a lot for your attention and see you in the next lesson.
+

17 - GIT/011 Updating local repository (fetch, merge, pull) & Team development demo_en.srt

@@ -0,0 +1,712 @@
+1
+00:00:06,000 --> 00:00:10,000
+Hello, dear students in this class, and I'll teach you how you can update your local repository.
+
+2
+00:00:10,000 --> 00:00:16,000
+Today, I will explain to you why we need to update our local repository, how often we have to do that
+
+3
+00:00:16,000 --> 00:00:17,000
+and what commands we have to use.
+
+4
+00:00:18,000 --> 00:00:23,000
+Today, I prepared a special demo with the and flow in which I will show you commands that you are going
+
+5
+00:00:23,000 --> 00:00:25,000
+to use in most cases at your work.
+
+6
+00:00:26,000 --> 00:00:30,000
+I will tell you today, more and more to get fetch, get Merche, get pool commands.
+
+7
+00:00:30,000 --> 00:00:33,000
+Also, I will explain what does Fastforward mean.
+
+8
+00:00:34,000 --> 00:00:36,000
+We are going to learn a lot today.
+
+9
+00:00:36,000 --> 00:00:42,000
+Let's start first of all, let's answer the question why we have to update our local repository.
+
+10
+00:00:42,000 --> 00:00:47,000
+We have to update our local repository because we want to be sure that the codes that we created will
+
+11
+00:00:47,000 --> 00:00:49,000
+work with other the court as expected.
+
+12
+00:00:49,000 --> 00:00:54,000
+That is the most important reason of updating local repository as often as we can.
+
+13
+00:00:54,000 --> 00:00:56,000
+To what situations?
+
+14
+00:00:56,000 --> 00:01:01,000
+When you work on some task for one week or two weeks and when you need to merge your code with Master
+
+15
+00:01:01,000 --> 00:01:04,000
+Branch, you discover multiple conflicts in your code.
+
+16
+00:01:04,000 --> 00:01:09,000
+Today, I will show you command and real examples how you can update your local repository.
+
+17
+00:01:09,000 --> 00:01:13,000
+In previous lesson, you learned how to prepare people request and merge changes.
+
+18
+00:01:13,000 --> 00:01:19,000
+Now let's imagine that you successfully completed your previous task and you are about to start your
+
+19
+00:01:19,000 --> 00:01:20,000
+work on the new task.
+
+20
+00:01:20,000 --> 00:01:24,000
+Right now, in my local repository, I I'm on the task branch.
+
+21
+00:01:24,000 --> 00:01:29,000
+We already know that to start work on the new task and to separate code one from another, I have to
+
+22
+00:01:29,000 --> 00:01:30,000
+create a new branch.
+
+23
+00:01:31,000 --> 00:01:35,000
+Usually I want to create a new branch from the latest version of the source code.
+
+24
+00:01:35,000 --> 00:01:37,000
+So let me switch the master branch.
+
+25
+00:01:38,000 --> 00:01:43,000
+OK, I'm on the master branch, but do I have the latest version of my code here?
+
+26
+00:01:44,000 --> 00:01:49,000
+Let me navigate the SASE folder and check whether I have all the latest updates on this branch.
+
+27
+00:01:49,000 --> 00:01:53,000
+To navigate to the SRT folder, I have to type CGY SAAC.
+
+28
+00:01:54,000 --> 00:02:03,000
+OK, now let's list all the files else that shall and you see that we don't have this calculation service
+
+29
+00:02:03,000 --> 00:02:08,000
+here, why I'm on the Master Branch and we merged our changes with the master branch.
+
+30
+00:02:08,000 --> 00:02:15,000
+And the previous lesson, let's not confuse two things Master Branch and a region master branch.
+
+31
+00:02:15,000 --> 00:02:20,000
+And previous lesson when the merged request was called to the region master branch.
+
+32
+00:02:21,000 --> 00:02:24,000
+But we didn't merge, got into our master branch.
+
+33
+00:02:24,000 --> 00:02:25,000
+So what to do now?
+
+34
+00:02:26,000 --> 00:02:32,000
+Now we are going to learn a few commands, get fetch what is good for each command.
+
+35
+00:02:32,000 --> 00:02:38,000
+This command fetches all changes from the remote repository and put it in your local repository one
+
+36
+00:02:38,000 --> 00:02:39,000
+more time.
+
+37
+00:02:39,000 --> 00:02:44,000
+Important thing to mention here is that changes are not matched to your local branches.
+
+38
+00:02:44,000 --> 00:02:51,000
+So in case some comments in the region Master Branch exist, which a local repository is not aware of,
+
+39
+00:02:51,000 --> 00:02:56,000
+PFEG Command will save information about these changes in your local repository.
+
+40
+00:02:56,000 --> 00:02:58,000
+Let me press enter now.
+
+41
+00:02:58,000 --> 00:03:03,000
+Based on the log messages here, we can conclude that some changes were downloaded from the remote.
+
+42
+00:03:04,000 --> 00:03:10,000
+OK, probably now I have all the latest changes in my branch, including new file, discount calculation
+
+43
+00:03:10,000 --> 00:03:13,000
+service and all the latest changes from the Hello World File.
+
+44
+00:03:13,000 --> 00:03:16,000
+Let me check it one more time as well.
+
+45
+00:03:17,000 --> 00:03:20,000
+And again, I don't have any latest updates.
+
+46
+00:03:20,000 --> 00:03:21,000
+Why?
+
+47
+00:03:21,000 --> 00:03:27,000
+Because I have just downloaded information about these changes, but I didn't actually merge these changes
+
+48
+00:03:27,000 --> 00:03:28,000
+in the local branch.
+
+49
+00:03:29,000 --> 00:03:31,000
+Then what is the purpose of this command at all?
+
+50
+00:03:32,000 --> 00:03:37,000
+Imagine that you are working on the new changes and I don't want to merge latest code into your branch.
+
+51
+00:03:37,000 --> 00:03:39,000
+Do not break anything.
+
+52
+00:03:39,000 --> 00:03:44,000
+And you would like to know whether there are any changes in remote branch that are needed to be merged.
+
+53
+00:03:45,000 --> 00:03:47,000
+One more use case of using it for each command.
+
+54
+00:03:48,000 --> 00:03:53,000
+You can fetch changes while sitting in the office and the security VPN connection and you can merge
+
+55
+00:03:53,000 --> 00:03:58,000
+carefully your code later when you want while sitting on your cozy chair at your home.
+
+56
+00:03:59,000 --> 00:04:02,000
+But what if I am already at my home sitting on the couch?
+
+57
+00:04:03,000 --> 00:04:04,000
+What do I have to do now?
+
+58
+00:04:05,000 --> 00:04:10,000
+Now I have to merge these changes into my local branch, so I'm doing it.
+
+59
+00:04:10,000 --> 00:04:12,000
+Merge command gate.
+
+60
+00:04:12,000 --> 00:04:12,000
+Merge.
+
+61
+00:04:13,000 --> 00:04:14,000
+Awesome.
+
+62
+00:04:14,000 --> 00:04:20,000
+It looks like some changes have been merged with my master branch, I see Fastforward message here.
+
+63
+00:04:21,000 --> 00:04:22,000
+What does that mean?
+
+64
+00:04:23,000 --> 00:04:29,000
+And fast forward is what it does when you merge or a base against a branch that is simply ahead, the
+
+65
+00:04:29,000 --> 00:04:30,000
+one you have checked out.
+
+66
+00:04:31,000 --> 00:04:38,000
+That means there was no branches and that is the new value of the branch is a direct descendant of the
+
+67
+00:04:38,000 --> 00:04:39,000
+prior values.
+
+68
+00:04:39,000 --> 00:04:46,000
+So we had a region master branch that contains commands that are descendant of our previous master branch.
+
+69
+00:04:46,000 --> 00:04:52,000
+That's why we call such merging as fast forward now when we have merged the latest updates.
+
+70
+00:04:52,000 --> 00:04:56,000
+Let me check list of files and dash I'll command.
+
+71
+00:04:57,000 --> 00:04:57,000
+Wow.
+
+72
+00:04:57,000 --> 00:05:01,000
+Finally, I have this calculation service file in my file system.
+
+73
+00:05:01,000 --> 00:05:05,000
+That is the latest changes that have emerged in the remote repository.
+
+74
+00:05:05,000 --> 00:05:07,000
+Let me also check that update from Hello.
+
+75
+00:05:07,000 --> 00:05:09,000
+World File is also in place.
+
+76
+00:05:09,000 --> 00:05:14,000
+And previously we updated Hillenburg file and put extra lines in it.
+
+77
+00:05:14,000 --> 00:05:17,000
+Let me open this file in a text editor.
+
+78
+00:05:17,000 --> 00:05:18,000
+Nana.
+
+79
+00:05:18,000 --> 00:05:20,000
+Hello, World Dodgeville.
+
+80
+00:05:20,000 --> 00:05:21,000
+Nice.
+
+81
+00:05:21,000 --> 00:05:24,000
+I see only one characters outplays place here.
+
+82
+00:05:24,000 --> 00:05:30,000
+Let me exit now Ed by pressing control and simultaneously as described here.
+
+83
+00:05:31,000 --> 00:05:38,000
+Now, I want you to learn one more command that is good, but what is it command essentially getable
+
+84
+00:05:38,000 --> 00:05:41,000
+is a combination of two actions, PFEG and March.
+
+85
+00:05:42,000 --> 00:05:47,000
+So in case you want to fetch all changes from the remote repository and at the same time merge them
+
+86
+00:05:47,000 --> 00:05:50,000
+into the branch you have to use to command.
+
+87
+00:05:50,000 --> 00:05:52,000
+You're our demo today.
+
+88
+00:05:52,000 --> 00:05:56,000
+I want to show you real life scenarios that will happen with you on your workplace.
+
+89
+00:05:56,000 --> 00:06:02,000
+I want you not to learn just commands, but understand how you will use it while working with steam.
+
+90
+00:06:02,000 --> 00:06:08,000
+The name of this I prepared enter and flow that will show you the full scenario of what we learned so
+
+91
+00:06:08,000 --> 00:06:08,000
+far.
+
+92
+00:06:09,000 --> 00:06:11,000
+And I want you to be ready.
+
+93
+00:06:11,000 --> 00:06:16,000
+I want you to understand how team development is happening together.
+
+94
+00:06:16,000 --> 00:06:18,000
+We're going to imitate the next generation.
+
+95
+00:06:19,000 --> 00:06:23,000
+Imagine that we work on the implementation of virtual card in our online shop.
+
+96
+00:06:24,000 --> 00:06:25,000
+We are working on this task.
+
+97
+00:06:26,000 --> 00:06:32,000
+At the same time, developer number two works on the implementation of service that will provide functionality
+
+98
+00:06:32,000 --> 00:06:33,000
+of stock management.
+
+99
+00:06:34,000 --> 00:06:38,000
+Both engineers created the branch from the same revision, from the same command.
+
+100
+00:06:39,000 --> 00:06:43,000
+After that we created bool request and our changes were successfully merged.
+
+101
+00:06:43,000 --> 00:06:49,000
+And after that, developer number two created Pulu request and his request was successfully matched.
+
+102
+00:06:49,000 --> 00:06:56,000
+After that, we want to proceed with implementation of the next task product preservation, let's say.
+
+103
+00:06:56,000 --> 00:07:02,000
+But before start work on the new task, we have to pull all the latest changes to create the branch
+
+104
+00:07:02,000 --> 00:07:03,000
+with the latest updates.
+
+105
+00:07:03,000 --> 00:07:06,000
+And we have to execute get command.
+
+106
+00:07:07,000 --> 00:07:11,000
+Hope you you're not confused, but I want you to be prepared for the real life.
+
+107
+00:07:11,000 --> 00:07:14,000
+And this is the easiest real life scenario with only two developers.
+
+108
+00:07:15,000 --> 00:07:18,000
+Let them together, try to reproduce this in error.
+
+109
+00:07:18,000 --> 00:07:21,000
+So we are going to have next steps.
+
+110
+00:07:21,000 --> 00:07:28,000
+Developer one and two created branches and the changes after that, both engineers created peers that
+
+111
+00:07:28,000 --> 00:07:31,000
+were a match to the original master branch developer.
+
+112
+00:07:31,000 --> 00:07:34,000
+One post latest changes to start work on the new task.
+
+113
+00:07:35,000 --> 00:07:35,000
+Let's start.
+
+114
+00:07:36,000 --> 00:07:38,000
+Here is what we are going to do on our book.
+
+115
+00:07:39,000 --> 00:07:41,000
+Let's check the status of the master branch.
+
+116
+00:07:42,000 --> 00:07:45,000
+So it is up to date with the region masterbrand.
+
+117
+00:07:45,000 --> 00:07:46,000
+Cool.
+
+118
+00:07:46,000 --> 00:07:55,000
+Now let me create a new branch gates, which was option C G, a three zero to virtual car with which
+
+119
+00:07:55,000 --> 00:07:56,000
+to the new branch.
+
+120
+00:07:57,000 --> 00:07:59,000
+Let's imitate implementation of this task.
+
+121
+00:07:59,000 --> 00:08:04,000
+I will create a special directory called Card and Mkdir Card.
+
+122
+00:08:06,000 --> 00:08:08,000
+Here is a command that creates a directory.
+
+123
+00:08:09,000 --> 00:08:13,000
+Now let's navigate into this directory, S.A.G. cars.
+
+124
+00:08:14,000 --> 00:08:19,000
+Now let's create card management service file and we will pretend that there is a task implemented in
+
+125
+00:08:19,000 --> 00:08:20,000
+this file.
+
+126
+00:08:21,000 --> 00:08:23,000
+Darch Card Management Service Dajarra.
+
+127
+00:08:24,000 --> 00:08:31,000
+By the way, you can't push and commit only folder's if you want to set some basic folder structure
+
+128
+00:08:31,000 --> 00:08:32,000
+for your program.
+
+129
+00:08:32,000 --> 00:08:34,000
+There should be files in these folders.
+
+130
+00:08:35,000 --> 00:08:40,000
+OK, now let's add this to Sustagen yet at DOT and commit this change.
+
+131
+00:08:41,000 --> 00:08:45,000
+Yet commit dash and card management is implemented.
+
+132
+00:08:50,000 --> 00:08:58,000
+OK, we have a comment now let's push it to our region, yet push the our region keets three zero to
+
+133
+00:08:58,000 --> 00:08:59,000
+your troll car.
+
+134
+00:09:03,000 --> 00:09:05,000
+We'll create a pull request now.
+
+135
+00:09:05,000 --> 00:09:10,000
+Give me a few seconds here, you already know how to create a PR from the previous lesson.
+
+136
+00:09:17,000 --> 00:09:20,000
+PR is created what we want merge, they scored so far.
+
+137
+00:09:21,000 --> 00:09:26,000
+Meanwhile, developer number two created a separate branch to implement stock management.
+
+138
+00:09:30,000 --> 00:09:37,000
+OK, the same as here developer number two and the master branch and in the SLC directory, he wants
+
+139
+00:09:37,000 --> 00:09:44,000
+to start work on the new task and create a new branch Gates, which is option C, a three zero three
+
+140
+00:09:44,000 --> 00:09:45,000
+stock management.
+
+141
+00:09:45,000 --> 00:09:50,000
+Let's create a new folder in the SAAC directory mkdir stock.
+
+142
+00:09:51,000 --> 00:09:54,000
+Right now I create a directory in the search folder.
+
+143
+00:09:54,000 --> 00:09:57,000
+Let me navigate their C.G. stock.
+
+144
+00:09:58,000 --> 00:10:00,000
+OK, I'm here now.
+
+145
+00:10:00,000 --> 00:10:08,000
+Let me create a file Derg Stock Management Service Dot Java cuz that and this file to the staging area
+
+146
+00:10:09,000 --> 00:10:16,000
+get at dot and now let's commit yet command dash and stock management is implemented.
+
+147
+00:10:18,000 --> 00:10:25,000
+And let's push it to the remote, get push there for you, originally, a three zero three stock management.
+
+148
+00:10:27,000 --> 00:10:30,000
+Now I have to create a request for this change.
+
+149
+00:10:39,000 --> 00:10:41,000
+Let us manage to pull requests now.
+
+150
+00:10:58,000 --> 00:11:05,000
+And you see that quote in Monster is updated in caves during the new task, implementation you would
+
+151
+00:11:05,000 --> 00:11:08,000
+need is a correct management service or stock management service.
+
+152
+00:11:08,000 --> 00:11:14,000
+It is better for you to learn it earlier, because, first of all, probably you're going to use this
+
+153
+00:11:14,000 --> 00:11:18,000
+court or this court might break your court anyway.
+
+154
+00:11:19,000 --> 00:11:25,000
+It is better to have all changes from all developers on place in your local repository before start
+
+155
+00:11:25,000 --> 00:11:26,000
+any new work.
+
+156
+00:11:26,000 --> 00:11:31,000
+And finally, we return to the main branch and want to start work on the new task.
+
+157
+00:11:32,000 --> 00:11:37,000
+But right now, we have to make sure that we have the latest changes in the master branch before create
+
+158
+00:11:37,000 --> 00:11:38,000
+a new branch.
+
+159
+00:11:39,000 --> 00:11:45,000
+OK, what we have to do now, probably you would say get pfeg and get merge, but let's execute git
+
+160
+00:11:45,000 --> 00:11:46,000
+pull command.
+
+161
+00:11:48,000 --> 00:11:55,000
+Awesome, we pulled our changes and we are ready to work on the new task you see here, I pulled card
+
+162
+00:11:55,000 --> 00:12:00,000
+management service and stock management service and you see that we don't necessarily have to do get
+
+163
+00:12:00,000 --> 00:12:01,000
+pfeg.
+
+164
+00:12:01,000 --> 00:12:02,000
+And after that it gets merged.
+
+165
+00:12:02,000 --> 00:12:06,000
+Command get combines these two commands into one.
+
+166
+00:12:06,000 --> 00:12:11,000
+I can check my card and stock directory and find files there, you see.
+
+167
+00:12:12,000 --> 00:12:18,000
+We finished our practice exercise, Holmes's A Small Demo will help you to understand how we can use
+
+168
+00:12:18,000 --> 00:12:18,000
+it.
+
+169
+00:12:18,000 --> 00:12:21,000
+You're the game collaboration and new task implementation.
+
+170
+00:12:22,000 --> 00:12:24,000
+Let's recap what we have learned today.
+
+171
+00:12:25,000 --> 00:12:28,000
+Today, we learned why we need to update our local repository.
+
+172
+00:12:28,000 --> 00:12:32,000
+We also learned to get Fairgate marriage and get boogerman.
+
+173
+00:12:32,000 --> 00:12:38,000
+Now you know that you have to update your master branch before you start working on each new task.
+
+174
+00:12:38,000 --> 00:12:44,000
+You also understand the difference between a get FEG marriage and pull commence today.
+
+175
+00:12:44,000 --> 00:12:50,000
+So what is fastforward in it and at the end of the lesson I showed you and flow of how team development
+
+176
+00:12:50,000 --> 00:12:52,000
+is look like with the help of the get.
+
+177
+00:12:53,000 --> 00:12:54,000
+Thanks a lot for your attention.
+
+178
+00:12:55,000 --> 00:12:57,000
+See you in the next lesson.
+

17 - GIT/012 Merge Conflicts_en.srt

@@ -0,0 +1,796 @@
+1
+00:00:06,000 --> 00:00:11,000
+Hello, yes, students, in this lesson, you learn what most conflicts are in simple words, I will
+
+2
+00:00:11,000 --> 00:00:17,000
+explain in one, much conflicts could appear together, will reproduce real life scenarios, merge conflict.
+
+3
+00:00:17,000 --> 00:00:23,000
+And what is even more interesting, I will tell you how to solve major conflicts together during the
+
+4
+00:00:23,000 --> 00:00:23,000
+drama.
+
+5
+00:00:23,000 --> 00:00:28,000
+We are going to solve much conflict that will appear during the pulling from the remote repository.
+
+6
+00:00:28,000 --> 00:00:32,000
+And as usual, let's together give a definition to the conflict.
+
+7
+00:00:33,000 --> 00:00:39,000
+The conflict is a specific event that takes place when it is unable to resolve differences in code between
+
+8
+00:00:39,000 --> 00:00:40,000
+two commits automatically.
+
+9
+00:00:41,000 --> 00:00:45,000
+This is a event which we can't avoid during the development in the team.
+
+10
+00:00:45,000 --> 00:00:49,000
+Usually it may happen when two developers change in the same line of code.
+
+11
+00:00:49,000 --> 00:00:50,000
+How it can be.
+
+12
+00:00:50,000 --> 00:00:54,000
+For example, imagine that in our project we have some web page and developer.
+
+13
+00:00:54,000 --> 00:00:59,000
+No one worked on the task to implement login button and added some styles.
+
+14
+00:00:59,000 --> 00:01:06,000
+She included these styles into our HTML page and developing a number to work on the task for implementing
+
+15
+00:01:06,000 --> 00:01:08,000
+carcel on the home page.
+
+16
+00:01:08,000 --> 00:01:15,000
+Engineer number two also had to do adjustments in the home page because he wanted to include his custom
+
+17
+00:01:15,000 --> 00:01:18,000
+styles and adjust page markup a bit.
+
+18
+00:01:18,000 --> 00:01:21,000
+First, Engineer pushed his code to his original branch.
+
+19
+00:01:22,000 --> 00:01:25,000
+He also created a pool request that was successfully merged.
+
+20
+00:01:25,000 --> 00:01:28,000
+But one second engineer tried to create a pool request.
+
+21
+00:01:28,000 --> 00:01:31,000
+He received an error that there are no conflicts.
+
+22
+00:01:31,000 --> 00:01:32,000
+Why?
+
+23
+00:01:32,000 --> 00:01:38,000
+Because two engineers and they did the same file home that each demo and most likely in the same lines
+
+24
+00:01:38,000 --> 00:01:39,000
+of code.
+
+25
+00:01:39,000 --> 00:01:47,000
+And you can't understand what version of code is the latest one and the proper one, yet can't match
+
+26
+00:01:47,000 --> 00:01:48,000
+this code automatically.
+
+27
+00:01:48,000 --> 00:01:51,000
+This situation is called much conflict.
+
+28
+00:01:52,000 --> 00:01:53,000
+What to do in this case?
+
+29
+00:01:53,000 --> 00:01:56,000
+In this case, conflict should be resolved manually.
+
+30
+00:01:56,000 --> 00:02:02,000
+Engineer number two has to pull all the latest changes into his branch, investigate where exactly this
+
+31
+00:02:02,000 --> 00:02:06,000
+conflict is appeared and resolve it by saying resolve it.
+
+32
+00:02:06,000 --> 00:02:11,000
+I mean change source code and create a command that will be approved to the gate that these changes
+
+33
+00:02:11,000 --> 00:02:16,000
+are created intentionally and well reviewed by some engineer after much conflict.
+
+34
+00:02:16,000 --> 00:02:19,000
+As a result, the file can be merged to the master branch.
+
+35
+00:02:19,000 --> 00:02:25,000
+So today we are going to review the example, how this much conflict is created and how to solve it.
+
+36
+00:02:25,000 --> 00:02:31,000
+Let's start to start with I'd like to inform you that for the sake of the demo before this lesson,
+
+37
+00:02:31,000 --> 00:02:36,000
+I created this home, the HTML file in the Web content directory.
+
+38
+00:02:36,000 --> 00:02:37,000
+Let's take a look at it.
+
+39
+00:02:39,000 --> 00:02:46,000
+As you can see, this is the simplest possible HTML file with an overall text in it, nothing special
+
+40
+00:02:46,000 --> 00:02:48,000
+to not lose focus from the goal of our lesson.
+
+41
+00:02:49,000 --> 00:02:53,000
+This file was created in the separate branch and merged with the remote repository.
+
+42
+00:02:53,000 --> 00:02:55,000
+You already know how to do that.
+
+43
+00:02:55,000 --> 00:02:57,000
+Now imagine the developer.
+
+44
+00:02:57,000 --> 00:03:02,000
+One wanted to create styles for login button and pop up on the homepage.
+
+45
+00:03:02,000 --> 00:03:04,000
+Let's create a new branch for that.
+
+46
+00:03:04,000 --> 00:03:10,000
+Yes, which was option C Geet three zero four login styling.
+
+47
+00:03:11,000 --> 00:03:16,000
+Just for the sake of example, let's imagine that we have some styles folder where Altius has files
+
+48
+00:03:16,000 --> 00:03:19,000
+should be stored for those who are not aware.
+
+49
+00:03:19,000 --> 00:03:25,000
+Files with the Texas extension are used for styling your elements on the HTML pages.
+
+50
+00:03:25,000 --> 00:03:28,000
+This stands for Cascadian Stylesheets.
+
+51
+00:03:28,000 --> 00:03:32,000
+OK, let me create Styles folder in my SAAC directory.
+
+52
+00:03:33,000 --> 00:03:34,000
+Mkdir Styles.
+
+53
+00:03:35,000 --> 00:03:40,000
+Now let's imagine that during the task implementation developer, no one created Neuters as file was
+
+54
+00:03:40,000 --> 00:03:46,000
+description of custom styles touch styles again nauseousness.
+
+55
+00:03:46,000 --> 00:03:55,000
+Also Injinoo number one adjusted Holmwood HTML file to include this style there to reproduce the steps
+
+56
+00:03:55,000 --> 00:03:56,000
+that I did in this lesson.
+
+57
+00:03:56,000 --> 00:03:59,000
+You can use any text or code editor you would like.
+
+58
+00:03:59,000 --> 00:04:05,000
+For the sake of the demo, I will use Nano text editor to save time on switching between different screens.
+
+59
+00:04:05,000 --> 00:04:14,000
+Let me open home e-mail file to adjusted nano web content slash hamdard HDMI.
+
+60
+00:04:15,000 --> 00:04:20,000
+Just to remind you, I always use that key for auto completion internal according to rules.
+
+61
+00:04:20,000 --> 00:04:27,000
+I can include TSF style on this page like this and the hat that I should put my link back with.
+
+62
+00:04:27,000 --> 00:04:38,000
+The path to the text file had a link rel stylesheet HSF double dot slash styles slash again not to assess
+
+63
+00:04:39,000 --> 00:04:42,000
+and clotheslined attack and had attack is closed.
+
+64
+00:04:43,000 --> 00:04:45,000
+This is not a tumultuous assess.
+
+65
+00:04:45,000 --> 00:04:48,000
+That's why I won't stop on the things I wrote.
+
+66
+00:04:48,000 --> 00:04:52,000
+But I would like to draw attention to the lines which we changed.
+
+67
+00:04:53,000 --> 00:04:55,000
+We changed line three, four and five.
+
+68
+00:04:56,000 --> 00:04:57,000
+Remember this.
+
+69
+00:04:57,000 --> 00:05:00,000
+This is important for understanding of the conflict topic.
+
+70
+00:05:00,000 --> 00:05:03,000
+I access this file and save it now.
+
+71
+00:05:03,000 --> 00:05:08,000
+Add everything to the staging area, create and commit and push it to the original branch.
+
+72
+00:05:09,000 --> 00:05:12,000
+Those are the things that we have already learned in the previous lessons.
+
+73
+00:05:12,000 --> 00:05:14,000
+Give me a few seconds here.
+
+74
+00:05:15,000 --> 00:05:25,000
+Get at not yet committed again and again yet Bush with option you originally a three zero for Logan
+
+75
+00:05:25,000 --> 00:05:26,000
+stylin.
+
+76
+00:05:27,000 --> 00:05:33,000
+Also, I can create pool requests, but the important thing right now is not to match your pool request.
+
+77
+00:05:33,000 --> 00:05:36,000
+Why we need to imitate case one.
+
+78
+00:05:36,000 --> 00:05:42,000
+Developer number two started implementation of his task without knowing about changes in the home.
+
+79
+00:05:42,000 --> 00:05:44,000
+Each team will understand.
+
+80
+00:05:44,000 --> 00:05:47,000
+Right now, let's pretend that we as the other engineer.
+
+81
+00:05:48,000 --> 00:05:54,000
+Let me let me get back to the massive branch and create new branch for my task from it gets which M.
+
+82
+00:05:55,000 --> 00:05:59,000
+Gates, which was option C, a three zero five homecourt.
+
+83
+00:05:59,000 --> 00:06:01,000
+So nice.
+
+84
+00:06:02,000 --> 00:06:04,000
+Now I have to create my own styles for Carasso.
+
+85
+00:06:05,000 --> 00:06:09,000
+Let me create file in styles directory take into account with each branch.
+
+86
+00:06:09,000 --> 00:06:11,000
+I don't have styles directory.
+
+87
+00:06:11,000 --> 00:06:13,000
+Here, let me show you this.
+
+88
+00:06:14,000 --> 00:06:19,000
+It is optional and you can see that Styles directory is not created yet on this branch.
+
+89
+00:06:20,000 --> 00:06:23,000
+Let me quickly created mkdir styles.
+
+90
+00:06:23,000 --> 00:06:32,000
+Now I can create miticides, file touch styles Carasso not to assess and now let me adjust home html
+
+91
+00:06:32,000 --> 00:06:33,000
+file.
+
+92
+00:06:34,000 --> 00:06:40,000
+None of content slash home dot HMO, I will put reference to my sister's file here.
+
+93
+00:06:41,000 --> 00:06:48,000
+At least, Carol Stylesheet, a triple double dose slash style slash carrousel, not Ceressus, and
+
+94
+00:06:48,000 --> 00:06:49,000
+close the attack.
+
+95
+00:06:50,000 --> 00:06:52,000
+Attack is also closed.
+
+96
+00:06:53,000 --> 00:07:00,000
+And you can notice that I changed lines number three, four and five, the same lines that as a developer
+
+97
+00:07:00,000 --> 00:07:01,000
+changed.
+
+98
+00:07:01,000 --> 00:07:02,000
+This is important.
+
+99
+00:07:03,000 --> 00:07:05,000
+Let me close and save this file.
+
+100
+00:07:06,000 --> 00:07:09,000
+I'm going to add all changes to the staging area.
+
+101
+00:07:09,000 --> 00:07:11,000
+Come in then and push to the remote repository.
+
+102
+00:07:12,000 --> 00:07:13,000
+Give me a few seconds here.
+
+103
+00:07:14,000 --> 00:07:15,000
+Get at DOT.
+
+104
+00:07:15,000 --> 00:07:18,000
+You'd commit option and carrousel on the home page.
+
+105
+00:07:19,000 --> 00:07:23,000
+Get push resorption you a region key, a three zero five home Carasso.
+
+106
+00:07:24,000 --> 00:07:30,000
+Now imagine that during implementation of the home Carasso task pool request for logging's talent was
+
+107
+00:07:30,000 --> 00:07:31,000
+matched by a technique.
+
+108
+00:07:32,000 --> 00:07:33,000
+Let me merge it.
+
+109
+00:07:35,000 --> 00:07:38,000
+OK, it is merged and nothing bad happened.
+
+110
+00:07:39,000 --> 00:07:42,000
+Now let me create a pool request for carrousel implementation.
+
+111
+00:07:46,000 --> 00:07:53,000
+First of all, I see here warning that this branch can't be automatically merged, but still I can create
+
+112
+00:07:53,000 --> 00:07:53,000
+a pull request.
+
+113
+00:07:54,000 --> 00:08:00,000
+And after I created a request, I see that my emerge button is disabled because of the conflicts you
+
+114
+00:08:00,000 --> 00:08:06,000
+can see in here that you can solve conflicts in the Web editor, while this can be an option in case
+
+115
+00:08:06,000 --> 00:08:08,000
+of the resolving of the small conflict.
+
+116
+00:08:08,000 --> 00:08:10,000
+This is not an option for the most cases.
+
+117
+00:08:11,000 --> 00:08:11,000
+Why?
+
+118
+00:08:12,000 --> 00:08:13,000
+Because of the few reasons.
+
+119
+00:08:14,000 --> 00:08:20,000
+Reason number one, most likely you have more complicated conflicts than we have now here.
+
+120
+00:08:20,000 --> 00:08:26,000
+And this is not convenient to change it in Web editor reason number two, after resolving conflicts,
+
+121
+00:08:26,000 --> 00:08:30,000
+you want to be sure that you didn't break anything for this?
+
+122
+00:08:30,000 --> 00:08:37,000
+You have to have your code on your local machine to run unit tests or integration tests on case HDMI
+
+123
+00:08:37,000 --> 00:08:42,000
+additon to open each HTML page to make sure that everything is OK with your markup.
+
+124
+00:08:42,000 --> 00:08:46,000
+So I will show you how you can solve conflicts on your local machine.
+
+125
+00:08:46,000 --> 00:08:48,000
+Let me get back to the Kit Bash.
+
+126
+00:08:48,000 --> 00:08:55,000
+I'm on my task home carrousel branch, as you can see here, to resolve the conflicts, I have to merge
+
+127
+00:08:55,000 --> 00:08:57,000
+a region master branch into the current branch.
+
+128
+00:08:57,000 --> 00:08:59,000
+You already know that.
+
+129
+00:08:59,000 --> 00:09:01,000
+Merge command, merge different branches.
+
+130
+00:09:01,000 --> 00:09:07,000
+But let me show you how you can merge remote branch into the current one yet pull a region master.
+
+131
+00:09:08,000 --> 00:09:13,000
+You also learned in previous lessons that pull command, merge changes into the branch.
+
+132
+00:09:14,000 --> 00:09:18,000
+And here you can see the message that there is a conflict in this file.
+
+133
+00:09:18,000 --> 00:09:20,000
+Automatic merge is failed.
+
+134
+00:09:20,000 --> 00:09:22,000
+Let resolve conflicts.
+
+135
+00:09:22,000 --> 00:09:26,000
+I have to open in any code ed file where I have conflicts.
+
+136
+00:09:27,000 --> 00:09:28,000
+For the sake of the demo.
+
+137
+00:09:28,000 --> 00:09:31,000
+I will use Nnenna Ed in this lesson now.
+
+138
+00:09:31,000 --> 00:09:35,000
+No map content egholm not HMO.
+
+139
+00:09:35,000 --> 00:09:39,000
+And here you can find different symbols that get added to our file.
+
+140
+00:09:40,000 --> 00:09:42,000
+That is how it shows the conflicts.
+
+141
+00:09:42,000 --> 00:09:48,000
+You already know that hat is a pointer to the place where you are currently in your working directory.
+
+142
+00:09:48,000 --> 00:09:50,000
+So here you can see our version of code.
+
+143
+00:09:51,000 --> 00:09:57,000
+We want to insert carrousel to assess and here changes from the master branch that were merged after
+
+144
+00:09:57,000 --> 00:09:59,000
+implementation of task by the world number one.
+
+145
+00:10:00,000 --> 00:10:01,000
+And check some of that comment.
+
+146
+00:10:02,000 --> 00:10:06,000
+We have to adjust file after some analysis.
+
+147
+00:10:06,000 --> 00:10:10,000
+I understood that in this particular case, I want to keep my changes and changes of developer.
+
+148
+00:10:10,000 --> 00:10:13,000
+No one will see that line.
+
+149
+00:10:13,000 --> 00:10:18,000
+Three and five were the same in two versions of code, but only in line number four was different.
+
+150
+00:10:19,000 --> 00:10:21,000
+We used different sets, file names here.
+
+151
+00:10:22,000 --> 00:10:24,000
+Let me add just markup accordingly.
+
+152
+00:10:25,000 --> 00:10:28,000
+After I'm done with changes, I exit and save this file.
+
+153
+00:10:29,000 --> 00:10:35,000
+Here in parentheses, you see mansions that I'm in the process of merging two branches also.
+
+154
+00:10:35,000 --> 00:10:39,000
+You can see that suggested to me to create the once conflicts are resolved.
+
+155
+00:10:40,000 --> 00:10:42,000
+Let's follow this advice and create a committee.
+
+156
+00:10:43,000 --> 00:10:49,000
+If you would check status with get status comment, then we would see that new file logging success
+
+157
+00:10:49,000 --> 00:10:51,000
+is already added to the staging area.
+
+158
+00:10:52,000 --> 00:10:55,000
+That's the one from the master branch where we don't have any conflicts.
+
+159
+00:10:56,000 --> 00:10:59,000
+And here is the file where we had a conflict.
+
+160
+00:10:59,000 --> 00:11:07,000
+Let me add it to the staging area yet at not now let's check status and we can see that all files are
+
+161
+00:11:07,000 --> 00:11:08,000
+in the staging area.
+
+162
+00:11:08,000 --> 00:11:12,000
+Now, let's create a climate gate comment.
+
+163
+00:11:12,000 --> 00:11:18,000
+I will skip the message now because for such cases get already stolen message for me, the message that
+
+164
+00:11:18,000 --> 00:11:21,000
+states that must branch is merged into the task branch.
+
+165
+00:11:22,000 --> 00:11:27,000
+Let's close this text editor and we can see that we successfully merged changes.
+
+166
+00:11:27,000 --> 00:11:31,000
+Now we need to update our branch in remote repository.
+
+167
+00:11:31,000 --> 00:11:32,000
+Let's push our changes.
+
+168
+00:11:33,000 --> 00:11:34,000
+Get Bush.
+
+169
+00:11:36,000 --> 00:11:39,000
+Now, let me refresh page with my pool request.
+
+170
+00:11:42,000 --> 00:11:50,000
+I can't rebase and merge, and I will explain why in the next lesson, but I can merge with creating
+
+171
+00:11:50,000 --> 00:11:51,000
+a new command.
+
+172
+00:11:52,000 --> 00:11:57,000
+And if you remember that in previous lesson I showed you different margined strategies and how to allow
+
+173
+00:11:57,000 --> 00:12:02,000
+different merging strategies here in the settings and the merge button section.
+
+174
+00:12:02,000 --> 00:12:06,000
+Congratulations yourself, your first merge conflict.
+
+175
+00:12:06,000 --> 00:12:08,000
+But unfortunately, we are not falling right now.
+
+176
+00:12:08,000 --> 00:12:11,000
+Best practices of keeping it historically.
+
+177
+00:12:12,000 --> 00:12:12,000
+Why?
+
+178
+00:12:13,000 --> 00:12:17,000
+Because first of all, we created separate committees during the merger and Origin Master Branch was
+
+179
+00:12:17,000 --> 00:12:23,000
+our task branch and right now we are under the risk to create one more committee for merging branches.
+
+180
+00:12:24,000 --> 00:12:28,000
+Can you imagine how our history tree will look like after all of this?
+
+181
+00:12:29,000 --> 00:12:31,000
+Your tax rate will be disappointed.
+
+182
+00:12:31,000 --> 00:12:33,000
+Just joking in the next lessons.
+
+183
+00:12:33,000 --> 00:12:37,000
+I will show you how to avoid this and how to keep your tax rate happy.
+
+184
+00:12:38,000 --> 00:12:42,000
+But still to understand the next lessons, you had to understand this lesson.
+
+185
+00:12:42,000 --> 00:12:47,000
+And why pull an origin master into your branch to resolve conflicts is not the best approach.
+
+186
+00:12:48,000 --> 00:12:53,000
+While this approach is still valid in some companies and in some development teams, that is not the
+
+187
+00:12:53,000 --> 00:12:57,000
+approach which I would approve in my development team and in my company.
+
+188
+00:12:57,000 --> 00:13:02,000
+Probably already aware that I am CEO of my own software development company.
+
+189
+00:13:02,000 --> 00:13:08,000
+And when I interviewed engineers, I paid extra attention to the experience of working with it, because
+
+190
+00:13:08,000 --> 00:13:14,000
+during the development of complex projects and cross-functional teams, these skills are very important.
+
+191
+00:13:14,000 --> 00:13:19,000
+I am going to create top notch software engineers from you during this course.
+
+192
+00:13:19,000 --> 00:13:22,000
+That's why I will run as a way to solve financial conflicts.
+
+193
+00:13:22,000 --> 00:13:27,000
+OK, and if we are good for the day, let's recap what we have learned today.
+
+194
+00:13:28,000 --> 00:13:34,000
+In this lesson, you learned what marriage conflicts are more over together, even we produce much conflict
+
+195
+00:13:34,000 --> 00:13:35,000
+in real life.
+
+196
+00:13:35,000 --> 00:13:41,000
+Example, you learned how to resolve marriage conflicts locally and how to manage a region must rush
+
+197
+00:13:41,000 --> 00:13:43,000
+into a task branch.
+
+198
+00:13:43,000 --> 00:13:45,000
+Thanks a lot for your attention.
+
+199
+00:13:45,000 --> 00:13:47,000
+See you in the next lesson.
+

17 - GIT/013 Git Rebasing & Force Update of remote repository_en.srt

@@ -0,0 +1,968 @@
+1
+00:00:06,000 --> 00:00:11,000
+Hello, dear students, in this lesson, we'll learn what a great rebellion is and what for some day
+
+2
+00:00:11,000 --> 00:00:11,000
+it is.
+
+3
+00:00:12,000 --> 00:00:14,000
+I will show you how and when you can apply.
+
+4
+00:00:14,000 --> 00:00:15,000
+Get your base command.
+
+5
+00:00:15,000 --> 00:00:18,000
+I will explain what rebase actually means.
+
+6
+00:00:18,000 --> 00:00:23,000
+Also, I will explain the difference between good marriage and get to base after.
+
+7
+00:00:23,000 --> 00:00:24,000
+We will understand Ceri.
+
+8
+00:00:24,000 --> 00:00:30,000
+We'll take a look at real example and we'll learn how we can use our base command on a daily basis.
+
+9
+00:00:31,000 --> 00:00:35,000
+You're going to see how to keep your military clean during the lesson.
+
+10
+00:00:35,000 --> 00:00:39,000
+You're going to learn how to solve conflicts that could appear during the invasion.
+
+11
+00:00:39,000 --> 00:00:45,000
+On the other branch, on real examples, I will show you what gets replaced with option continue means
+
+12
+00:00:46,000 --> 00:00:47,000
+and how to complete the remaining process.
+
+13
+00:00:48,000 --> 00:00:53,000
+After we change the local comment history, I will show you what force of date is and how force with
+
+14
+00:00:53,000 --> 00:00:55,000
+lease option may help us.
+
+15
+00:00:55,000 --> 00:01:01,000
+And at the end of the lesson I'm going to share with you four Rules of Happy Perquisite by Peter.
+
+16
+00:01:02,000 --> 00:01:03,000
+Just jokin is always.
+
+17
+00:01:04,000 --> 00:01:09,000
+And to start with, let's discuss the problem which we faced during the previous lesson, if we resolved
+
+18
+00:01:09,000 --> 00:01:16,000
+conflicts with Bookham and you saw that one more comment was created and you also saw that I can't merge
+
+19
+00:01:16,000 --> 00:01:20,000
+with the best strategy to M. I can only merge with new command.
+
+20
+00:01:20,000 --> 00:01:27,000
+So our problem is how to get his territory clean, the presidential and union commands.
+
+21
+00:01:27,000 --> 00:01:30,000
+Let's understand first what our base is and how it works.
+
+22
+00:01:30,000 --> 00:01:35,000
+In general, there are two main ways to integrate changes from one branch into another.
+
+23
+00:01:35,000 --> 00:01:38,000
+Zaya Yes, merge and military base.
+
+24
+00:01:38,000 --> 00:01:42,000
+We already learned in previous lessons more about Gaete merging branches.
+
+25
+00:01:43,000 --> 00:01:47,000
+Now let's understand on the high level what is a rebase let's recall an example.
+
+26
+00:01:47,000 --> 00:01:52,000
+When we had the branches, the easiest way to synchronize the branches is to merge them.
+
+27
+00:01:53,000 --> 00:01:58,000
+So to merge C3 and C4 snapshots, we have to create one more snapshot.
+
+28
+00:01:58,000 --> 00:01:59,000
+Thus one more comment.
+
+29
+00:01:59,000 --> 00:02:00,000
+C five.
+
+30
+00:02:01,000 --> 00:02:04,000
+This option works just fine and we saw how it works.
+
+31
+00:02:05,000 --> 00:02:10,000
+But do we have another option that will not create additional senseless commit?
+
+32
+00:02:11,000 --> 00:02:12,000
+Yes, we do.
+
+33
+00:02:12,000 --> 00:02:15,000
+Based on the awesome branch, what does that mean?
+
+34
+00:02:15,000 --> 00:02:20,000
+We can take changes that we have in C four commit and put them on top of C three.
+
+35
+00:02:21,000 --> 00:02:27,000
+That mean you can take changes that were done on one branch and apply those changes on the other branch.
+
+36
+00:02:28,000 --> 00:02:33,000
+In our example, I can execute Command Guitry Bassmaster while being on the experiment branch.
+
+37
+00:02:34,000 --> 00:02:38,000
+This will lead us to the good history that you can see on this slide.
+
+38
+00:02:38,000 --> 00:02:42,000
+You can see that C snapshot is going right after C three.
+
+39
+00:02:43,000 --> 00:02:48,000
+This will allow the great pull request and merge branches and help with the and strategy.
+
+40
+00:02:48,000 --> 00:02:54,000
+In this particular scenario, we can switch back to the Master Branch and do fastforward much like it
+
+41
+00:02:54,000 --> 00:02:55,000
+has shown on the slide.
+
+42
+00:02:56,000 --> 00:03:02,000
+And in this case, you can see that there are no any other comments from Najin branches and we have
+
+43
+00:03:02,000 --> 00:03:03,000
+Coingate history.
+
+44
+00:03:04,000 --> 00:03:09,000
+We're also going to have lessons about interactive freebase a bit later in this course, where I will
+
+45
+00:03:09,000 --> 00:03:14,000
+show you how you can use reverse command to combine commands or to change commit messages.
+
+46
+00:03:15,000 --> 00:03:20,000
+But in this lesson, we'll run the rebels command only from the point of margin changes from different
+
+47
+00:03:20,000 --> 00:03:20,000
+branches.
+
+48
+00:03:21,000 --> 00:03:26,000
+On the previous slide, you saw base command to replace changes from another branch.
+
+49
+00:03:26,000 --> 00:03:31,000
+But in real life example, later today we are going to use a bit another variation of this command,
+
+50
+00:03:31,000 --> 00:03:33,000
+get ball with a base option.
+
+51
+00:03:34,000 --> 00:03:38,000
+So what is the difference between a military base and pool with a base option?
+
+52
+00:03:38,000 --> 00:03:43,000
+Using base command replaces the branch which we want get bored with.
+
+53
+00:03:43,000 --> 00:03:48,000
+The base option can be treated as shorthand for git fetch and then get through base command.
+
+54
+00:03:48,000 --> 00:03:54,000
+You will be able to fetch all the latest changes from the remote repository prior to revising our code
+
+55
+00:03:54,000 --> 00:03:54,000
+on top of it.
+
+56
+00:03:55,000 --> 00:04:01,000
+Because if I would just use Guitry Bassmaster Command, it would only take into account what local repository
+
+57
+00:04:01,000 --> 00:04:05,000
+is already aware of, but not the changes from the remote repository.
+
+58
+00:04:05,000 --> 00:04:07,000
+This is very important, practical tip.
+
+59
+00:04:08,000 --> 00:04:13,000
+That's why this video, of course, is so valuable to all my students, because even if you would read
+
+60
+00:04:13,000 --> 00:04:17,000
+documentation and use it to base, you wouldn't read the expected goal.
+
+61
+00:04:17,000 --> 00:04:20,000
+And it is not clear that Boogerman has a base option.
+
+62
+00:04:20,000 --> 00:04:23,000
+If only you read all your documentation.
+
+63
+00:04:23,000 --> 00:04:30,000
+Probably by this very moment of our lesson, you are wondering what is better get much or get base?
+
+64
+00:04:31,000 --> 00:04:34,000
+Which one should I use to give you the full answer?
+
+65
+00:04:34,000 --> 00:04:39,000
+I'd like you to understand one more time what repositories history means from different point of use.
+
+66
+00:04:40,000 --> 00:04:43,000
+Repository history is the records of what actually happened.
+
+67
+00:04:44,000 --> 00:04:51,000
+From this point of view, it might seem like not a good idea to change history from this angle.
+
+68
+00:04:51,000 --> 00:04:56,000
+Using the base is similar to lying about what actually happened in your repository.
+
+69
+00:04:56,000 --> 00:05:01,000
+But is this valid comment all the times or there are some exceptions?
+
+70
+00:05:01,000 --> 00:05:07,000
+What if there are a series of large companies that brings us almost zero information about conversion
+
+71
+00:05:07,000 --> 00:05:08,000
+improvements?
+
+72
+00:05:08,000 --> 00:05:12,000
+That brings us information that branches remerged OK?
+
+73
+00:05:12,000 --> 00:05:17,000
+And what that is logical is that branches should be merged at some point.
+
+74
+00:05:17,000 --> 00:05:24,000
+But I am more interested in the functionality of the specific version of code rather than the fact that
+
+75
+00:05:24,000 --> 00:05:25,000
+there was not much.
+
+76
+00:05:25,000 --> 00:05:29,000
+That is the point of view on what repositories history means.
+
+77
+00:05:30,000 --> 00:05:35,000
+My personal opinion is that we should treat our history as a story of how our project was made.
+
+78
+00:05:35,000 --> 00:05:40,000
+If we are writing a story, there is no harm in doing side notes and tracking each step.
+
+79
+00:05:41,000 --> 00:05:46,000
+But when times come to release the story and show it to the world, I want to tell more coherent story
+
+80
+00:05:46,000 --> 00:05:48,000
+without all my drafts.
+
+81
+00:05:48,000 --> 00:05:49,000
+And that didn't pass.
+
+82
+00:05:50,000 --> 00:05:55,000
+But despite my personal opinion, I believe you understood that there is no right answer which approach
+
+83
+00:05:55,000 --> 00:05:56,000
+is better.
+
+84
+00:05:56,000 --> 00:06:02,000
+And just keep in mind that all projects are different and there is no silver bullet for each project.
+
+85
+00:06:02,000 --> 00:06:04,000
+There is no one size fits all approach.
+
+86
+00:06:05,000 --> 00:06:09,000
+But being a true professional, you have to be aware about different points of view.
+
+87
+00:06:09,000 --> 00:06:13,000
+That's why I believe it is important for me to share this with you.
+
+88
+00:06:14,000 --> 00:06:20,000
+OK, now, when you understood the theory of revision, I suggest looking at our practical example.
+
+89
+00:06:21,000 --> 00:06:26,000
+Keen to understand the damage in this lesson, you have to understand the drama from previous lesson
+
+90
+00:06:26,000 --> 00:06:32,000
+because we have the same context as in previous lesson will proceed from the point where we finished
+
+91
+00:06:32,000 --> 00:06:32,000
+previous time.
+
+92
+00:06:33,000 --> 00:06:37,000
+Let me call Gitlow command of last's recommits gridlock.
+
+93
+00:06:37,000 --> 00:06:39,000
+Dash three here.
+
+94
+00:06:39,000 --> 00:06:43,000
+You can see that I have not commit one result together.
+
+95
+00:06:43,000 --> 00:06:44,000
+Much conflict.
+
+96
+00:06:44,000 --> 00:06:50,000
+You can see here that this much coming of this Ansar's Kummetz, you can check, check, checksum here.
+
+97
+00:06:51,000 --> 00:06:53,000
+And here's a reference to Logan pop up.
+
+98
+00:06:53,000 --> 00:06:54,000
+You're in Logan Command.
+
+99
+00:06:55,000 --> 00:06:59,000
+That is command that emerged from a three zero four branch.
+
+100
+00:06:59,000 --> 00:07:06,000
+And we see in parentheses that it is from a region master branch and we have our own command, which
+
+101
+00:07:06,000 --> 00:07:12,000
+we did, and scope of this branch gursel on the home page and then Miyu another option of handling much
+
+102
+00:07:12,000 --> 00:07:13,000
+conflict.
+
+103
+00:07:13,000 --> 00:07:19,000
+And to them or a base to you, I suggest we said in our state to the state of this comit carrousel on
+
+104
+00:07:19,000 --> 00:07:24,000
+the home page before we even did a good pull origin master command.
+
+105
+00:07:25,000 --> 00:07:30,000
+Right now you are going to get reset command, which we are going to learn in the separate lesson.
+
+106
+00:07:30,000 --> 00:07:36,000
+I have to use it in this lesson so that you would keep track of all my changes in the git repository.
+
+107
+00:07:36,000 --> 00:07:42,000
+I believe that showing all my actions and to you is the best way to learn such a powerful tool as good.
+
+108
+00:07:43,000 --> 00:07:50,000
+I will perform the next command and I will explain in short what it does get reset.
+
+109
+00:07:50,000 --> 00:07:56,000
+This command can reset state of your file system to the specific revision option.
+
+110
+00:07:56,000 --> 00:08:02,000
+Hard reset command has different modes will learn all possible modes in the separate lesson.
+
+111
+00:08:03,000 --> 00:08:09,000
+Heart means that files from the other region will be restored and all changes from other revisions will
+
+112
+00:08:09,000 --> 00:08:10,000
+be removed.
+
+113
+00:08:11,000 --> 00:08:13,000
+Had had is appointed as a current place.
+
+114
+00:08:13,000 --> 00:08:17,000
+And yet that is our last comment to the one.
+
+115
+00:08:17,000 --> 00:08:22,000
+This means reset state of our file system to the state that was one commit ago.
+
+116
+00:08:22,000 --> 00:08:26,000
+That is right before we pulled changes from the original Master Branch.
+
+117
+00:08:26,000 --> 00:08:30,000
+Let's press enter and here we are on the castle on the home page.
+
+118
+00:08:30,000 --> 00:08:32,000
+Commit, let's check.
+
+119
+00:08:32,000 --> 00:08:33,000
+Commit history now.
+
+120
+00:08:33,000 --> 00:08:35,000
+Get locked command.
+
+121
+00:08:36,000 --> 00:08:36,000
+Awesome.
+
+122
+00:08:37,000 --> 00:08:39,000
+We can even check our file system.
+
+123
+00:08:39,000 --> 00:08:45,000
+Let me show you that we don't have Logan says says file from another branch, said Stiles.
+
+124
+00:08:47,000 --> 00:08:54,000
+And residential, and you can see that we only have Gursel to file and we don't have any logins, he
+
+125
+00:08:54,000 --> 00:08:55,000
+says file here.
+
+126
+00:08:56,000 --> 00:08:56,000
+Cool.
+
+127
+00:08:56,000 --> 00:09:00,000
+Let's get back to the SASE directory, Siggie double dot.
+
+128
+00:09:01,000 --> 00:09:04,000
+And now, instead of doing it, pull origin master.
+
+129
+00:09:04,000 --> 00:09:07,000
+Let me execute another commands that we have learned today.
+
+130
+00:09:08,000 --> 00:09:11,000
+Get was optional base a region master.
+
+131
+00:09:12,000 --> 00:09:18,000
+This was expected in case we wouldn't have any major conflicts, rebates would be very smooth, but
+
+132
+00:09:18,000 --> 00:09:20,000
+that is way too easy for you.
+
+133
+00:09:20,000 --> 00:09:23,000
+Let me show you how to resolve NAHJ conflicts during the invasion.
+
+134
+00:09:24,000 --> 00:09:30,000
+I believe you remember that we expect much conflict in home, not HTML file, but this time we have
+
+135
+00:09:30,000 --> 00:09:32,000
+a bit different message.
+
+136
+00:09:32,000 --> 00:09:38,000
+We see that error happened during the invasion and commit could not be applied here.
+
+137
+00:09:38,000 --> 00:09:41,000
+It leaves a hint for you what to do in this case.
+
+138
+00:09:41,000 --> 00:09:44,000
+We have to resolve all conflicts manually.
+
+139
+00:09:44,000 --> 00:09:50,000
+After that, we have to either add or remove files to the staging area and execute rebels continued
+
+140
+00:09:50,000 --> 00:09:51,000
+command.
+
+141
+00:09:52,000 --> 00:09:58,000
+I don't recommend this keep this coming like it is shown here, because our goal is to resolve conflicts
+
+142
+00:09:58,000 --> 00:09:59,000
+and finish freebasing.
+
+143
+00:10:00,000 --> 00:10:05,000
+In case you understand that it is a mistake and something is going wrong, you can execute Guitry base
+
+144
+00:10:05,000 --> 00:10:07,000
+with abort option.
+
+145
+00:10:07,000 --> 00:10:13,000
+By the way, here in parentheses, you can see indications that we are in the process of revision right
+
+146
+00:10:13,000 --> 00:10:15,000
+now, but let us resolve conflicts.
+
+147
+00:10:16,000 --> 00:10:19,000
+Nano web content slash home, not HDMI.
+
+148
+00:10:20,000 --> 00:10:22,000
+Let me quickly resolve these conflicts.
+
+149
+00:10:23,000 --> 00:10:27,000
+After conflicts are resolved, I close and save this file.
+
+150
+00:10:28,000 --> 00:10:36,000
+Now, as it was said before, I have to add files to the staging area yet at DOD and now we can proceed
+
+151
+00:10:36,000 --> 00:10:41,000
+our amazing database, continue to get offers me to adjust my message.
+
+152
+00:10:41,000 --> 00:10:45,000
+But I want to keep it the same cursor on the homepage.
+
+153
+00:10:45,000 --> 00:10:47,000
+That sounds just perfect.
+
+154
+00:10:48,000 --> 00:10:54,000
+So I just closed the file and I see a message that I was successfully based on the other branch.
+
+155
+00:10:55,000 --> 00:10:59,000
+Now let me update my branch in remote repository to update my poll request.
+
+156
+00:11:00,000 --> 00:11:01,000
+Get Bush.
+
+157
+00:11:02,000 --> 00:11:04,000
+Oh, I see error here.
+
+158
+00:11:05,000 --> 00:11:06,000
+Those were rejected.
+
+159
+00:11:07,000 --> 00:11:07,000
+Why?
+
+160
+00:11:07,000 --> 00:11:14,000
+Because I already had a ranch in the remote repository, my region, a three zero five home carousel
+
+161
+00:11:14,000 --> 00:11:17,000
+branch, has different comment history rather than my local branch.
+
+162
+00:11:17,000 --> 00:11:24,000
+Now, because the base command changes get history and it is not smart enough to understand this.
+
+163
+00:11:25,000 --> 00:11:27,000
+Forget it is just looks like a mess.
+
+164
+00:11:27,000 --> 00:11:31,000
+Now, our local branch and their branch has a different history of comments.
+
+165
+00:11:31,000 --> 00:11:35,000
+Let's take a look one more time at the history of Cummins of the remote branch.
+
+166
+00:11:36,000 --> 00:11:37,000
+Can you see these two comments?
+
+167
+00:11:38,000 --> 00:11:40,000
+And you can see comments, checksum.
+
+168
+00:11:40,000 --> 00:11:45,000
+Now let's return to get Bush and check Commissaire git log.
+
+169
+00:11:45,000 --> 00:11:47,000
+Deshotel, can I see this?
+
+170
+00:11:48,000 --> 00:11:52,000
+We put our cursor on the homepage comit right on top of the massive branch.
+
+171
+00:11:53,000 --> 00:11:58,000
+That is actually what we base does and pay attention to check some here.
+
+172
+00:11:58,000 --> 00:11:59,000
+Can I see that?
+
+173
+00:11:59,000 --> 00:12:02,000
+It was the same message has different checks.
+
+174
+00:12:03,000 --> 00:12:07,000
+OK, well understood that our committee history is different on different branches.
+
+175
+00:12:07,000 --> 00:12:08,000
+But what to do now?
+
+176
+00:12:08,000 --> 00:12:11,000
+I need to tell you which version is correct.
+
+177
+00:12:12,000 --> 00:12:18,000
+I know that my current branch is the most relevant branch, so I have to update my original branch so
+
+178
+00:12:18,000 --> 00:12:21,000
+that it would have the same comment history as my local branch.
+
+179
+00:12:21,000 --> 00:12:26,000
+To do this, I need to perform the next command, get Bush with option F.
+
+180
+00:12:27,000 --> 00:12:29,000
+F stands for Force Update.
+
+181
+00:12:30,000 --> 00:12:37,000
+Be extra careful when you do this, because force update will erase changes that are currently present
+
+182
+00:12:37,000 --> 00:12:41,000
+in the remote repository in this branch if you are going to use from base command.
+
+183
+00:12:41,000 --> 00:12:45,000
+That means sometimes you would need to use force update option.
+
+184
+00:12:45,000 --> 00:12:47,000
+But one more time.
+
+185
+00:12:48,000 --> 00:12:49,000
+Be extra careful.
+
+186
+00:12:50,000 --> 00:12:57,000
+Use this option only with your branches, only with branches that only you are aware of, because in
+
+187
+00:12:57,000 --> 00:13:03,000
+case somebody created the branch from your branch and you change history and your branch was merged,
+
+188
+00:13:03,000 --> 00:13:08,000
+that will cause extra efforts for the engineer who created the branch from your branch.
+
+189
+00:13:08,000 --> 00:13:15,000
+Real life example, KYAY automation engineer who is going to help you with writing your tests for your
+
+190
+00:13:15,000 --> 00:13:16,000
+home.
+
+191
+00:13:16,000 --> 00:13:23,000
+Carasso created his own branch from your branch, your updated comment history and merge it to the master
+
+192
+00:13:23,000 --> 00:13:25,000
+key engineer can't match.
+
+193
+00:13:25,000 --> 00:13:32,000
+Mostly his branch needs that your branch needs to master right now without freebasing and solving conflicts
+
+194
+00:13:32,000 --> 00:13:33,000
+one more time.
+
+195
+00:13:33,000 --> 00:13:39,000
+Or imagine that key engineer merged his or her changes into your branch.
+
+196
+00:13:39,000 --> 00:13:46,000
+And by applying for update, he overrides those changes and the documents were lost.
+
+197
+00:13:46,000 --> 00:13:51,000
+This even sounds complicated, so please try to avoid this.
+
+198
+00:13:52,000 --> 00:13:58,000
+Today, we're going to create a few rules that will save you a ton of time and your nerves in the future.
+
+199
+00:13:58,000 --> 00:14:01,000
+I call this rules for rules of happy workwise.
+
+200
+00:14:01,000 --> 00:14:03,000
+Get by and repeat the rule.
+
+201
+00:14:03,000 --> 00:14:09,000
+Number one, always create branches from the master branch, but not from the other development branches.
+
+202
+00:14:10,000 --> 00:14:18,000
+Rule number two, force update only your own branches that you can be sure nobody using because of the
+
+203
+00:14:18,000 --> 00:14:21,000
+risk of losing data force is very risky mode.
+
+204
+00:14:22,000 --> 00:14:27,000
+What is less risky is the rule of thumb is using force with less option.
+
+205
+00:14:27,000 --> 00:14:35,000
+What is this about force, which is a safer option that will not override any work on the remote branch
+
+206
+00:14:35,000 --> 00:14:39,000
+if more comments were added to the remote branch by another team member.
+
+207
+00:14:39,000 --> 00:14:42,000
+Based on this, let's make rule number three.
+
+208
+00:14:42,000 --> 00:14:47,000
+When you need to use force update, always use force with less option.
+
+209
+00:14:47,000 --> 00:14:52,000
+I can't even count how much time this simple rule saves me tons of time.
+
+210
+00:14:53,000 --> 00:14:56,000
+So we use force with this option.
+
+211
+00:14:56,000 --> 00:14:57,000
+Let's press enter button.
+
+212
+00:14:58,000 --> 00:15:04,000
+Take into account no update in my branch, I successfully updated my branch in the remote repository
+
+213
+00:15:04,000 --> 00:15:07,000
+and my request let's check my power now.
+
+214
+00:15:08,000 --> 00:15:09,000
+Can you see this?
+
+215
+00:15:09,000 --> 00:15:15,000
+I have one comment instead of two and also check some of the comment, carrousel on the home page is
+
+216
+00:15:15,000 --> 00:15:16,000
+changed.
+
+217
+00:15:17,000 --> 00:15:19,000
+Now I can use Rebase and my strategy.
+
+218
+00:15:20,000 --> 00:15:21,000
+That is awesome.
+
+219
+00:15:21,000 --> 00:15:25,000
+We did this together and now it is time for the rule number four.
+
+220
+00:15:26,000 --> 00:15:29,000
+Rule number four always are based on a region.
+
+221
+00:15:29,000 --> 00:15:31,000
+Must have brunch before creating a comet.
+
+222
+00:15:32,000 --> 00:15:34,000
+Now you know how to replace and M..
+
+223
+00:15:35,000 --> 00:15:41,000
+I would even say that this is a best practice to rule based on the region master as often as you can
+
+224
+00:15:41,000 --> 00:15:47,000
+to fix conflicts gradually and to test your implementation on the latest version of the code during
+
+225
+00:15:47,000 --> 00:15:50,000
+the development to not spend a lot of time.
+
+226
+00:15:50,000 --> 00:15:56,000
+When you worked one week on your task and after solving all conflicts, you realized that feature doesn't
+
+227
+00:15:56,000 --> 00:15:57,000
+work as expected.
+
+228
+00:15:57,000 --> 00:16:00,000
+OK, which is really a lot today.
+
+229
+00:16:00,000 --> 00:16:02,000
+Let's recap what we have learned today.
+
+230
+00:16:03,000 --> 00:16:04,000
+In this lesson.
+
+231
+00:16:04,000 --> 00:16:09,000
+We learned what the basis we understood the difference between merge and rebase.
+
+232
+00:16:09,000 --> 00:16:15,000
+We tried to answer the question, what is better to use it, merge or get rebates from different points
+
+233
+00:16:15,000 --> 00:16:15,000
+of view?
+
+234
+00:16:16,000 --> 00:16:19,000
+One real example, you saw how a command works.
+
+235
+00:16:19,000 --> 00:16:22,000
+You know, when you need to execute, get from base, continued command.
+
+236
+00:16:23,000 --> 00:16:27,000
+Also Villon, when we need to use force update mode.
+
+237
+00:16:27,000 --> 00:16:31,000
+And how fast was this option can help us to not override other comments.
+
+238
+00:16:32,000 --> 00:16:36,000
+And at the end of the lesson we reviewed for roles, have happy work with it.
+
+239
+00:16:36,000 --> 00:16:38,000
+We learned a lot today.
+
+240
+00:16:38,000 --> 00:16:40,000
+I'm really happy you saw this lesson.
+
+241
+00:16:41,000 --> 00:16:42,000
+Thanks a lot for your attention.
+
+242
+00:16:42,000 --> 00:16:46,000
+The students have agreed the rest of the day and see you in the next lesson.
+

17 - GIT/014 Git Interactive Rebase_en.srt

@@ -0,0 +1,540 @@
+1
+00:00:06,000 --> 00:00:06,000
+Hello, Jim.
+
+2
+00:00:06,000 --> 00:00:10,000
+In this lesson, I'm going to show you how interactive remise works.
+
+3
+00:00:10,000 --> 00:00:15,000
+Today, I will show you when and how you can use interactive free based on real examples.
+
+4
+00:00:15,000 --> 00:00:20,000
+I will show you how you can change any message from your repository history and we'll show you how to
+
+5
+00:00:20,000 --> 00:00:22,000
+combine to commit into one.
+
+6
+00:00:22,000 --> 00:00:25,000
+After this lesson, you learn how to squash it.
+
+7
+00:00:26,000 --> 00:00:30,000
+I will share with you best practices of working with give and keep good history clean.
+
+8
+00:00:31,000 --> 00:00:35,000
+Let's start and we will start from the example that we had in previous lesson.
+
+9
+00:00:35,000 --> 00:00:40,000
+Imagine that the men on the task branch, you understood that you have to do one more comment.
+
+10
+00:00:41,000 --> 00:00:43,000
+Probably you forgot to add some styles.
+
+11
+00:00:43,000 --> 00:00:50,000
+For the sake of example, let me adjust carousel to assess file nonhostile slash carousel dot to assess.
+
+12
+00:00:51,000 --> 00:00:55,000
+I will just put new ones here to not spend a lot of time on modifying this file.
+
+13
+00:00:56,000 --> 00:01:03,000
+I add these changes to the staging area get at DOT and now you need to include latest changes into your
+
+14
+00:01:03,000 --> 00:01:03,000
+branch.
+
+15
+00:01:03,000 --> 00:01:04,000
+What you can do.
+
+16
+00:01:05,000 --> 00:01:09,000
+The first option, which we have already learned, and which I want to remind you is to amend the last
+
+17
+00:01:09,000 --> 00:01:11,000
+commit like this yet come.
+
+18
+00:01:11,000 --> 00:01:15,000
+It was optional and was optional added.
+
+19
+00:01:15,000 --> 00:01:19,000
+This will allow you to change your latest commit without changing commit message.
+
+20
+00:01:19,000 --> 00:01:25,000
+But let's pretend you didn't want to amend commit for some reasons and want to create one more comment.
+
+21
+00:01:26,000 --> 00:01:30,000
+When you're dealing with comments that were merged into your branch by a colleague of yours who doesn't
+
+22
+00:01:30,000 --> 00:01:32,000
+know, get as good as you are.
+
+23
+00:01:32,000 --> 00:01:35,000
+And that's why you have Xhaka credit for this change.
+
+24
+00:01:36,000 --> 00:01:37,000
+Let me create a committee now.
+
+25
+00:01:38,000 --> 00:01:41,000
+You can meet with Option M to assess class for homecare.
+
+26
+00:01:41,000 --> 00:01:46,000
+So Slider is added, OK, and now you have to comments on your branch.
+
+27
+00:01:46,000 --> 00:01:48,000
+Let's add one more comment.
+
+28
+00:01:48,000 --> 00:01:51,000
+We need this to have at least three comments to play with on our branch.
+
+29
+00:01:52,000 --> 00:01:55,000
+That is for the sake of the demo, the same as before.
+
+30
+00:01:55,000 --> 00:02:03,000
+I will quickly adjust our two file and I will create one more snapshot nonhostile slash Carasso dot
+
+31
+00:02:03,000 --> 00:02:05,000
+to assess engine your lines here.
+
+32
+00:02:07,000 --> 00:02:13,000
+You'd commit dash a dash and one Monticello's glass for home Kurzel Slider is added.
+
+33
+00:02:16,000 --> 00:02:18,000
+OK, now we have three comments.
+
+34
+00:02:19,000 --> 00:02:23,000
+Imagine that you are not happy with Canet message and want to change it.
+
+35
+00:02:23,000 --> 00:02:25,000
+What options do you have to adjust?
+
+36
+00:02:25,000 --> 00:02:32,000
+Can it get can it was option amand but what if you don't want to change economic message for the latest
+
+37
+00:02:32,000 --> 00:02:32,000
+comment?
+
+38
+00:02:33,000 --> 00:02:37,000
+What if you want to change economic message that goes right before the last one?
+
+39
+00:02:37,000 --> 00:02:39,000
+Interactive information will help you with this.
+
+40
+00:02:40,000 --> 00:02:42,000
+What is interactive freebase?
+
+41
+00:02:42,000 --> 00:02:44,000
+Interactive Freebasing?
+
+42
+00:02:44,000 --> 00:02:49,000
+It makes it easy to clean up your comments before they get based or moved onto another branch.
+
+43
+00:02:50,000 --> 00:02:59,000
+Military base was option I had to the three I stands for interactive free base, we want to proceed
+
+44
+00:02:59,000 --> 00:03:02,000
+with interactive rebates for last's recommits.
+
+45
+00:03:02,000 --> 00:03:04,000
+That's why I wrote Hand.
+
+46
+00:03:04,000 --> 00:03:06,000
+That is a pointer to our current state.
+
+47
+00:03:06,000 --> 00:03:07,000
+Delusory.
+
+48
+00:03:08,000 --> 00:03:10,000
+That means recommits back from the current one.
+
+49
+00:03:11,000 --> 00:03:12,000
+Lets press enter now.
+
+50
+00:03:13,000 --> 00:03:13,000
+Awesome.
+
+51
+00:03:14,000 --> 00:03:19,000
+Here we see our three last Kummetz starting from the latest to the newest.
+
+52
+00:03:19,000 --> 00:03:25,000
+And I see that the change message I have to write are letter near the camp where I want to change cammed
+
+53
+00:03:25,000 --> 00:03:31,000
+message and I want to change not the last message but commit message that goes before the last one.
+
+54
+00:03:32,000 --> 00:03:38,000
+So I put our letter next to the USS Glassful home carrousel is added commit message.
+
+55
+00:03:39,000 --> 00:03:46,000
+I say file by pressing control and s and close the text editor in this window we can change comit message
+
+56
+00:03:46,000 --> 00:03:47,000
+as we wish.
+
+57
+00:03:47,000 --> 00:03:54,000
+Let's add more details to first class for scrolling Carasso on the home page is added.
+
+58
+00:03:55,000 --> 00:04:01,000
+Now, let's save this file and close the text editor here, you can see notification that we successfully
+
+59
+00:04:01,000 --> 00:04:02,000
+based and updated the branch.
+
+60
+00:04:03,000 --> 00:04:06,000
+Let's check in with history, long story.
+
+61
+00:04:07,000 --> 00:04:14,000
+And we can see that my message for this CANET and check some of this can it was changed grade after
+
+62
+00:04:14,000 --> 00:04:15,000
+we changed the message for comment.
+
+63
+00:04:15,000 --> 00:04:21,000
+We took a look at our branch history one more time and realize that it is way too many comments about
+
+64
+00:04:21,000 --> 00:04:22,000
+the same thing.
+
+65
+00:04:22,000 --> 00:04:26,000
+We have three comments right now for the one single piece of functionality.
+
+66
+00:04:27,000 --> 00:04:32,000
+We know that in case we would put this change to the remote repository, our tech might be disappointed.
+
+67
+00:04:32,000 --> 00:04:33,000
+Why?
+
+68
+00:04:33,000 --> 00:04:37,000
+Because was the one single task grade style and focus on the home page.
+
+69
+00:04:38,000 --> 00:04:40,000
+We have three committees right now.
+
+70
+00:04:40,000 --> 00:04:46,000
+Instead of having one single command, your tablet might ask you to squash comments in order to keep
+
+71
+00:04:46,000 --> 00:04:47,000
+Guitry clean.
+
+72
+00:04:47,000 --> 00:04:48,000
+What does squash mean?
+
+73
+00:04:49,000 --> 00:04:55,000
+In other words, you can combine two or more commands into the one to ensure clean good history.
+
+74
+00:04:55,000 --> 00:05:02,000
+You can mount Kummetz so they would disappear, but not the changes which were done in scope of these
+
+75
+00:05:02,000 --> 00:05:03,000
+snapshots.
+
+76
+00:05:04,000 --> 00:05:09,000
+Let's imagine the case that during the development of your task, you get multiple commands and after
+
+77
+00:05:09,000 --> 00:05:14,000
+that you realized that it would be better to have either one commit a group, commit in a different
+
+78
+00:05:14,000 --> 00:05:16,000
+manner how to do this.
+
+79
+00:05:17,000 --> 00:05:20,000
+Interactive rebase will help us also with this task.
+
+80
+00:05:20,000 --> 00:05:22,000
+Guitry base was option.
+
+81
+00:05:22,000 --> 00:05:24,000
+I had killed the three.
+
+82
+00:05:25,000 --> 00:05:26,000
+You're already familiar with this command.
+
+83
+00:05:27,000 --> 00:05:31,000
+You can specify as many comments backwards as you want instead of three.
+
+84
+00:05:31,000 --> 00:05:36,000
+I am specifying only three right now because we all remember four rules of happy work with Gaete.
+
+85
+00:05:36,000 --> 00:05:42,000
+From the previous lesson, I can modify only commands that are on my branch but not commit that already
+
+86
+00:05:42,000 --> 00:05:48,000
+exist and must have branch I press and at the same time in history, as we already saw today, was ablated
+
+87
+00:05:48,000 --> 00:05:49,000
+commit message.
+
+88
+00:05:50,000 --> 00:05:54,000
+We can see that to combine commands we can use either squash or fix up.
+
+89
+00:05:54,000 --> 00:05:56,000
+Will you squash one.
+
+90
+00:05:56,000 --> 00:05:58,000
+We want to change it message and fix up one.
+
+91
+00:05:58,000 --> 00:05:59,000
+We want to keep coming.
+
+92
+00:05:59,000 --> 00:06:01,000
+The message of the first command.
+
+93
+00:06:02,000 --> 00:06:07,000
+Most likely if you combine multiple commands, you want to reflect this in the correct message.
+
+94
+00:06:07,000 --> 00:06:11,000
+That's why more often you're going to squash rather than fix.
+
+95
+00:06:11,000 --> 00:06:15,000
+An important thing to mention here, you can squash the first commit in the list.
+
+96
+00:06:16,000 --> 00:06:23,000
+In other words, here in the first row, you should have to be able to squash all the comments I wrote
+
+97
+00:06:23,000 --> 00:06:27,000
+as letter near to commit s stands for squash.
+
+98
+00:06:28,000 --> 00:06:30,000
+And in case you forgot, you can find other shorthands here.
+
+99
+00:06:31,000 --> 00:06:38,000
+I press control and ask to save the file and close it now and ask my I to address commit message.
+
+100
+00:06:39,000 --> 00:06:42,000
+I see the command lines and commit messages of my other comments.
+
+101
+00:06:43,000 --> 00:06:47,000
+Let me clean this up a bit and leave the one message which I'd like to keep.
+
+102
+00:06:47,000 --> 00:06:51,000
+In addition to this one I want to add a few words is styled.
+
+103
+00:06:52,000 --> 00:06:54,000
+I save the file and close it.
+
+104
+00:06:54,000 --> 00:06:56,000
+I see a message that I successfully replaced.
+
+105
+00:06:57,000 --> 00:06:59,000
+What else potentially might happen here?
+
+106
+00:06:59,000 --> 00:07:06,000
+Potentially you can see a message about much conflict during are basin similar to the one you saw in
+
+107
+00:07:06,000 --> 00:07:07,000
+previous lesson.
+
+108
+00:07:07,000 --> 00:07:13,000
+Take into account you combine comments that might be merged conflicts, but you don't really know how
+
+109
+00:07:13,000 --> 00:07:15,000
+to deal with conflicts during the invasion.
+
+110
+00:07:15,000 --> 00:07:20,000
+Since we showed this in the previous lesson, let's check our command history now.
+
+111
+00:07:20,000 --> 00:07:22,000
+Get log dash three.
+
+112
+00:07:23,000 --> 00:07:27,000
+Great, you can see our comment was updated message and pay attention.
+
+113
+00:07:27,000 --> 00:07:34,000
+You took some if checksum is different, your you know, that pushed the remote repository will be rejected.
+
+114
+00:07:34,000 --> 00:07:39,000
+Beside our audit committee here, you can see all the comments from the remote master branch.
+
+115
+00:07:39,000 --> 00:07:45,000
+And we can see here our chametz, where we adjusted Susanne's file because they're mounted.
+
+116
+00:07:45,000 --> 00:07:47,000
+But the changes are in place.
+
+117
+00:07:47,000 --> 00:07:55,000
+We can open our chasez file just to check this Nuna styles, Desh, Castle, Dot to assess and find
+
+118
+00:07:55,000 --> 00:07:56,000
+that newlines.
+
+119
+00:07:56,000 --> 00:08:00,000
+Edit editing first commit and new line so that you're in the second place.
+
+120
+00:08:00,000 --> 00:08:04,000
+We can count number of new lines, but I believe it is even visually obvious.
+
+121
+00:08:05,000 --> 00:08:10,000
+We did all we wanted and you already know that in case there is a difference between comment history
+
+122
+00:08:10,000 --> 00:08:16,000
+and my local branch and remote branch, we need to for update our remote repository and unpressed lesson
+
+123
+00:08:16,000 --> 00:08:18,000
+learned best practices.
+
+124
+00:08:18,000 --> 00:08:23,000
+And we are going to use force with at least now used brute force with less.
+
+125
+00:08:23,000 --> 00:08:28,000
+We added additional changes and combine them in one snapshot and updated our budget request.
+
+126
+00:08:29,000 --> 00:08:33,000
+This will make you happy on your future project, I promise you.
+
+127
+00:08:33,000 --> 00:08:36,000
+Now let's recap what we have learned today.
+
+128
+00:08:36,000 --> 00:08:39,000
+In this lesson we learned what interactive rebase is.
+
+129
+00:08:39,000 --> 00:08:42,000
+You learn how to start interactive replays.
+
+130
+00:08:42,000 --> 00:08:48,000
+You saw how you can change any commitments that in your repository after this lesson, you also know
+
+131
+00:08:48,000 --> 00:08:50,000
+how to combine few comments together.
+
+132
+00:08:51,000 --> 00:08:54,000
+We learned best practices of working with Gaede today.
+
+133
+00:08:55,000 --> 00:08:56,000
+That's all for now.
+
+134
+00:08:56,000 --> 00:08:58,000
+Thanks a lot for your attention.
+
+135
+00:08:58,000 --> 00:08:59,000
+See you in the next lesson.
+

17 - GIT/015 Git reset_en.srt

@@ -0,0 +1,656 @@
+1
+00:00:06,000 --> 00:00:10,000
+Hello, dear students, in this lesson, we are going to learn in detail what is Guter said command
+
+2
+00:00:10,000 --> 00:00:12,000
+and how we can use it.
+
+3
+00:00:12,000 --> 00:00:17,000
+We'll start from the problem statement and when we might want to use it afterwards.
+
+4
+00:00:17,000 --> 00:00:21,000
+We'll learn in theory how it works to understand how users networks will.
+
+5
+00:00:21,000 --> 00:00:29,000
+Compared with Check-Out Command, we'll use three different modes how to reset my work served mixed
+
+6
+00:00:29,000 --> 00:00:29,000
+and hard.
+
+7
+00:00:30,000 --> 00:00:31,000
+Besides a series overview.
+
+8
+00:00:31,000 --> 00:00:32,000
+One real example.
+
+9
+00:00:32,000 --> 00:00:36,000
+I'm going to show you how you might use this command in your repository.
+
+10
+00:00:36,000 --> 00:00:37,000
+Let's start.
+
+11
+00:00:38,000 --> 00:00:41,000
+So why do you need to use get reset command, get reset.
+
+12
+00:00:41,000 --> 00:00:45,000
+Command is a really powerful tool that will help you to undo changes.
+
+13
+00:00:46,000 --> 00:00:52,000
+It might happen that you created snapshots that you don't need anymore, or probably for some reasons
+
+14
+00:00:52,000 --> 00:00:57,000
+you want to remove commands from your local branch, but you don't want to remove changes from your
+
+15
+00:00:57,000 --> 00:01:00,000
+working directory for such cases.
+
+16
+00:01:00,000 --> 00:01:00,000
+Get reset.
+
+17
+00:01:00,000 --> 00:01:02,000
+Command might be used.
+
+18
+00:01:03,000 --> 00:01:05,000
+You can find tutorials on the Internet.
+
+19
+00:01:05,000 --> 00:01:10,000
+But in my opinion, they're really hard to understand for the people who have never had experience with
+
+20
+00:01:10,000 --> 00:01:10,000
+it.
+
+21
+00:01:11,000 --> 00:01:16,000
+That's why in this lesson, I will try to explain this topic from the practical point of view to help
+
+22
+00:01:16,000 --> 00:01:20,000
+you understand the topic better to understand how to reset command work.
+
+23
+00:01:20,000 --> 00:01:22,000
+Let's compare it with Check-Out Command.
+
+24
+00:01:23,000 --> 00:01:29,000
+Here's our Master Branch and here's our head pointer that points to the latest snapshot on this branch.
+
+25
+00:01:29,000 --> 00:01:35,000
+So what happened when we call you checkout command, when we try to switch to another commit?
+
+26
+00:01:36,000 --> 00:01:41,000
+We can execute Gitche called command with the region, checksum where we want to switch our head pointer
+
+27
+00:01:42,000 --> 00:01:48,000
+in this particular scenario, if checksum is me, then I can move head pointer by executing command
+
+28
+00:01:48,000 --> 00:01:53,000
+Check-Out B But the master branch is still pointing out to the latest command here.
+
+29
+00:01:54,000 --> 00:01:59,000
+If you remember, during one of our lessons we discussed Detached Heads State.
+
+30
+00:01:59,000 --> 00:02:02,000
+This is exactly the scenario of detached head.
+
+31
+00:02:02,000 --> 00:02:06,000
+So what does research come and do that is different from Chicot?
+
+32
+00:02:06,000 --> 00:02:07,000
+Come on.
+
+33
+00:02:08,000 --> 00:02:10,000
+In the case I will use gets reset command.
+
+34
+00:02:10,000 --> 00:02:16,000
+We check some of the specific revision that will move both head pointer and current branch pointer to
+
+35
+00:02:16,000 --> 00:02:17,000
+the specific revision.
+
+36
+00:02:18,000 --> 00:02:19,000
+That's what it always does.
+
+37
+00:02:19,000 --> 00:02:22,000
+No matter what option will be used with reset command.
+
+38
+00:02:23,000 --> 00:02:25,000
+Can you see the difference on this visualization?
+
+39
+00:02:26,000 --> 00:02:29,000
+Hope it is clear now what reset command does.
+
+40
+00:02:29,000 --> 00:02:36,000
+But besides updating of command pointers like head pointer and branch pointer, reset command will also
+
+41
+00:02:36,000 --> 00:02:40,000
+update the state of our staging area and update the state of our country.
+
+42
+00:02:40,000 --> 00:02:42,000
+That is our files in our file system.
+
+43
+00:02:43,000 --> 00:02:48,000
+Updates in the staging area and our country will be different depending on what mode of reset we are
+
+44
+00:02:48,000 --> 00:02:51,000
+going to use as a result from agenda.
+
+45
+00:02:51,000 --> 00:02:55,000
+There are three possible modes soft, mixed and hard.
+
+46
+00:02:56,000 --> 00:03:00,000
+Let's learn right now what will happen in case we reset in soft mode.
+
+47
+00:03:00,000 --> 00:03:06,000
+If we use get reset with soft option, we still move ahead and branch pointers to the specific region
+
+48
+00:03:06,000 --> 00:03:07,000
+and that's it.
+
+49
+00:03:07,000 --> 00:03:13,000
+Nice and above that changes from your working tree will be there and in the staging area.
+
+50
+00:03:14,000 --> 00:03:20,000
+In simple words, the changes that you did in files before reset and commit these changes, you will
+
+51
+00:03:20,000 --> 00:03:22,000
+be present in files of your project.
+
+52
+00:03:22,000 --> 00:03:28,000
+Moreover, these changes will be in the staging area in case after asset in soft mode.
+
+53
+00:03:28,000 --> 00:03:30,000
+You would call your status command.
+
+54
+00:03:30,000 --> 00:03:34,000
+You would find all your changes added to the staging area in green color.
+
+55
+00:03:35,000 --> 00:03:40,000
+Execution of command is going to lead you directly to the state where you were before 7:00.
+
+56
+00:03:41,000 --> 00:03:46,000
+Here on this slide, you can see that soft mode keeps all changes in the staging area.
+
+57
+00:03:46,000 --> 00:03:50,000
+In case you are going to use mixed option, it is similar to softwoods.
+
+58
+00:03:50,000 --> 00:03:57,000
+Only one difference changes still will be present in the working directory, but they won't be present
+
+59
+00:03:57,000 --> 00:03:58,000
+in the staging area.
+
+60
+00:03:58,000 --> 00:04:04,000
+In simple words, you still will be able to find the changes in files, but when you will call git status,
+
+61
+00:04:05,000 --> 00:04:08,000
+you're going to see that all changes are not added to the staging area.
+
+62
+00:04:09,000 --> 00:04:15,000
+You would need to perform it add and after that you commit command in case you want to restore the state
+
+63
+00:04:15,000 --> 00:04:20,000
+before setting the previous two options you might want to use when you kind of okay with changes that
+
+64
+00:04:20,000 --> 00:04:21,000
+you have done.
+
+65
+00:04:21,000 --> 00:04:24,000
+But you have to do some modifications in the good history.
+
+66
+00:04:24,000 --> 00:04:26,000
+The first option for that is really hard.
+
+67
+00:04:27,000 --> 00:04:32,000
+This is the most direct and dangerous option that is frequently used after executing this reset.
+
+68
+00:04:32,000 --> 00:04:34,000
+Command was a hard option.
+
+69
+00:04:34,000 --> 00:04:41,000
+Get will make sure that your staging area and are working very much that of the specific commit in simple
+
+70
+00:04:41,000 --> 00:04:48,000
+words, your file system will be the same as it was after which you specified in reset command when
+
+71
+00:04:48,000 --> 00:04:49,000
+this mode is needed.
+
+72
+00:04:49,000 --> 00:04:55,000
+Personally, I used this command a lot when I realized that I messed up completely the state of my files
+
+73
+00:04:55,000 --> 00:04:59,000
+and I want to get everything back as it was when it worked, at least somehow.
+
+74
+00:05:00,000 --> 00:05:03,000
+Sometimes you might want to reset the state of some specific revision.
+
+75
+00:05:04,000 --> 00:05:09,000
+Probably you want to reset state of your local repository to the state that you have in the remote repository.
+
+76
+00:05:09,000 --> 00:05:12,000
+You might want to do so in case something went wrong.
+
+77
+00:05:12,000 --> 00:05:15,000
+During The Amazing today you're in the demo.
+
+78
+00:05:15,000 --> 00:05:18,000
+I will show you how to reset your changes in different modes.
+
+79
+00:05:19,000 --> 00:05:24,000
+Now, when you understood the theory, let's practice a bit and I'll show you how you can use gets reset
+
+80
+00:05:24,000 --> 00:05:25,000
+command in different modes.
+
+81
+00:05:26,000 --> 00:05:27,000
+We are on the Master Branch.
+
+82
+00:05:27,000 --> 00:05:32,000
+Let's check our gate history gate log dash three.
+
+83
+00:05:32,000 --> 00:05:35,000
+Here is a command that we did during this course.
+
+84
+00:05:35,000 --> 00:05:39,000
+You remember we added stock management service and created separate snapshots for that.
+
+85
+00:05:40,000 --> 00:05:44,000
+Afterwards we credit card management service file and created separate snapshots for that.
+
+86
+00:05:45,000 --> 00:05:53,000
+And after that I did create HTML file homeport HTML for our lessons to understand much conflict topic.
+
+87
+00:05:53,000 --> 00:05:54,000
+Remember that.
+
+88
+00:05:54,000 --> 00:06:00,000
+Let me show you, for example, that after soft reset to the state of the Stock Management Command Card
+
+89
+00:06:00,000 --> 00:06:06,000
+Management Service and home e-mail are still present in the country, but the state of the branch and
+
+90
+00:06:06,000 --> 00:06:07,000
+head pointer is different.
+
+91
+00:06:08,000 --> 00:06:17,000
+Guter said was option soft e 71, A five, b, I entered first characters of this commit and press enter.
+
+92
+00:06:17,000 --> 00:06:21,000
+Let's check our comment history to understand where we are now.
+
+93
+00:06:21,000 --> 00:06:22,000
+Get lost there.
+
+94
+00:06:22,000 --> 00:06:28,000
+Three You see here in parenthesis that our head and master pointers are on this comment.
+
+95
+00:06:29,000 --> 00:06:36,000
+Let me check its status and its status and you can see the two files from the documents are present
+
+96
+00:06:36,000 --> 00:06:42,000
+in my file system and automatically added to the staging area to return my project to the state where
+
+97
+00:06:42,000 --> 00:06:43,000
+it was before the reset.
+
+98
+00:06:43,000 --> 00:06:50,000
+But with a new command, I have to come them one more time, get command with option and court management
+
+99
+00:06:50,000 --> 00:06:51,000
+and home HMO.
+
+100
+00:06:52,000 --> 00:06:55,000
+And we created new command with these changes.
+
+101
+00:06:55,000 --> 00:07:02,000
+Now I want to demo to you makes the more me find commands that we recently used and just change it a
+
+102
+00:07:02,000 --> 00:07:02,000
+bit.
+
+103
+00:07:03,000 --> 00:07:03,000
+Here it is.
+
+104
+00:07:04,000 --> 00:07:07,000
+Let me removed soft here, by the way.
+
+105
+00:07:07,000 --> 00:07:08,000
+Mixed mode is a default.
+
+106
+00:07:09,000 --> 00:07:12,000
+That means you shouldn't necessarily write me here.
+
+107
+00:07:13,000 --> 00:07:15,000
+You can just remove any options here.
+
+108
+00:07:15,000 --> 00:07:18,000
+That would mean resetting in the default mixed mode.
+
+109
+00:07:18,000 --> 00:07:22,000
+Let me check it lock now it log Destry.
+
+110
+00:07:22,000 --> 00:07:28,000
+I'm on the committee where I wanted to be and like check status now get status.
+
+111
+00:07:28,000 --> 00:07:33,000
+And you can see that files are present in my work entry in my file system, but they are not in the
+
+112
+00:07:33,000 --> 00:07:34,000
+staging area.
+
+113
+00:07:35,000 --> 00:07:38,000
+Can you understand the difference between soft and mixed mode now?
+
+114
+00:07:39,000 --> 00:07:44,000
+The return the previous state I should execute get at DOD command and after that it changes.
+
+115
+00:07:45,000 --> 00:07:48,000
+Let's use the same messages previously for the sake of the demo.
+
+116
+00:07:49,000 --> 00:07:56,000
+Awesome, and let me show you the last but not the least option, hard lessons said enhancement to this
+
+117
+00:07:56,000 --> 00:07:59,000
+commit spaces are added to the hello world.
+
+118
+00:07:59,000 --> 00:08:06,000
+While we should see how the state of our file system will be different from that e-mail, card management
+
+119
+00:08:06,000 --> 00:08:09,000
+servers and stock management service files would disappear.
+
+120
+00:08:10,000 --> 00:08:14,000
+Let's reset resorption heart two six seven two six F..
+
+121
+00:08:15,000 --> 00:08:16,000
+Let's check in with history now.
+
+122
+00:08:17,000 --> 00:08:18,000
+Get logged three.
+
+123
+00:08:19,000 --> 00:08:25,000
+OK, our head pointer and branch are pointing to the committee that we expect, but what is with our
+
+124
+00:08:25,000 --> 00:08:26,000
+filesystem now?
+
+125
+00:08:27,000 --> 00:08:34,000
+It's status and we can see that there is nothing to commit, and that is my voluntary claim, I'm in
+
+126
+00:08:34,000 --> 00:08:36,000
+the Israeli folder right now.
+
+127
+00:08:36,000 --> 00:08:44,000
+Let me check the state of the file system unless there shall we can see that I have only discount completion
+
+128
+00:08:44,000 --> 00:08:45,000
+service and hello, world file.
+
+129
+00:08:45,000 --> 00:08:50,000
+I do not have Nasacort nor stock folders where my other files were stored.
+
+130
+00:08:51,000 --> 00:08:54,000
+Now you can see how it was that was hard option, Kenora said.
+
+131
+00:08:54,000 --> 00:08:56,000
+The state of the file system.
+
+132
+00:08:56,000 --> 00:08:59,000
+One more trick, probably in some lessons.
+
+133
+00:08:59,000 --> 00:09:05,000
+You saw that I researched state of the branch without reference to the specific checks, but using relative
+
+134
+00:09:05,000 --> 00:09:07,000
+navigation from the head pointer.
+
+135
+00:09:07,000 --> 00:09:09,000
+Let me show you one more time.
+
+136
+00:09:10,000 --> 00:09:14,000
+Get reset with option heart had to the three.
+
+137
+00:09:14,000 --> 00:09:20,000
+You can see how I can move that Anabranch pointer to three cm is back from the point where I was.
+
+138
+00:09:20,000 --> 00:09:21,000
+This is pretty convenient.
+
+139
+00:09:21,000 --> 00:09:25,000
+As for me, probably you would also use this variation of reset command.
+
+140
+00:09:26,000 --> 00:09:33,000
+And one more real life scenario, imagine that you wanted either to squash commits or a message or something
+
+141
+00:09:33,000 --> 00:09:36,000
+else went wrong during the invasion or during the development.
+
+142
+00:09:36,000 --> 00:09:41,000
+And you want to reset the state of your working tree, your file system, as it is in a remote repository
+
+143
+00:09:41,000 --> 00:09:42,000
+right now.
+
+144
+00:09:43,000 --> 00:09:49,000
+What I recommend you to do, the first thing that I always do is execution of each command with option
+
+145
+00:09:49,000 --> 00:09:52,000
+like this need fetch resorption.
+
+146
+00:09:52,000 --> 00:09:59,000
+All this is just to make sure that you fetch the latest state of the remote repository after that reset
+
+147
+00:09:59,000 --> 00:10:02,000
+with the hard option to the State of Origin branch.
+
+148
+00:10:03,000 --> 00:10:09,000
+In this particular case, we played with our master branch and I want to restore the state of our region.
+
+149
+00:10:09,000 --> 00:10:14,000
+Must have branch reset with option, heart or region slash master.
+
+150
+00:10:14,000 --> 00:10:17,000
+And you can see that I'm on the latest commit right now.
+
+151
+00:10:18,000 --> 00:10:20,000
+So there you saw that in reset command.
+
+152
+00:10:20,000 --> 00:10:26,000
+You can use chametz checksum, relative amount of comments from the head pointer and even specific branch,
+
+153
+00:10:27,000 --> 00:10:27,000
+I believe.
+
+154
+00:10:27,000 --> 00:10:31,000
+Now you know about reset command even more than some senior software engineers.
+
+155
+00:10:32,000 --> 00:10:33,000
+Hope you enjoyed the lesson.
+
+156
+00:10:34,000 --> 00:10:36,000
+Let's recap what we have learned today.
+
+157
+00:10:37,000 --> 00:10:40,000
+Today, we learned what is a good reset command and when we can use it.
+
+158
+00:10:41,000 --> 00:10:44,000
+We understand the difference between reaching out and gives reset command.
+
+159
+00:10:45,000 --> 00:10:51,000
+You learn three modes of reset command, soft, mixed and hard on the real example.
+
+160
+00:10:51,000 --> 00:10:55,000
+You saw how to reset state of the branch if you coming back from the head pointer or to the specific
+
+161
+00:10:55,000 --> 00:10:56,000
+command.
+
+162
+00:10:56,000 --> 00:11:01,000
+Also, you learned how to reset state of the branch to the state of the branch in the remote repository.
+
+163
+00:11:02,000 --> 00:11:05,000
+That's all what I planned to talk about in this lesson with you.
+
+164
+00:11:05,000 --> 00:11:08,000
+Thanks a lot for your attention and see you in the next lesson.
+

17 - GIT/016 Git stash_en.srt

@@ -0,0 +1,728 @@
+1
+00:00:06,000 --> 00:00:09,000
+Hello there, students in this class and we are going to lunch with you get Stasch command.
+
+2
+00:00:09,000 --> 00:00:12,000
+I'm going to tell you when you might need to use it.
+
+3
+00:00:12,000 --> 00:00:16,000
+You'll understand how to reapply changes from your stash on real examples.
+
+4
+00:00:16,000 --> 00:00:21,000
+I will show you how to manage multiple stashes and even how to create a branch from your stash.
+
+5
+00:00:21,000 --> 00:00:25,000
+And also, we are going to run different commands that will allow you to clean your stash and to perform
+
+6
+00:00:25,000 --> 00:00:27,000
+as operations with it.
+
+7
+00:00:27,000 --> 00:00:33,000
+Let's start first of all, let's understand potential problems at stash command may help us to resolve.
+
+8
+00:00:33,000 --> 00:00:39,000
+Imagine that you are sitting at your computer and work on some task and all of a sudden you receive
+
+9
+00:00:39,000 --> 00:00:40,000
+a call from your manager.
+
+10
+00:00:40,000 --> 00:00:46,000
+Your manager screams that you urgently need to fix some other thing or you have to start work on the
+
+11
+00:00:46,000 --> 00:00:47,000
+other task immediately.
+
+12
+00:00:47,000 --> 00:00:49,000
+But it didn't finish your current task.
+
+13
+00:00:49,000 --> 00:00:53,000
+Your manager told you that you have to give up everything and start work on the new task.
+
+14
+00:00:54,000 --> 00:00:59,000
+The state of a file system doesn't allow you to create a committee right now, probably because you
+
+15
+00:00:59,000 --> 00:01:04,000
+even can't build your project successfully or you are just in the middle of something important to finish.
+
+16
+00:01:04,000 --> 00:01:09,000
+And it looks like that you have to put all your changes aside to get back to them later.
+
+17
+00:01:10,000 --> 00:01:15,000
+Hope that you understood the problem and real life case that might happen with you almost on a daily
+
+18
+00:01:15,000 --> 00:01:15,000
+basis.
+
+19
+00:01:16,000 --> 00:01:23,000
+But how to address this issue with the help of the Get Eustache Command will help us with this station.
+
+20
+00:01:23,000 --> 00:01:30,000
+Take the state of a working directory that is humidified direct files, stage changes and saves it on
+
+21
+00:01:30,000 --> 00:01:35,000
+a stack of unfinished changes that you can apply at any time, even on different branch.
+
+22
+00:01:36,000 --> 00:01:37,000
+What a staircase.
+
+23
+00:01:37,000 --> 00:01:38,000
+I will explain a bit later.
+
+24
+00:01:39,000 --> 00:01:39,000
+Nonwork.
+
+25
+00:01:40,000 --> 00:01:45,000
+I believe that the best way to understand how Eustache Command works is to show it to you in it.
+
+26
+00:01:45,000 --> 00:01:49,000
+But I am a master branch right now and my work in tree is clean.
+
+27
+00:01:49,000 --> 00:01:53,000
+Let's imagine I'm in the process of implementation of some important task.
+
+28
+00:01:53,000 --> 00:02:00,000
+I create a new branch and get to reach resorption c a three zero six important task.
+
+29
+00:02:00,000 --> 00:02:08,000
+OK, and being on this branch in SASE folder, I modified home HTML file to not switch the windows between
+
+30
+00:02:08,000 --> 00:02:09,000
+different code editors.
+
+31
+00:02:09,000 --> 00:02:15,000
+Let me do small changes right here in the terminal using nano text editor nano web content slash home
+
+32
+00:02:15,000 --> 00:02:17,000
+dot html.
+
+33
+00:02:17,000 --> 00:02:19,000
+I added some important changes here.
+
+34
+00:02:20,000 --> 00:02:24,000
+Be some important line tag is closed.
+
+35
+00:02:24,000 --> 00:02:31,000
+After I did all my changes, I saved a file and now I received a message from my manager who is in panic
+
+36
+00:02:31,000 --> 00:02:34,000
+and asks me to start work on the super important task.
+
+37
+00:02:35,000 --> 00:02:39,000
+I don't need changes from home HTML file that we have just created.
+
+38
+00:02:39,000 --> 00:02:41,000
+Deunan another task implementation.
+
+39
+00:02:42,000 --> 00:02:50,000
+Let me check the status of my branch, get status and you can see I have one file modified and currently
+
+40
+00:02:50,000 --> 00:02:53,000
+it is in the state one creating snapshot with it doesn't make a lot of sense.
+
+41
+00:02:54,000 --> 00:02:56,000
+So I will put a temporary in my stash.
+
+42
+00:02:57,000 --> 00:02:59,000
+How simply by executing the next command.
+
+43
+00:03:00,000 --> 00:03:02,000
+Eustache Great.
+
+44
+00:03:02,000 --> 00:03:04,000
+Now our changes are in Stasch.
+
+45
+00:03:04,000 --> 00:03:09,000
+Let's check status one more time and you can see that right now it is nothing to commit.
+
+46
+00:03:10,000 --> 00:03:13,000
+But now I can be sure that my changes won't disappear.
+
+47
+00:03:14,000 --> 00:03:18,000
+I'm returning to the Master Branch to create the new branch uSwitch Dash.
+
+48
+00:03:19,000 --> 00:03:25,000
+Here I create a new branch, uSwitch, which resorption CGA three 07.
+
+49
+00:03:25,000 --> 00:03:26,000
+Super important task.
+
+50
+00:03:27,000 --> 00:03:31,000
+OK, and now I can continue work on my new important task.
+
+51
+00:03:31,000 --> 00:03:34,000
+My changes that are currently in Stasch are not present on this branch.
+
+52
+00:03:34,000 --> 00:03:35,000
+Let me show you this.
+
+53
+00:03:36,000 --> 00:03:39,000
+None of Condon's home, not HTML.
+
+54
+00:03:39,000 --> 00:03:48,000
+And we can find our important line here cuz now let's imagine that you realize that you need those changes
+
+55
+00:03:48,000 --> 00:03:49,000
+here and you need them back.
+
+56
+00:03:50,000 --> 00:03:52,000
+How get your changes back from Stasch.
+
+57
+00:03:52,000 --> 00:03:56,000
+You need to apply changes from your stash to do this.
+
+58
+00:03:56,000 --> 00:03:57,000
+Let's use the next command.
+
+59
+00:03:57,000 --> 00:03:59,000
+Eustache apply.
+
+60
+00:03:59,000 --> 00:04:06,000
+And instantly you see the status of the branch and indications and home e-mail file is modified, let
+
+61
+00:04:06,000 --> 00:04:07,000
+me open it to double check.
+
+62
+00:04:08,000 --> 00:04:11,000
+Yes, I see my important line here.
+
+63
+00:04:11,000 --> 00:04:12,000
+Awesome.
+
+64
+00:04:13,000 --> 00:04:18,000
+Now, important information about Stasch, this command, great stack of changes.
+
+65
+00:04:18,000 --> 00:04:21,000
+They understand how a stack of changes may look like.
+
+66
+00:04:21,000 --> 00:04:22,000
+Let me show you quickly.
+
+67
+00:04:23,000 --> 00:04:30,000
+In computer science, tech is an abstract data type that serves as a collection of elements, it works
+
+68
+00:04:30,000 --> 00:04:31,000
+according to leave for principle.
+
+69
+00:04:32,000 --> 00:04:35,000
+One more fancy word what does leave or stand for?
+
+70
+00:04:36,000 --> 00:04:39,000
+Leifur is an acronym from Last In, First Out.
+
+71
+00:04:40,000 --> 00:04:45,000
+This is a method of storing data in data structures, according to which the last element get into the
+
+72
+00:04:45,000 --> 00:04:48,000
+container, leaves the containers the first.
+
+73
+00:04:48,000 --> 00:04:51,000
+And on the screen you can see visualization of Steck.
+
+74
+00:04:51,000 --> 00:04:55,000
+Imagine that each element here is a separate batch of changes.
+
+75
+00:04:56,000 --> 00:05:00,000
+When you use Stasch command, your changes are on the bottom of this container.
+
+76
+00:05:01,000 --> 00:05:06,000
+When you use against apply command, the changes from top of the stack apply to your branch.
+
+77
+00:05:07,000 --> 00:05:12,000
+And if you use git stash command multiple times, the new changes will be on top.
+
+78
+00:05:13,000 --> 00:05:14,000
+Does it make sense?
+
+79
+00:05:15,000 --> 00:05:21,000
+Now imagine that you used Stasch command multiple times and you have a lot of changes in your Stasch
+
+80
+00:05:21,000 --> 00:05:24,000
+stack, how to view all changes that you have in your stack of changes.
+
+81
+00:05:25,000 --> 00:05:27,000
+Let me show you the list.
+
+82
+00:05:27,000 --> 00:05:28,000
+All the changes that you have in your stack.
+
+83
+00:05:28,000 --> 00:05:31,000
+Use the next command git stash list.
+
+84
+00:05:32,000 --> 00:05:36,000
+And specially for this lesson, I prepared a few items to have multiple elements here.
+
+85
+00:05:37,000 --> 00:05:41,000
+You can see that our last stash has index zero and it is on the top of our stack.
+
+86
+00:05:42,000 --> 00:05:48,000
+That means you can apply it on different branches, but probably you might be wondering how to apply.
+
+87
+00:05:48,000 --> 00:05:51,000
+Are the changes from the stack for the sake of the demo?
+
+88
+00:05:51,000 --> 00:05:52,000
+Let me apply changes from this stack.
+
+89
+00:05:52,000 --> 00:05:59,000
+Was the indexed One Eustache apply and after that I will use the name of the stash that is specified
+
+90
+00:05:59,000 --> 00:06:03,000
+here, stash add and one in curly brackets.
+
+91
+00:06:04,000 --> 00:06:10,000
+Before I press and I want to warn you that you're going to see error message hypocenter.
+
+92
+00:06:10,000 --> 00:06:13,000
+And as I promised, here is the error.
+
+93
+00:06:13,000 --> 00:06:16,000
+Don't worry, everything is under control.
+
+94
+00:06:16,000 --> 00:06:21,000
+I did this on purpose to show you this error message that you may see some time get.
+
+95
+00:06:21,000 --> 00:06:26,000
+Sometimes we'll show you this message to warn you that your changes might be overwritten after some
+
+96
+00:06:26,000 --> 00:06:27,000
+specific operation.
+
+97
+00:06:27,000 --> 00:06:31,000
+And this is one more case to Eustache as a temporary storage for your changes.
+
+98
+00:06:32,000 --> 00:06:34,000
+I already have these changes in my stash.
+
+99
+00:06:34,000 --> 00:06:39,000
+So let me just come in, then get dash a dash and commit.
+
+100
+00:06:40,000 --> 00:06:45,000
+Sorry about this message, just don't want to spend time on the details that we already discussed.
+
+101
+00:06:46,000 --> 00:06:50,000
+Hope you understand that such a meaningful message is not the best practice.
+
+102
+00:06:50,000 --> 00:06:54,000
+And I use it only for the sake of the drama to not lose the focus from the Stasch.
+
+103
+00:06:54,000 --> 00:06:56,000
+Come on now.
+
+104
+00:06:56,000 --> 00:07:00,000
+When I created the snapshot, let me try to apply one more time.
+
+105
+00:07:00,000 --> 00:07:04,000
+Are the changes from the Stasch and you see that some changes were applied here.
+
+106
+00:07:05,000 --> 00:07:11,000
+Namely, Log-in says, as file was removed and changes in home each time on file were also applied.
+
+107
+00:07:12,000 --> 00:07:16,000
+There is even a conflict in this file since it was modified in different versions.
+
+108
+00:07:17,000 --> 00:07:21,000
+You just have to open this file and to resolve conflicts for the sake of the demo.
+
+109
+00:07:21,000 --> 00:07:27,000
+Let me reset the state of the current branch to its original state, yet reset resorption heart to the
+
+110
+00:07:27,000 --> 00:07:28,000
+head pointer.
+
+111
+00:07:29,000 --> 00:07:31,000
+Let's talk about another problem.
+
+112
+00:07:31,000 --> 00:07:33,000
+Do you remember what is in my stash list?
+
+113
+00:07:33,000 --> 00:07:36,000
+Let me show it one more time yet stash lists.
+
+114
+00:07:37,000 --> 00:07:42,000
+How do you think will I remember that that changes and how much time I'll file in the stash tomorrow
+
+115
+00:07:43,000 --> 00:07:44,000
+or in a month.
+
+116
+00:07:44,000 --> 00:07:48,000
+That's why it usually does a good practice to give a name to each stash.
+
+117
+00:07:49,000 --> 00:07:51,000
+Let me do some changes in the repository.
+
+118
+00:07:51,000 --> 00:07:59,000
+For example, let me remove login scissors file ram style slash logging that says there is a standard
+
+119
+00:07:59,000 --> 00:08:02,000
+command in Linux terminals to remove files.
+
+120
+00:08:03,000 --> 00:08:10,000
+Let me stash my current changes with a specific message you'd stash safe logins, he says is removed
+
+121
+00:08:11,000 --> 00:08:12,000
+and lets presenta.
+
+122
+00:08:12,000 --> 00:08:18,000
+Now, when I will see the stash in the future in my specialist, I will instantly understand what changes
+
+123
+00:08:18,000 --> 00:08:20,000
+it contains existentialists.
+
+124
+00:08:21,000 --> 00:08:25,000
+And here I can see my last stash and it is on the top of the stack.
+
+125
+00:08:25,000 --> 00:08:26,000
+Great.
+
+126
+00:08:27,000 --> 00:08:33,000
+OK, now let me explain you one more thing, probably you noticed that I applied different stashes,
+
+127
+00:08:33,000 --> 00:08:39,000
+but they're still in my stack how to apply stash and remove it from the stack for doing this.
+
+128
+00:08:39,000 --> 00:08:42,000
+You have to use Bob Camonte instead of apply like this.
+
+129
+00:08:42,000 --> 00:08:48,000
+Eustache Pop, we see that I applied my last stash and login success is removed.
+
+130
+00:08:48,000 --> 00:08:50,000
+Let me check my specialist now.
+
+131
+00:08:51,000 --> 00:08:54,000
+And now you can see that it has disappeared from here.
+
+132
+00:08:55,000 --> 00:08:56,000
+Let's move on.
+
+133
+00:08:56,000 --> 00:09:02,000
+One more thing that we didn't discuss yet is that you can stash only changes that are in the staging
+
+134
+00:09:02,000 --> 00:09:06,000
+area or changes that were done in files that are tracked by it.
+
+135
+00:09:07,000 --> 00:09:10,000
+Imagine that we created a file and after that we were interrupted.
+
+136
+00:09:11,000 --> 00:09:12,000
+We have to stash it.
+
+137
+00:09:12,000 --> 00:09:19,000
+Let me quickly create a file here, touch some important file dot java right now.
+
+138
+00:09:19,000 --> 00:09:21,000
+This file isn't tracked by yet.
+
+139
+00:09:21,000 --> 00:09:22,000
+Let me show you this.
+
+140
+00:09:23,000 --> 00:09:23,000
+It's status.
+
+141
+00:09:24,000 --> 00:09:29,000
+And in case I would try to suggest changes on the removal of Logan's SS will be stored.
+
+142
+00:09:30,000 --> 00:09:32,000
+Let me prove you this, Eustache.
+
+143
+00:09:33,000 --> 00:09:40,000
+And now let's check your status one more time and see that my new file is still in Ontrack State and
+
+144
+00:09:40,000 --> 00:09:43,000
+is not in the Stasch, how to add it to the stash?
+
+145
+00:09:44,000 --> 00:09:46,000
+We have to use a special option for that.
+
+146
+00:09:46,000 --> 00:09:49,000
+Let me show you need Stasch with option U.
+
+147
+00:09:50,000 --> 00:09:52,000
+U stands for untracked files.
+
+148
+00:09:52,000 --> 00:09:54,000
+Instead of you, you can use a option.
+
+149
+00:09:55,000 --> 00:09:58,000
+A stands for all besides untracked files.
+
+150
+00:09:58,000 --> 00:10:02,000
+It would also stash files that are ignored according to our Getting Your File.
+
+151
+00:10:03,000 --> 00:10:07,000
+But I doubt that you would ever want it to include ignored files to your stash.
+
+152
+00:10:07,000 --> 00:10:08,000
+That's why.
+
+153
+00:10:08,000 --> 00:10:12,000
+Let's use you option here, Hypocenter.
+
+154
+00:10:13,000 --> 00:10:16,000
+Let me check your status now, your status.
+
+155
+00:10:17,000 --> 00:10:17,000
+Awesome.
+
+156
+00:10:18,000 --> 00:10:24,000
+Finally, it looks like our new file was stashed, and now imagine that you want to create a branch
+
+157
+00:10:24,000 --> 00:10:25,000
+from your stash.
+
+158
+00:10:25,000 --> 00:10:31,000
+Imagine that when you finished work on the super important task, you already removed all old branches
+
+159
+00:10:31,000 --> 00:10:32,000
+and you have to create a new one.
+
+160
+00:10:33,000 --> 00:10:41,000
+How to create a new branch from Stash use the next command, Eustache Branch, a three zero seven new.
+
+161
+00:10:42,000 --> 00:10:46,000
+You can specify here any Stasha you would like without specifying Stasha.
+
+162
+00:10:47,000 --> 00:10:53,000
+The first stash from the stack will be used and you see that I have new untracked file on my new branch
+
+163
+00:10:54,000 --> 00:10:56,000
+that also moved me to the new branch.
+
+164
+00:10:57,000 --> 00:11:03,000
+You can see it here in parentheses and what to do in case you don't want to apply your stash, but you
+
+165
+00:11:03,000 --> 00:11:08,000
+just want to remove it, use the next command, get stash, drop.
+
+166
+00:11:08,000 --> 00:11:10,000
+You can specify any stash.
+
+167
+00:11:10,000 --> 00:11:14,000
+I here, for example, stash at zero.
+
+168
+00:11:14,000 --> 00:11:18,000
+Now let's check stash list, new stash list.
+
+169
+00:11:18,000 --> 00:11:22,000
+And you see that our first stash in stack was removed by us.
+
+170
+00:11:25,000 --> 00:11:31,000
+In case you want to clear all stack of stashes, use the next command, get Stasch clear.
+
+171
+00:11:32,000 --> 00:11:38,000
+And in case we would check our specialists, now we are going to see nothing and here is empty list,
+
+172
+00:11:38,000 --> 00:11:39,000
+nothing is here.
+
+173
+00:11:40,000 --> 00:11:44,000
+Great, it looks like that is all what I plan to share with you in this lesson.
+
+174
+00:11:44,000 --> 00:11:46,000
+Let's recap what we have learned today.
+
+175
+00:11:47,000 --> 00:11:50,000
+So today we learned what the stashes now we know how to use stash.
+
+176
+00:11:50,000 --> 00:11:52,000
+Come on, on real examples.
+
+177
+00:11:52,000 --> 00:11:54,000
+We learned how to manage multiple stashes.
+
+178
+00:11:55,000 --> 00:11:59,000
+We learned how to stash direct files and how to clear your stash if needed.
+
+179
+00:11:59,000 --> 00:12:04,000
+We also learned what is the difference between stash supply and stash pop.
+
+180
+00:12:04,000 --> 00:12:05,000
+That's all for now.
+
+181
+00:12:06,000 --> 00:12:07,000
+Thanks a lot for your attention.
+
+182
+00:12:07,000 --> 00:12:09,000
+See you in the next lesson.
+

17 - GIT/017 Restoring lost snapshots in Git git reflog_en.srt

@@ -0,0 +1,412 @@
+1
+00:00:06,000 --> 00:00:06,000
+Hello, Jim.
+
+2
+00:00:06,000 --> 00:00:11,000
+Today, we're going to have super interesting topic and this last one, I'll show you how you can restore
+
+3
+00:00:11,000 --> 00:00:12,000
+literally everything.
+
+4
+00:00:12,000 --> 00:00:18,000
+What was ever present in any snapshot in it, even if it was overwritten, is by force push or hard
+
+5
+00:00:18,000 --> 00:00:19,000
+reset.
+
+6
+00:00:19,000 --> 00:00:22,000
+But I will run such command as gets where flock.
+
+7
+00:00:22,000 --> 00:00:25,000
+We're going to understand when and why we have to use.
+
+8
+00:00:25,000 --> 00:00:30,000
+It will imitate cases when we lost some changes and we need to restore them.
+
+9
+00:00:30,000 --> 00:00:35,000
+After this lesson, you will be able to use reflood command with different options and variations.
+
+10
+00:00:35,000 --> 00:00:42,000
+Like a pro, you are going to learn how to restore lost command in the new branch or reset current branch
+
+11
+00:00:42,000 --> 00:00:43,000
+to the committees that were lost.
+
+12
+00:00:44,000 --> 00:00:49,000
+Let's understand first, why do we need to use lock and what problem it may help us to solve?
+
+13
+00:00:50,000 --> 00:00:55,000
+It may happen that at some point during your journey you may accidentally lose a command.
+
+14
+00:00:55,000 --> 00:01:00,000
+Like I told you before, it may happen during the force delete of your work or during the hard reset
+
+15
+00:01:01,000 --> 00:01:06,000
+or you use interactive rebate's to squash commands and the resolving of conflicts during the invasion
+
+16
+00:01:06,000 --> 00:01:08,000
+went wrong and some changes were lost.
+
+17
+00:01:08,000 --> 00:01:16,000
+So how to get those changes back in if something were ever committed, might be restored, yet won't
+
+18
+00:01:16,000 --> 00:01:21,000
+be able to restore files that were never in the staging area and were never committed before.
+
+19
+00:01:22,000 --> 00:01:26,000
+I suggest that a lot of the kids were locked directly from the practical exercise.
+
+20
+00:01:27,000 --> 00:01:30,000
+Let's start to show you how to restore changes.
+
+21
+00:01:30,000 --> 00:01:32,000
+Let me intentionally lose some data.
+
+22
+00:01:32,000 --> 00:01:34,000
+I'm on the master branch.
+
+23
+00:01:34,000 --> 00:01:35,000
+Let me show you.
+
+24
+00:01:35,000 --> 00:01:38,000
+Let latest Kummetz gate log dash three.
+
+25
+00:01:39,000 --> 00:01:47,000
+Let me Hardell said Doulos commits yet reset hard had yielded to OK the branches reset.
+
+26
+00:01:48,000 --> 00:01:51,000
+Let's check commit history Dedlock.
+
+27
+00:01:52,000 --> 00:01:59,000
+Now we can say that we lost to commit, OK, there is no harm for me to restore the changes from the
+
+28
+00:01:59,000 --> 00:02:05,000
+region branch, but it might happen that a regional branch was also accidentally overwritten or completely
+
+29
+00:02:05,000 --> 00:02:05,000
+removed.
+
+30
+00:02:06,000 --> 00:02:08,000
+You won't believe me, but such cases may happen.
+
+31
+00:02:09,000 --> 00:02:14,000
+At the first glance, it looks like that I only need to remember to check some of the lost comments,
+
+32
+00:02:14,000 --> 00:02:16,000
+but we didn't memorize them.
+
+33
+00:02:16,000 --> 00:02:19,000
+Agree the most complicated in this task to learn.
+
+34
+00:02:19,000 --> 00:02:21,000
+Check some of those comments.
+
+35
+00:02:21,000 --> 00:02:25,000
+And the easiest thing to answer this question is to call it red flag.
+
+36
+00:02:25,000 --> 00:02:27,000
+Come on, what is a red flag?
+
+37
+00:02:28,000 --> 00:02:32,000
+As we are working with gait and movement pointers get silently records.
+
+38
+00:02:32,000 --> 00:02:35,000
+What is our head pointer and how does it look like?
+
+39
+00:02:36,000 --> 00:02:42,000
+That means that each time we are creating a new snapshot or switching branches, the red flag is updated.
+
+40
+00:02:43,000 --> 00:02:49,000
+You can investigate the history of all changes in your repository by executing the next command gateway
+
+41
+00:02:49,000 --> 00:02:49,000
+flock.
+
+42
+00:02:50,000 --> 00:02:56,000
+We can see information about each operation that was done here about each commit, each research on
+
+43
+00:02:56,000 --> 00:02:57,000
+the region must have branch.
+
+44
+00:02:58,000 --> 00:03:02,000
+You can find information here about different branches by the reference in the parentheses.
+
+45
+00:03:02,000 --> 00:03:06,000
+Also, you may find checksum of each state right here.
+
+46
+00:03:06,000 --> 00:03:08,000
+By the way, this is the last program.
+
+47
+00:03:08,000 --> 00:03:13,000
+This is a program for text terminals, for Unix like systems to close it.
+
+48
+00:03:13,000 --> 00:03:16,000
+Just press Kyuki to remember it.
+
+49
+00:03:16,000 --> 00:03:18,000
+Q stands for it.
+
+50
+00:03:18,000 --> 00:03:20,000
+Here, let me press Q.
+
+51
+00:03:21,000 --> 00:03:22,000
+OK, Hillary.
+
+52
+00:03:22,000 --> 00:03:26,000
+So where's the place where you can get check some of the comments that you want to restore?
+
+53
+00:03:26,000 --> 00:03:31,000
+I know that for some students, the way our flag looks like is not very informative.
+
+54
+00:03:32,000 --> 00:03:38,000
+We can't see the detailed content messages we may find on the description of the operation, but not
+
+55
+00:03:38,000 --> 00:03:39,000
+the details about the commit.
+
+56
+00:03:40,000 --> 00:03:47,000
+What would I suggest to you is to use the next command get look with option G here you may find a list
+
+57
+00:03:47,000 --> 00:03:49,000
+of all commits was a red flag reference.
+
+58
+00:03:50,000 --> 00:03:52,000
+Here is our committee that we have lost.
+
+59
+00:03:53,000 --> 00:03:56,000
+Let me create a new branch with the state of that snapshot.
+
+60
+00:03:57,000 --> 00:03:59,000
+Yet Branch lost changes.
+
+61
+00:04:00,000 --> 00:04:08,000
+And now I have to specify, commit checks that I want to restore E 50, be a D great.
+
+62
+00:04:09,000 --> 00:04:13,000
+Now let's check commit history, get log last changes.
+
+63
+00:04:14,000 --> 00:04:19,000
+Just to remind you to check the current history of the specific branch, we should specify branch name
+
+64
+00:04:19,000 --> 00:04:25,000
+next to log command and we can see that our new branch contains commands that were lost.
+
+65
+00:04:26,000 --> 00:04:31,000
+So as far as you may understand, you can restore, Anderson, what was present in any committee in
+
+66
+00:04:31,000 --> 00:04:37,000
+your local repository or anything where hat pointer of your local repository ever pointed to.
+
+67
+00:04:37,000 --> 00:04:40,000
+Also, one more important note.
+
+68
+00:04:40,000 --> 00:04:44,000
+By default, information in red flag is stored for 90 days.
+
+69
+00:04:44,000 --> 00:04:45,000
+Usually it is enough.
+
+70
+00:04:46,000 --> 00:04:52,000
+It is very unlikely that you lived your happy life for 91 days and after that realized that you need
+
+71
+00:04:52,000 --> 00:04:53,000
+to restore some lost command.
+
+72
+00:04:54,000 --> 00:04:57,000
+Let me show you one more Syntex of restoring changes.
+
+73
+00:04:58,000 --> 00:05:03,000
+I'm on the massive branch and I didn't switch to the new branch with the name lost changes that we created
+
+74
+00:05:03,000 --> 00:05:06,000
+with the last comment on the massive branch.
+
+75
+00:05:06,000 --> 00:05:10,000
+I still don't have my last comments after the hard reset.
+
+76
+00:05:11,000 --> 00:05:13,000
+Let me reset was hard to Morcom.
+
+77
+00:05:13,000 --> 00:05:19,000
+It's back here is our leaders had hard to prove that we really moved a few comments back and that we
+
+78
+00:05:19,000 --> 00:05:21,000
+have lost even more comments.
+
+79
+00:05:21,000 --> 00:05:23,000
+Let me show you commit history.
+
+80
+00:05:23,000 --> 00:05:29,000
+You'd log that story and you can see that we lost our five zero beard commit.
+
+81
+00:05:30,000 --> 00:05:34,000
+Let me show you one more time that shows a whole raft.
+
+82
+00:05:34,000 --> 00:05:36,000
+Look, let me show you the flag.
+
+83
+00:05:36,000 --> 00:05:42,000
+Only for the past one hour traffic was option since equals to one our.
+
+84
+00:05:43,000 --> 00:05:48,000
+And I see limited amount of red flag you can use day instead of hours if you wish.
+
+85
+00:05:48,000 --> 00:05:52,000
+So here is a state of our head pointer before I set it.
+
+86
+00:05:52,000 --> 00:05:55,000
+Has Index had at nine and two.
+
+87
+00:05:56,000 --> 00:06:02,000
+That's the sad state of the current branch to the opposition leader, said resorption, hard hat and
+
+88
+00:06:03,000 --> 00:06:04,000
+to unlet.
+
+89
+00:06:04,000 --> 00:06:08,000
+Check our comment history one more time gridlock.
+
+90
+00:06:08,000 --> 00:06:09,000
+And here we are.
+
+91
+00:06:10,000 --> 00:06:13,000
+We successfully restored state of our filesystem and state of our branch.
+
+92
+00:06:13,000 --> 00:06:15,000
+That was before the last reset.
+
+93
+00:06:16,000 --> 00:06:19,000
+I believe this information will help you a lot in the future.
+
+94
+00:06:20,000 --> 00:06:22,000
+That's all what I planned to share with you today.
+
+95
+00:06:22,000 --> 00:06:24,000
+Let's recap what we have learned today.
+
+96
+00:06:25,000 --> 00:06:28,000
+So today we learned what a leader travelogue is.
+
+97
+00:06:28,000 --> 00:06:31,000
+Now you know how to use this command during the lesson.
+
+98
+00:06:31,000 --> 00:06:37,000
+We restore our lost commits by creating a branch from then lost it all by yourself in the current branch
+
+99
+00:06:37,000 --> 00:06:40,000
+to the previous state before some comments were lost.
+
+100
+00:06:40,000 --> 00:06:44,000
+Also, we learned how to show red filtered by time passed.
+
+101
+00:06:45,000 --> 00:06:47,000
+That's all what we have for today.
+
+102
+00:06:47,000 --> 00:06:48,000
+Thanks a lot for your attention.
+
+103
+00:06:49,000 --> 00:06:50,000
+See you in the next lesson.
+

17 - GIT/018 Git cherry-pick moving commits between branches_en.srt

@@ -0,0 +1,592 @@
+1
+00:00:06,000 --> 00:00:10,000
+Hello, Jim, today we're going to discuss with you one more important command that may help you to
+
+2
+00:00:10,000 --> 00:00:13,000
+modify comit history, then we'll talk about cherrypick.
+
+3
+00:00:13,000 --> 00:00:20,000
+Come on, as usual, we'll discuss when we need to use this command after we'll understand when we need
+
+4
+00:00:20,000 --> 00:00:20,000
+to use cherrypick.
+
+5
+00:00:20,000 --> 00:00:25,000
+Command will proceed with our practice exercise to understand how we can use it.
+
+6
+00:00:25,000 --> 00:00:31,000
+In this lesson, I will share with you my experience of using cherrypick and I will tell you why this
+
+7
+00:00:31,000 --> 00:00:33,000
+command is not considered as a best practice.
+
+8
+00:00:33,000 --> 00:00:37,000
+And even despite that, why we may need to use this command some time.
+
+9
+00:00:38,000 --> 00:00:43,000
+I'm going to teach you how to cherrypick multiple commands at once and how to resolve conflicts during
+
+10
+00:00:43,000 --> 00:00:43,000
+cherrypicking.
+
+11
+00:00:44,000 --> 00:00:48,000
+And at the end of the lesson, I will share with you best practices of using cherrypick.
+
+12
+00:00:49,000 --> 00:00:55,000
+So when we have to use cherrypick, there are different cases when you might want to use cherrypick
+
+13
+00:00:55,000 --> 00:00:56,000
+command.
+
+14
+00:00:56,000 --> 00:01:01,000
+Some of them deliver hotfix to the end user as fast as possible.
+
+15
+00:01:02,000 --> 00:01:04,000
+Imagine that you created Reles Branch.
+
+16
+00:01:04,000 --> 00:01:09,000
+Rie's branch should contain only source code that is going to be part of the built of your application
+
+17
+00:01:09,000 --> 00:01:14,000
+that is going to be deployed on your production environment where it will be available to the end user.
+
+18
+00:01:15,000 --> 00:01:20,000
+And imagine that you realize that you're basing on merging of the latest changes before creation of
+
+19
+00:01:20,000 --> 00:01:21,000
+the release branch.
+
+20
+00:01:21,000 --> 00:01:25,000
+You missed important change and now you have a defect in the release branch.
+
+21
+00:01:26,000 --> 00:01:30,000
+The fix for this defect is present in the snapshot in your feature branch.
+
+22
+00:01:31,000 --> 00:01:32,000
+It was tested.
+
+23
+00:01:32,000 --> 00:01:33,000
+It was approved.
+
+24
+00:01:33,000 --> 00:01:39,000
+So the only thing that you have to do is to move the committee from the feature branch to your branch
+
+25
+00:01:39,000 --> 00:01:42,000
+and to move one snapshot from one branch to another.
+
+26
+00:01:42,000 --> 00:01:49,000
+We have to use the feature command or imagine another case and doing changes and restoring lost Kummetz.
+
+27
+00:01:50,000 --> 00:01:56,000
+Not all branches are merged into the master branch and some chametz might be lost using letterer floor
+
+28
+00:01:56,000 --> 00:01:57,000
+command.
+
+29
+00:01:57,000 --> 00:02:01,000
+You may find snapshots that you need and cherrypick it into your branch.
+
+30
+00:02:01,000 --> 00:02:08,000
+One more scenario, regular time collaboration in case you and team members work on the same feature
+
+31
+00:02:08,000 --> 00:02:13,000
+and you have some shared functionality, you might want to test something on your branch that includes
+
+32
+00:02:13,000 --> 00:02:14,000
+other changes.
+
+33
+00:02:14,000 --> 00:02:21,000
+For example, backend engineers created a data structure that Fronton team also needs to use, and Fronton
+
+34
+00:02:21,000 --> 00:02:26,000
+developers may use cherrypick command to get those changes into their branch.
+
+35
+00:02:26,000 --> 00:02:31,000
+Probably during the life of the developer, you will find other real life cases when you may use to
+
+36
+00:02:31,000 --> 00:02:36,000
+be command, but I believe you understand why you may want to use it.
+
+37
+00:02:36,000 --> 00:02:38,000
+And now attention.
+
+38
+00:02:38,000 --> 00:02:41,000
+I don't want you to share with attack tactless information.
+
+39
+00:02:41,000 --> 00:02:44,000
+That and reporter had told you that using of cherrypick is a best practice.
+
+40
+00:02:45,000 --> 00:02:51,000
+I want to say that cherrypick command usually consider is not a good practice and regular mergers are
+
+41
+00:02:51,000 --> 00:02:53,000
+preferred instead when it is possible.
+
+42
+00:02:54,000 --> 00:03:01,000
+But sometimes you might want to use this command while you Topeka's consider it is not a best practice
+
+43
+00:03:01,000 --> 00:03:02,000
+notice.
+
+44
+00:03:02,000 --> 00:03:08,000
+I said literally consider it not as a best practice, but not necessarily the bad thing.
+
+45
+00:03:09,000 --> 00:03:12,000
+To understand this, let's review how Get-Rich-Quick works.
+
+46
+00:03:12,000 --> 00:03:15,000
+It creates a tension separate come.
+
+47
+00:03:15,000 --> 00:03:20,000
+It was different hash and has no reference to original comment.
+
+48
+00:03:21,000 --> 00:03:27,000
+Content of command will be fully duplicated, but it will consider Newcome it an original one as two
+
+49
+00:03:27,000 --> 00:03:28,000
+different commands.
+
+50
+00:03:28,000 --> 00:03:34,000
+That's why some developers may consider cherrypick as a bad thing because it may cause problems like
+
+51
+00:03:34,000 --> 00:03:38,000
+having duplicate commands and multiple branches messing up with a good history and others.
+
+52
+00:03:39,000 --> 00:03:43,000
+But in case you are using this command attentively, there is no harm in that.
+
+53
+00:03:44,000 --> 00:03:50,000
+For example, there might be cases when you can't merge some branch because it contains a lot of other
+
+54
+00:03:50,000 --> 00:03:52,000
+changes that are not needed anymore.
+
+55
+00:03:52,000 --> 00:03:56,000
+And at some specific moment of time, you need only one single command.
+
+56
+00:03:56,000 --> 00:04:02,000
+That's where cherrypick command may help you so used cherrypick with caution.
+
+57
+00:04:02,000 --> 00:04:07,000
+At the end of the lesson, we are going to summarize rules that you have to follow during the cherrypicking.
+
+58
+00:04:08,000 --> 00:04:14,000
+Now let me show you the real example of cherrypicking the head for this lesson for the sake of the Dharma
+
+59
+00:04:14,000 --> 00:04:16,000
+Abbotabad branch was fuken its.
+
+60
+00:04:16,000 --> 00:04:21,000
+Let me briefly explain to you the state of my current repository so that you would understand the example.
+
+61
+00:04:22,000 --> 00:04:27,000
+Imagine that I am working on the implementation of LOG-IN functionality and I create a separate branch
+
+62
+00:04:27,000 --> 00:04:30,000
+for that was the name Keet three zero eight log.
+
+63
+00:04:30,000 --> 00:04:33,000
+Again, you can see that I am currently on it.
+
+64
+00:04:34,000 --> 00:04:37,000
+Let me show you the history of what I have already done.
+
+65
+00:04:38,000 --> 00:04:41,000
+This log was option one line necessary.
+
+66
+00:04:41,000 --> 00:04:46,000
+Option one line allows me to format output in a bit different ways than usual.
+
+67
+00:04:46,000 --> 00:04:51,000
+I press enter here what I have already done while being on this branch.
+
+68
+00:04:52,000 --> 00:04:54,000
+I implement in styles for login bottom.
+
+69
+00:04:54,000 --> 00:04:58,000
+Also I implement and backend part of login feature.
+
+70
+00:04:58,000 --> 00:05:01,000
+And here's a snapshot of the original master branch.
+
+71
+00:05:01,000 --> 00:05:03,000
+And imagine that during the.
+
+72
+00:05:03,000 --> 00:05:09,000
+Essence of my work quality assurance engineers found a lot of defects, and we are not in the position
+
+73
+00:05:09,000 --> 00:05:16,000
+to match my branch to a three zero eight into the master branch, but everybody really liked the style
+
+74
+00:05:16,000 --> 00:05:21,000
+of my login button and product on requested to have the other buttons in the same style.
+
+75
+00:05:22,000 --> 00:05:28,000
+That's why I want to prepare pool requests for only styles of my button and we'll merge that branch
+
+76
+00:05:28,000 --> 00:05:33,000
+into the master so that other developers also will be able to pick up the changes.
+
+77
+00:05:33,000 --> 00:05:36,000
+While I will be fixing all the defects.
+
+78
+00:05:36,000 --> 00:05:38,000
+Was back in court for the next week or two.
+
+79
+00:05:39,000 --> 00:05:41,000
+Just joking, you know that I would fix it faster.
+
+80
+00:05:42,000 --> 00:05:48,000
+But just as an example, this shouldn't be a problem because I will rebase my branch with the back and
+
+81
+00:05:48,000 --> 00:05:55,000
+quote on the master before merging or even just remove Starlin snapshot from the current branch to understand
+
+82
+00:05:55,000 --> 00:05:56,000
+the real life case.
+
+83
+00:05:57,000 --> 00:05:59,000
+Let me now show you how to do that.
+
+84
+00:05:59,000 --> 00:06:03,000
+First of all, let me create the branch from the latest master branch.
+
+85
+00:06:04,000 --> 00:06:05,000
+Good switch, master.
+
+86
+00:06:06,000 --> 00:06:10,000
+Nudes, which resorption CGA three zero nine modern styles.
+
+87
+00:06:12,000 --> 00:06:19,000
+OK, I'm on the new branch and imagine that I did some changes in the log into this House file, just
+
+88
+00:06:19,000 --> 00:06:25,000
+did any random changes, Nonno style slash log in order to assess.
+
+89
+00:06:25,000 --> 00:06:29,000
+Let me write here some text, some changes.
+
+90
+00:06:30,000 --> 00:06:37,000
+And save it now, let me come in this year to commit with option A and resorption and subcamp.
+
+91
+00:06:39,000 --> 00:06:47,000
+Hypocenter and now being on this branch, I have to cherry pick this game, it was Jackson E, C, six,
+
+92
+00:06:47,000 --> 00:06:52,000
+B, five, E, C, two copies that come in and apply it on my new branch.
+
+93
+00:06:52,000 --> 00:06:54,000
+Let me execute the next command.
+
+94
+00:06:55,000 --> 00:06:57,000
+Get cherrypick E, C six.
+
+95
+00:06:57,000 --> 00:06:58,000
+B, five.
+
+96
+00:06:58,000 --> 00:06:59,000
+E, c.
+
+97
+00:07:00,000 --> 00:07:06,000
+In case we wouldn't adjust the says as file, we want to see conflicts here and your it would be applied,
+
+98
+00:07:07,000 --> 00:07:09,000
+but that is way too easy for you.
+
+99
+00:07:10,000 --> 00:07:16,000
+I wanted to imitate state of the conflict during the cherrypicking to show you the process of the conflict
+
+100
+00:07:16,000 --> 00:07:17,000
+resolving during the cherrypick.
+
+101
+00:07:18,000 --> 00:07:24,000
+You see that it indicates that we are in the process of the cherry picking and gives us advice to resolve
+
+102
+00:07:24,000 --> 00:07:26,000
+conflicts and add files to the staging area.
+
+103
+00:07:27,000 --> 00:07:28,000
+Let me check your status.
+
+104
+00:07:29,000 --> 00:07:37,000
+And see here in the but it is said that there is a conflict in Logan says file, so let's open it in
+
+105
+00:07:37,000 --> 00:07:40,000
+the editor and let's resolve the conflicts now.
+
+106
+00:07:41,000 --> 00:07:47,000
+No styles log into SS will imitate the fact that we resolved all conflicts.
+
+107
+00:07:49,000 --> 00:07:53,000
+Now, let's mark this file as a result, get at DOT.
+
+108
+00:07:53,000 --> 00:08:01,000
+Now, let's continue our cherry picking process to do this, let's perform the next command, get cherrypick
+
+109
+00:08:01,000 --> 00:08:07,000
+with option continue and it allows us to adjust, commit message by default.
+
+110
+00:08:07,000 --> 00:08:10,000
+It keeps the region commit message of the previous commit.
+
+111
+00:08:11,000 --> 00:08:16,000
+Let's save and close this file and we can see that we applied our changes here.
+
+112
+00:08:16,000 --> 00:08:18,000
+Let's check our current history.
+
+113
+00:08:19,000 --> 00:08:21,000
+Good luck with option one line.
+
+114
+00:08:21,000 --> 00:08:22,000
+That's three.
+
+115
+00:08:23,000 --> 00:08:28,000
+And here's our new comment and attention, in case you would compare, check some of this comet and
+
+116
+00:08:28,000 --> 00:08:34,000
+check some of original comet from a three zero eight range, you're going to find that they are different.
+
+117
+00:08:35,000 --> 00:08:38,000
+That means that these two are not the same comet.
+
+118
+00:08:39,000 --> 00:08:42,000
+This one is just a copy of the first one.
+
+119
+00:08:42,000 --> 00:08:49,000
+And now a few more important variations and options of cherrypick command in case something went wrong
+
+120
+00:08:49,000 --> 00:08:50,000
+during the conflict resolution.
+
+121
+00:08:50,000 --> 00:08:56,000
+You can just abort the process of cherrypicking like this, get cherrypick with option abort.
+
+122
+00:08:57,000 --> 00:09:01,000
+Also, if you wish, you may cherry pick multiple comets at once.
+
+123
+00:09:01,000 --> 00:09:02,000
+To do this.
+
+124
+00:09:02,000 --> 00:09:08,000
+You have specified checksum of all comets separated by space like this year.
+
+125
+00:09:08,000 --> 00:09:15,000
+Cherrypick E, C six B five e C and three F three one six six six.
+
+126
+00:09:16,000 --> 00:09:17,000
+Those are two comets from our damos.
+
+127
+00:09:18,000 --> 00:09:22,000
+Now when you know how to use cherrypick, let's talk about the best practices.
+
+128
+00:09:24,000 --> 00:09:30,000
+The rule number one, if it's not critical and you can apply necessary changes with much opt for much
+
+129
+00:09:30,000 --> 00:09:37,000
+option, it is considered to be a general practice to prefer much option of a cherrypick rule number
+
+130
+00:09:37,000 --> 00:09:44,000
+to avoid creating any duplication by using cherrypick if you cherry picked commands and removed all
+
+131
+00:09:44,000 --> 00:09:46,000
+branch or just reset the old branch.
+
+132
+00:09:46,000 --> 00:09:47,000
+That's fine.
+
+133
+00:09:47,000 --> 00:09:49,000
+And this will not lead to any issues.
+
+134
+00:09:50,000 --> 00:09:54,000
+Potential issues may happen in case you keep two branches and have duplicated Kummetz.
+
+135
+00:09:55,000 --> 00:10:01,000
+Rule number three, sometimes it is considered as a good practice during the cherrypick to specify the
+
+136
+00:10:01,000 --> 00:10:07,000
+hash code or the original commit, it may help you to do this in case you will use exception like this.
+
+137
+00:10:07,000 --> 00:10:10,000
+Get your pick was option X.
+
+138
+00:10:10,000 --> 00:10:16,000
+This option will automatically adds information about the regional committee into your new one.
+
+139
+00:10:16,000 --> 00:10:20,000
+And here on the screenshot, you may see how your comit message will look like.
+
+140
+00:10:21,000 --> 00:10:26,000
+You learned a lot today about cherrypick, let's recap what we have learned today.
+
+141
+00:10:27,000 --> 00:10:32,000
+Now, you know when you might need to apply cherrypick command, because we discussed with you different
+
+142
+00:10:32,000 --> 00:10:34,000
+cases when this command will help you.
+
+143
+00:10:35,000 --> 00:10:39,000
+Also, you understood why cherrypick is not considered to be as a good practice.
+
+144
+00:10:39,000 --> 00:10:43,000
+One real example, you saw how to resolve conflicts during cherrypicking.
+
+145
+00:10:44,000 --> 00:10:47,000
+Now you know how to cherrypick multiple Kummetz at once.
+
+146
+00:10:47,000 --> 00:10:52,000
+And at the end of the lesson, we learned best practices of using cherrypick command.
+
+147
+00:10:52,000 --> 00:10:54,000
+That's all for today.
+
+148
+00:10:54,000 --> 00:10:57,000
+Thanks a lot for your attention and see you in the next lesson.
+

17 - GIT/019 Cloning remote repository git clone.html

@@ -0,0 +1,69 @@
+<!DOCTYPE html>
+<html lang="en">
+    <head>
+        <meta charset="UTF-8" />
+        <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+        <title>Cloning remote repository git clone</title>
+
+        <style>
+            * {
+                box-sizing: border-box;
+                margin: 0;
+                padding: 0;
+            }
+            body {
+                font-family: var(--font-stack-text);
+                font-weight: 400;
+                line-height: 1.4;
+                font-size: 1.6rem;
+                color: #2d2f31;
+            }
+            .container {
+                position: relative;
+                height: 100%;
+                overflow-y: auto;
+            }
+            .content {
+                padding: 3.2rem 4.8rem;
+                word-break: break-word;
+                max-width: 69.6rem;
+                margin: 0 auto;
+            }
+            .heading {
+                margin-bottom: 24px;
+                font-family: -apple-system, BlinkMacSystemFont, Roboto, "Segoe UI", Helvetica, Arial, sans-serif,
+                    "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
+                font-weight: 700;
+                line-height: 1.2;
+                letter-spacing: 0;
+                font-size: 32px;
+                max-width: 36em;
+            }
+            .article-asset-container {
+                padding: 2.4rem;
+            }
+            .article-asset-container p {
+                font-size: 19px;
+            }
+            code {
+                background-color: #fff;
+                border: 1px solid #d1d7dc;
+                color: #b4690e;
+                font-size: 80%;
+                padding: 0.2rem 0.4rem;
+                font-family: sfmono-regular, Consolas, liberation mono, Menlo, Courier, monospace;
+            }
+            p {
+                font-weight: 400;
+            }
+        </style>
+    </head>
+    <body>
+        <div class="container">
+            <div class="content">
+                <div class="heading">Cloning remote repository git clone</div>
+                <div class="article-asset-container"><p>To clone remote repository, please, follow next steps:</p><p>- Open the repository that you want to clone, for example, open my repository for my Java students here - https://github.com/AndriiPiatakha/learnit_java_core</p><p>- On the github, find green button with the 'Code' text on it. <br>- Select the protocol that you want to use during the cloning git repository. You can select either HTTPS or SSH. Please, take a look at the screenshot.<br></p><figure><img src="https://img-c.udemycdn.com/redactor/raw/article_lecture/2020-11-05_14-12-12-67371fa192aa3ddf03456864b51b9a53.jpg"></figure><p><br>- copy the string with address to the clipboard. </p><p>- navigate in your filesystem where you want to clone your repository<br>- open gitbash in that directory and type the next:<br><br><strong><em>git clone &lt;HERE&nbsp;PASTE&nbsp;THE&nbsp;STATE&nbsp;OF&nbsp;YOUR&nbsp;CLIPBOARD&gt;</em></strong></p><p>Take a look at the screenshot:</p><figure><img src="https://img-c.udemycdn.com/redactor/raw/article_lecture/2020-11-05_14-14-43-dd660c5627f6c2b83a7fdd847108c5e1.jpg"></figure><p>- Press enter button</p><p>- Congratulations! You have just cloned the remote repository!</p></div>
+            </div>
+        </div>
+    </body>
+</html>

17 - GIT/020 Git and Eclipse integration_en.srt

@@ -0,0 +1,832 @@
+1
+00:00:06,000 --> 00:00:10,000
+And now the students in this class and we are going to discuss the topic that will be interesting for
+
+2
+00:00:10,000 --> 00:00:16,000
+developers who work in such integrated development environment as Eclipse, we're going to learn today
+
+3
+00:00:16,000 --> 00:00:22,000
+how to integrate it with eclipse for development come for besides buttons and widgets that will configure
+
+4
+00:00:22,000 --> 00:00:24,000
+an eclipse during the lesson.
+
+5
+00:00:24,000 --> 00:00:30,000
+I will show you how you can use get Bush directly from the eclipse together on real example.
+
+6
+00:00:30,000 --> 00:00:33,000
+We are going to learn how to execute basic operations from Eclipse.
+
+7
+00:00:34,000 --> 00:00:40,000
+I make overview of widgets that will allow you to see good history navigate between branches, push
+
+8
+00:00:40,000 --> 00:00:43,000
+and pull changes from the remote repository.
+
+9
+00:00:43,000 --> 00:00:48,000
+After this lesson, you will learn how you can resolve conflicts in eclipse interface.
+
+10
+00:00:49,000 --> 00:00:51,000
+Let's start and turn the topic.
+
+11
+00:00:51,000 --> 00:00:53,000
+I said just jump into the practice.
+
+12
+00:00:53,000 --> 00:00:55,000
+Here's my Eclipse workspace.
+
+13
+00:00:55,000 --> 00:01:00,000
+I created a completely new workspace and reset perspective for you to default to configure it with you
+
+14
+00:01:00,000 --> 00:01:01,000
+from scratch.
+
+15
+00:01:01,000 --> 00:01:07,000
+I have Empathies Java Project, which we did together during the learning of the get in the workspace.
+
+16
+00:01:07,000 --> 00:01:09,000
+How to Impact Projects into Eclipse.
+
+17
+00:01:09,000 --> 00:01:11,000
+I'm going to show you in the separate lesson.
+
+18
+00:01:11,000 --> 00:01:14,000
+Do not lose focus from the topic right now.
+
+19
+00:01:15,000 --> 00:01:22,000
+When I in the Project Eclipse automatically recognised that there is a git repository and you see that
+
+20
+00:01:22,000 --> 00:01:25,000
+in square brackets, it is even specifying my current branch.
+
+21
+00:01:26,000 --> 00:01:31,000
+But nevertheless, I will show you how that you get repository to eclipse manually just in case.
+
+22
+00:01:32,000 --> 00:01:35,000
+First of all, let's add all views here that we need.
+
+23
+00:01:36,000 --> 00:01:38,000
+Click on Window Show.
+
+24
+00:01:38,000 --> 00:01:43,000
+You are the one here git folder or use search bar to find it faster.
+
+25
+00:01:44,000 --> 00:01:47,000
+I would say that you'd stadion and git repositories.
+
+26
+00:01:47,000 --> 00:01:48,000
+Those are tools that you need.
+
+27
+00:01:48,000 --> 00:01:49,000
+One hundred percent.
+
+28
+00:01:50,000 --> 00:01:56,000
+Well, at least in my opinion, I'm holding control button and with a mouse left click select the options
+
+29
+00:01:56,000 --> 00:01:57,000
+that I need.
+
+30
+00:01:58,000 --> 00:02:04,000
+Let's also select get lock and it is good that we have learned how to work with Gatins again.
+
+31
+00:02:04,000 --> 00:02:08,000
+But at least now you already understand what all these views are about.
+
+32
+00:02:09,000 --> 00:02:13,000
+You already know what is a staging area, what is a good red flag.
+
+33
+00:02:13,000 --> 00:02:19,000
+You already know what they're getting directed for basis after we selected all use we need.
+
+34
+00:02:19,000 --> 00:02:20,000
+Let's press open button.
+
+35
+00:02:22,000 --> 00:02:30,000
+Nice views were opened just to remind you that you can move these views wherever you like them most
+
+36
+00:02:30,000 --> 00:02:32,000
+here in the clips, for example.
+
+37
+00:02:32,000 --> 00:02:36,000
+Let me move git repositories widget here at the bottom with other views.
+
+38
+00:02:36,000 --> 00:02:41,000
+And you can see that my clips recognized each repository in my project automatically.
+
+39
+00:02:42,000 --> 00:02:47,000
+But just for the future and just in case, I want you to know how to add the existing repository to
+
+40
+00:02:47,000 --> 00:02:53,000
+their clips, because it might be that the clips will not automatically recognize that you have not
+
+41
+00:02:53,000 --> 00:02:54,000
+get folder in your project.
+
+42
+00:02:54,000 --> 00:02:57,000
+And in this case you have to edit manually.
+
+43
+00:02:58,000 --> 00:03:03,000
+For the sake of example, let me remove the digital repository from this view in the clips mouse right.
+
+44
+00:03:03,000 --> 00:03:11,000
+Click remove repository from you because I want to remove git repository only from eclipse view and
+
+45
+00:03:11,000 --> 00:03:17,000
+I don't want to remove the don't get folder from the file system and I don't want to remove the project
+
+46
+00:03:17,000 --> 00:03:20,000
+and eclipse associated with this git repository.
+
+47
+00:03:20,000 --> 00:03:23,000
+I want to keep project in my workspace for you.
+
+48
+00:03:23,000 --> 00:03:25,000
+That's why I press this button.
+
+49
+00:03:26,000 --> 00:03:27,000
+Awesome.
+
+50
+00:03:27,000 --> 00:03:30,000
+Now we don't have any repository here.
+
+51
+00:03:30,000 --> 00:03:32,000
+You can create a new repository if you wish.
+
+52
+00:03:33,000 --> 00:03:35,000
+That is similar to executing Mutiny's.
+
+53
+00:03:35,000 --> 00:03:35,000
+Come on.
+
+54
+00:03:36,000 --> 00:03:40,000
+You might also an existing repository with the help of the eclipse wizard.
+
+55
+00:03:40,000 --> 00:03:45,000
+And in case you already have git repository in your computer, you can just add it to the workspace.
+
+56
+00:03:46,000 --> 00:03:51,000
+I believe there is no need to go over each of this option in detail because creating a good repository
+
+57
+00:03:51,000 --> 00:03:56,000
+is just specifying directory where you want to create don't get older and present.
+
+58
+00:03:56,000 --> 00:04:02,000
+Great Bottom Clonan Repository is just specifying the past as a repository and your credentials in case
+
+59
+00:04:02,000 --> 00:04:05,000
+you want a repository with the help of a HTTPS protocol.
+
+60
+00:04:06,000 --> 00:04:13,000
+But from my experience, this option at an existing local repository is used most of the times by me,
+
+61
+00:04:14,000 --> 00:04:19,000
+and I don't know why, probably because I don't rely on the eclipse tools to manage Mangat repository.
+
+62
+00:04:19,000 --> 00:04:26,000
+Usually I fetch all projects with a simple git clone command in the git bash and after that an important
+
+63
+00:04:26,000 --> 00:04:30,000
+project to the eclipse and an existing local git repository.
+
+64
+00:04:31,000 --> 00:04:37,000
+Personally, for me, this option is the easiest one, but my job is to share with you all possible
+
+65
+00:04:37,000 --> 00:04:40,000
+options and let you decide what works the best for you.
+
+66
+00:04:41,000 --> 00:04:46,000
+That's why let me show you how I usually add existing local repositories to Eclipse.
+
+67
+00:04:46,000 --> 00:04:53,000
+And now you should specify a folder where your local repository is located and navigate it to the folder
+
+68
+00:04:53,000 --> 00:04:59,000
+that we created together during the course while learning Gaede and press select folder button here
+
+69
+00:04:59,000 --> 00:05:02,000
+clip's shows me repositories that it found in this folder.
+
+70
+00:05:02,000 --> 00:05:08,000
+I checked this checkbox and press that button and here's my repository back again.
+
+71
+00:05:09,000 --> 00:05:10,000
+Let me expand it.
+
+72
+00:05:11,000 --> 00:05:13,000
+It is very convenient to switch branches here.
+
+73
+00:05:14,000 --> 00:05:20,000
+You might find here local and remote branches nable left click on the massive branch will move me to
+
+74
+00:05:20,000 --> 00:05:23,000
+the master branch eclipse will ask for confirmation.
+
+75
+00:05:24,000 --> 00:05:28,000
+Just click checkout and you already know how you check out command works.
+
+76
+00:05:28,000 --> 00:05:35,000
+So I believe you understood what happened behind the scene and you may see a small T care next to the
+
+77
+00:05:35,000 --> 00:05:36,000
+massive branch name.
+
+78
+00:05:37,000 --> 00:05:40,000
+Let me switch back to the Kayseri 09 branch.
+
+79
+00:05:41,000 --> 00:05:41,000
+Right.
+
+80
+00:05:41,000 --> 00:05:47,000
+Click on the branch would allow you to do the operations that will want to perform in Git Bush.
+
+81
+00:05:47,000 --> 00:05:51,000
+You may reset branch in different modes, so it makes and hard.
+
+82
+00:05:52,000 --> 00:05:58,000
+You may replace your branch if needed, merged, delete, rename and perform all other operations that
+
+83
+00:05:58,000 --> 00:06:00,000
+you may perform in the git bash.
+
+84
+00:06:01,000 --> 00:06:05,000
+We don't have docs in our repository yet, so it is empty here.
+
+85
+00:06:06,000 --> 00:06:13,000
+What a task is will be discussed in the separate question here, you may find your main references in
+
+86
+00:06:13,000 --> 00:06:13,000
+your repository.
+
+87
+00:06:13,000 --> 00:06:17,000
+You may check out the if you wish in remote.
+
+88
+00:06:17,000 --> 00:06:24,000
+You may check to what remote repository you are connected right now in Stasch comments, you can explore
+
+89
+00:06:24,000 --> 00:06:25,000
+the state of your stasch.
+
+90
+00:06:26,000 --> 00:06:33,000
+And you're working directory, that is technically a project that may collapse everything here, based
+
+91
+00:06:33,000 --> 00:06:38,000
+on my experience, I mostly use this section to navigate between branches, create new branch if needed,
+
+92
+00:06:38,000 --> 00:06:40,000
+and remove all branches.
+
+93
+00:06:41,000 --> 00:06:48,000
+Let's move on this, Sunny, as a positive name means that I have some onstage changes you may find
+
+94
+00:06:48,000 --> 00:06:48,000
+similar.
+
+95
+00:06:48,000 --> 00:06:54,000
+Some here in the package explore how to identify what change are we talking about?
+
+96
+00:06:54,000 --> 00:06:56,000
+Let's check separate tab for that.
+
+97
+00:06:56,000 --> 00:07:02,000
+Yet, Stadion here, you can manage what is in the staging area right here, commit message and commit
+
+98
+00:07:02,000 --> 00:07:03,000
+changes if you want.
+
+99
+00:07:03,000 --> 00:07:08,000
+You also can commit and push to the remote with a single button click here.
+
+100
+00:07:08,000 --> 00:07:13,000
+From this view, I see that DOT project file is marked as unstaged changes here.
+
+101
+00:07:14,000 --> 00:07:20,000
+This is configuration of eclipse file that the groups created after we implement the project into it.
+
+102
+00:07:20,000 --> 00:07:22,000
+Let me update yet.
+
+103
+00:07:22,000 --> 00:07:23,000
+Ignore the just ignore this file.
+
+104
+00:07:24,000 --> 00:07:28,000
+I can't find it in your file in the package Explorer review.
+
+105
+00:07:28,000 --> 00:07:30,000
+But let me open the gate of you for that.
+
+106
+00:07:31,000 --> 00:07:34,000
+I click window shoe view navigator.
+
+107
+00:07:35,000 --> 00:07:42,000
+And this view, I can see old files as they are look like in my file system and here's Technophile,
+
+108
+00:07:43,000 --> 00:07:46,000
+let me add here DOT Project and save the file.
+
+109
+00:07:47,000 --> 00:07:53,000
+And you must use it instantly, not project file is gone from unstaged changes and to ignore it, you're
+
+110
+00:07:54,000 --> 00:07:59,000
+going to press this green plus sign to add all files from this section to the stage changes section.
+
+111
+00:07:59,000 --> 00:08:00,000
+That's right.
+
+112
+00:08:00,000 --> 00:08:03,000
+Commit message and troops files ignored.
+
+113
+00:08:03,000 --> 00:08:09,000
+And I can make a comment by clicking here, but probably I would commit and push changes to the remote
+
+114
+00:08:09,000 --> 00:08:11,000
+repository simultaneously.
+
+115
+00:08:11,000 --> 00:08:16,000
+To do this, I have to click on it and push button here in the desert.
+
+116
+00:08:16,000 --> 00:08:19,000
+You should set up stream branch for the current branch.
+
+117
+00:08:19,000 --> 00:08:25,000
+That is exactly what we did when we specified you option during the push to the remote repository.
+
+118
+00:08:26,000 --> 00:08:32,000
+Just click all these buttons until you see confirmation that your changes were pushed because the remote
+
+119
+00:08:32,000 --> 00:08:37,000
+we may check GitHub, but believe me, changes are there in the remote already.
+
+120
+00:08:37,000 --> 00:08:40,000
+Let me show you a few more things you can press.
+
+121
+00:08:40,000 --> 00:08:41,000
+Mouse, right.
+
+122
+00:08:41,000 --> 00:08:44,000
+Click on the project and you'll find a team section.
+
+123
+00:08:45,000 --> 00:08:48,000
+This section is integration with it in Eclipse.
+
+124
+00:08:48,000 --> 00:08:54,000
+And you might find here a lot of different options like fetch from upstream push or bold changes and
+
+125
+00:08:54,000 --> 00:08:55,000
+many others.
+
+126
+00:08:56,000 --> 00:09:02,000
+Take your time to investigate the section and ask me in case you have any questions to check, commit
+
+127
+00:09:02,000 --> 00:09:02,000
+history.
+
+128
+00:09:03,000 --> 00:09:06,000
+You can press show in history here.
+
+129
+00:09:06,000 --> 00:09:11,000
+You may see cammed hash commit message, author of the Commit and Date of the Snapshot.
+
+130
+00:09:11,000 --> 00:09:16,000
+And this window, you can check what files were changed in scope of the particular comment.
+
+131
+00:09:16,000 --> 00:09:21,000
+You may open the file to see the difference before and after the snapshot to understand what exactly
+
+132
+00:09:21,000 --> 00:09:22,000
+was changed.
+
+133
+00:09:23,000 --> 00:09:28,000
+This is where we use a full tool during the investigation of the effects when after specific commit
+
+134
+00:09:28,000 --> 00:09:29,000
+something went wrong.
+
+135
+00:09:30,000 --> 00:09:35,000
+Also here in the history, you may reset your branch to a specific committee or check out there.
+
+136
+00:09:36,000 --> 00:09:37,000
+You just click mouse, right.
+
+137
+00:09:37,000 --> 00:09:40,000
+Click and select exactly what you need.
+
+138
+00:09:41,000 --> 00:09:46,000
+Now I want to show you a few more configurations that I found extremely helpful.
+
+139
+00:09:46,000 --> 00:09:50,000
+I want to tell you how you can add a few buttons here on the toolbar.
+
+140
+00:09:50,000 --> 00:09:54,000
+Click window perspective, customize perspective.
+
+141
+00:09:55,000 --> 00:09:59,000
+Now go to the action of ability and select it here.
+
+142
+00:09:59,000 --> 00:10:05,000
+After that, go to the toolbar visibility and make sure that it is selected here.
+
+143
+00:10:06,000 --> 00:10:11,000
+Click, apply and close, and now here on the top, you have very convenient buttons.
+
+144
+00:10:12,000 --> 00:10:20,000
+No matter what you want to do, push back from upstream pool, check out the branch, Rebase Mirch,
+
+145
+00:10:20,000 --> 00:10:26,000
+or he said you can start the separation's simply by clicking the right button in the toolbar.
+
+146
+00:10:27,000 --> 00:10:33,000
+And even in case you can't find is important that you need or you want to execute some specific command
+
+147
+00:10:33,000 --> 00:10:34,000
+was a specific option.
+
+148
+00:10:34,000 --> 00:10:40,000
+You always may open it feedback directly from Eclipse and start working it to open it.
+
+149
+00:10:40,000 --> 00:10:44,000
+Bushing An Eclipse finds the icon of the console in the toolbar.
+
+150
+00:10:45,000 --> 00:10:48,000
+Hear this, click on it and select it.
+
+151
+00:10:48,000 --> 00:10:53,000
+Bush in the dropdown here in the bus should be installed on your computer.
+
+152
+00:10:53,000 --> 00:10:58,000
+In either case, you won't be able to find it here in the dropdown list.
+
+153
+00:10:58,000 --> 00:11:02,000
+Now you may click OK Button and terminal is opened.
+
+154
+00:11:03,000 --> 00:11:05,000
+Important thing to mention here.
+
+155
+00:11:05,000 --> 00:11:11,000
+Always pay attention to the directory WAGGETT Bush is opened in case you have multiple yet repositories
+
+156
+00:11:11,000 --> 00:11:19,000
+in the single eclipse workspace that keeps my open you another directory or it may open your home directory
+
+157
+00:11:20,000 --> 00:11:23,000
+to make sure that eclipse will open the user right directly.
+
+158
+00:11:23,000 --> 00:11:29,000
+I always press the project first here and only after that I click open terminal icon homes.
+
+159
+00:11:29,000 --> 00:11:31,000
+This information will help you.
+
+160
+00:11:31,000 --> 00:11:33,000
+That is practical, deep.
+
+161
+00:11:33,000 --> 00:11:35,000
+That is really helpful to students in my opinion.
+
+162
+00:11:36,000 --> 00:11:38,000
+We didn't talk about Rafalski yet.
+
+163
+00:11:38,000 --> 00:11:40,000
+Nothing special here.
+
+164
+00:11:40,000 --> 00:11:44,000
+I believe you already learned in the separate lesson what a greater focus here.
+
+165
+00:11:44,000 --> 00:11:48,000
+You might find the red flag, if you will domus right click.
+
+166
+00:11:48,000 --> 00:11:51,000
+You can find additional options that might be useful for you.
+
+167
+00:11:52,000 --> 00:11:57,000
+And the last things that I wanted to share with you today is to show you how you can resolve conflicts
+
+168
+00:11:57,000 --> 00:12:02,000
+in eclipse, especially for that I prepared a separate branch where I reproduce, merge conflicts,
+
+169
+00:12:02,000 --> 00:12:06,000
+state how to reproduce and what merge conflict is.
+
+170
+00:12:06,000 --> 00:12:12,000
+Please feel free to learn in the separate lesson dedicated to the merge conflicts in this lesson output
+
+171
+00:12:12,000 --> 00:12:15,000
+the stress only on the eclipse tools to integrate with the grid.
+
+172
+00:12:16,000 --> 00:12:19,000
+Here is a separate branch with so much conflict in it.
+
+173
+00:12:20,000 --> 00:12:22,000
+I called the branch merge conflict dilemma.
+
+174
+00:12:23,000 --> 00:12:29,000
+Usually when you have much conflict, eclipse highlights to your files in which you have much conflict
+
+175
+00:12:29,000 --> 00:12:30,000
+with the red dots like this.
+
+176
+00:12:31,000 --> 00:12:37,000
+So now it is impossible to mis file with the next conflict when we open the file, which is a good science
+
+177
+00:12:37,000 --> 00:12:41,000
+where I get separated for different state of the file from different snapshots.
+
+178
+00:12:42,000 --> 00:12:45,000
+But the groups offer special tool to merge conflicts in files.
+
+179
+00:12:46,000 --> 00:12:48,000
+Let me show it to you, Mouse.
+
+180
+00:12:48,000 --> 00:12:53,000
+Right, click on file game merge two here on top.
+
+181
+00:12:53,000 --> 00:12:56,000
+You are going to see Kummetz hash that have conflict.
+
+182
+00:12:57,000 --> 00:13:04,000
+Usually you can't edit text in the window on the right, but you can modify text in the window on the
+
+183
+00:13:04,000 --> 00:13:04,000
+left.
+
+184
+00:13:04,000 --> 00:13:09,000
+Here you can click this arrow to place everything from the right window to the left window.
+
+185
+00:13:10,000 --> 00:13:15,000
+When you are going to have more conflicts, there will be different arrows for each specific conflict.
+
+186
+00:13:16,000 --> 00:13:21,000
+And after you modify the file on the left, you can press control and ask to save the file.
+
+187
+00:13:21,000 --> 00:13:27,000
+If we would check the same file in the text editor, we are going to find that all signs that it put
+
+188
+00:13:27,000 --> 00:13:27,000
+here.
+
+189
+00:13:27,000 --> 00:13:31,000
+I removed grate in the gas station.
+
+190
+00:13:31,000 --> 00:13:34,000
+You can put a file to the staging area to more conflict.
+
+191
+00:13:34,000 --> 00:13:39,000
+As a result, when conflict is resolved, you may see a small asterisk on the file.
+
+192
+00:13:39,000 --> 00:13:45,000
+And after all, conflicts are resolved and there are no more red dots, you can open it.
+
+193
+00:13:45,000 --> 00:13:46,000
+Brush and continue.
+
+194
+00:13:46,000 --> 00:13:48,000
+Is a rebasing or cherrypicking something?
+
+195
+00:13:48,000 --> 00:13:50,000
+What caused the merge conflicts?
+
+196
+00:13:51,000 --> 00:13:55,000
+I believe we learned a lot today about the clips and get integration.
+
+197
+00:13:55,000 --> 00:14:02,000
+Now I want you to take your time and as much heat related violence as possible to learn the material
+
+198
+00:14:02,000 --> 00:14:02,000
+better.
+
+199
+00:14:02,000 --> 00:14:06,000
+The best thing to learn this is to practice as much as you can.
+
+200
+00:14:07,000 --> 00:14:10,000
+Meanwhile, let's recap what we have learned today.
+
+201
+00:14:10,000 --> 00:14:13,000
+The Navy learned how we might interact with it.
+
+202
+00:14:13,000 --> 00:14:18,000
+With the help of a glimpse, we learned what views the clips we may use to execute to give commands.
+
+203
+00:14:19,000 --> 00:14:25,000
+Also today, you saw how you can execute basic operations from a collapse besides the collapse configuration.
+
+204
+00:14:25,000 --> 00:14:32,000
+We also learned how to use it directly from Eclipse today, where even did can commit and push that
+
+205
+00:14:32,000 --> 00:14:34,000
+snapshot to the remote repository.
+
+206
+00:14:34,000 --> 00:14:39,000
+And in the end of the lesson, I showed you how you might use magenta in eclipse.
+
+207
+00:14:39,000 --> 00:14:41,000
+Hope you enjoyed the lesson.
+
+208
+00:14:41,000 --> 00:14:44,000
+Thanks a lot for your attention and see you in the next lesson.
+

17 - GIT/external-links.txt

@@ -0,0 +1,9 @@
+
+002 Git-download-Web-site
+https://git-scm.com/downloads
+
+005 Git-ignore-for-different-languages
+https://github.com/github/gitignore
+
+009 -ls-command-details
+https://www.rapidtables.com/code/linux/ls.html

18 - Excpetion Handling/001 Exception Handling in Java_en.srt

@@ -0,0 +1,1500 @@
+1
+00:00:05,000 --> 00:00:06,000
+Hello there.
+
+2
+00:00:06,000 --> 00:00:10,000
+Students in this class and we are going to discuss an important topic, you would use knowledge from
+
+3
+00:00:10,000 --> 00:00:13,000
+this last year in your own life as a software engineer.
+
+4
+00:00:14,000 --> 00:00:17,000
+They will talk about exceptions and how to handle exceptions in Java.
+
+5
+00:00:17,000 --> 00:00:19,000
+I will explain what exceptions are.
+
+6
+00:00:20,000 --> 00:00:22,000
+We will talk about Iraqi of exceptions.
+
+7
+00:00:23,000 --> 00:00:24,000
+After this lesson.
+
+8
+00:00:24,000 --> 00:00:27,000
+You will understand what checked and checked exceptions are.
+
+9
+00:00:27,000 --> 00:00:30,000
+Besides all this, we are going to learn how to handle exceptions.
+
+10
+00:00:30,000 --> 00:00:35,000
+You'll learn what try catch block is and what finally block is well known.
+
+11
+00:00:35,000 --> 00:00:38,000
+Different variations of catch blocks in this lesson.
+
+12
+00:00:38,000 --> 00:00:42,000
+We'll also talk about how to declare that some method will throw exception.
+
+13
+00:00:43,000 --> 00:00:48,000
+You are going to learn what specific case was thrown exceptions during inheritance and methods of arriving.
+
+14
+00:00:48,000 --> 00:00:54,000
+And at the end of the lesson you learn how to create your own custom exceptions to meet the requirements
+
+15
+00:00:54,000 --> 00:00:55,000
+of business logic.
+
+16
+00:00:55,000 --> 00:01:00,000
+During the lesson I, I'll share with you best practices and tips how to work with exceptions in Java
+
+17
+00:01:00,000 --> 00:01:03,000
+to help you handle exceptions like approach.
+
+18
+00:01:03,000 --> 00:01:08,000
+Let's start from understanding what exceptions have explaining in simple words.
+
+19
+00:01:08,000 --> 00:01:14,000
+Imagine that you wrote the logic for your online store, and the content managers may now upload information
+
+20
+00:01:14,000 --> 00:01:21,000
+about products to your program manager, store information about products and specific files with GSV
+
+21
+00:01:21,000 --> 00:01:28,000
+format that is comma separated values format that is widely used in transferring and storing data will
+
+22
+00:01:28,000 --> 00:01:33,000
+face with files of such format in the near future will not focus on the specific file format.
+
+23
+00:01:34,000 --> 00:01:39,000
+Just imagine that managers can upload information with products to your program, bypassing a specific
+
+24
+00:01:39,000 --> 00:01:39,000
+file.
+
+25
+00:01:40,000 --> 00:01:46,000
+And what if manager parse the file name and file past that does not exist on the file system at all.
+
+26
+00:01:46,000 --> 00:01:48,000
+That is exceptional case.
+
+27
+00:01:48,000 --> 00:01:52,000
+Your program does not have predefined logic by default to handle that.
+
+28
+00:01:53,000 --> 00:01:54,000
+That is called exception.
+
+29
+00:01:55,000 --> 00:02:01,000
+Your program can't predict that users who will interact with your program will pass invalid link to
+
+30
+00:02:01,000 --> 00:02:02,000
+the file.
+
+31
+00:02:02,000 --> 00:02:06,000
+It is not an issue of your application that is technical limitations at all.
+
+32
+00:02:06,000 --> 00:02:08,000
+Users should respect.
+
+33
+00:02:09,000 --> 00:02:14,000
+But what to do in this case, they have to catch this exceptional case and write a code that will tell
+
+34
+00:02:14,000 --> 00:02:15,000
+what to do next.
+
+35
+00:02:15,000 --> 00:02:22,000
+In such cases, for example, do we want to inform our users that file does not exist and let him or
+
+36
+00:02:22,000 --> 00:02:24,000
+her to upload file one more time?
+
+37
+00:02:24,000 --> 00:02:29,000
+Or do we want to just ignore this fact and inform users at zero products added?
+
+38
+00:02:30,000 --> 00:02:36,000
+Product owners can come up with numerous cases how to handle this case from user experience site, but
+
+39
+00:02:36,000 --> 00:02:38,000
+we have to implement that.
+
+40
+00:02:38,000 --> 00:02:40,000
+Does this example make sense clearer?
+
+41
+00:02:40,000 --> 00:02:43,000
+Can you understand now what an exception is?
+
+42
+00:02:43,000 --> 00:02:47,000
+OK, if you understood this example, let's move on.
+
+43
+00:02:47,000 --> 00:02:50,000
+The next example would be a bit more technical.
+
+44
+00:02:50,000 --> 00:02:54,000
+That's why let me show it to you on the real code example.
+
+45
+00:02:55,000 --> 00:02:59,000
+Imagine that you implemented masses that should charge users during the checkout process.
+
+46
+00:03:00,000 --> 00:03:02,000
+We call it charge user.
+
+47
+00:03:02,000 --> 00:03:07,000
+And this matter takes user object as an argument, an amount of money to charge.
+
+48
+00:03:07,000 --> 00:03:15,000
+Specially for this example, I created simple class user that contains only one filled amount of money
+
+49
+00:03:15,000 --> 00:03:20,000
+and tumescence getter and setter to manipulate with the state of this type.
+
+50
+00:03:20,000 --> 00:03:24,000
+This simple user class will keep you focused on our example.
+
+51
+00:03:25,000 --> 00:03:28,000
+Imagine that we want to update amount of money in user object.
+
+52
+00:03:29,000 --> 00:03:35,000
+That's why you call Sattar Masset to set amount of money that is less than current amount by the order
+
+53
+00:03:35,000 --> 00:03:36,000
+price.
+
+54
+00:03:36,000 --> 00:03:41,000
+But for some reasons there is no user object behind this reference.
+
+55
+00:03:41,000 --> 00:03:42,000
+How this can happen?
+
+56
+00:03:43,000 --> 00:03:46,000
+There are dozens of reasons database didn't return.
+
+57
+00:03:46,000 --> 00:03:53,000
+The information about the user or some error happened on database site or in case you want to take information
+
+58
+00:03:53,000 --> 00:03:55,000
+about user from current obsession.
+
+59
+00:03:55,000 --> 00:03:59,000
+But user is locked out in another Web browser tab.
+
+60
+00:03:59,000 --> 00:04:05,000
+I can continue if you want, but I want you to understand that there are always chances that something
+
+61
+00:04:05,000 --> 00:04:05,000
+will go wrong.
+
+62
+00:04:06,000 --> 00:04:10,000
+And at the end of the day, user variable will reference to the null.
+
+63
+00:04:11,000 --> 00:04:12,000
+When will call mascot's on?
+
+64
+00:04:12,000 --> 00:04:13,000
+No reference.
+
+65
+00:04:13,000 --> 00:04:15,000
+We are going to have a new pointer exception.
+
+66
+00:04:16,000 --> 00:04:18,000
+Here's an example and main method.
+
+67
+00:04:18,000 --> 00:04:22,000
+You can see that I created a user variable that is reference to non-value.
+
+68
+00:04:23,000 --> 00:04:28,000
+That is just for the sake of example, in real life in this line can be retrieved the user from the
+
+69
+00:04:28,000 --> 00:04:32,000
+database or from the session for this example.
+
+70
+00:04:32,000 --> 00:04:33,000
+It doesn't matter.
+
+71
+00:04:33,000 --> 00:04:36,000
+And here I have order price.
+
+72
+00:04:36,000 --> 00:04:39,000
+I want to charge my user during the checkout.
+
+73
+00:04:39,000 --> 00:04:41,000
+I passed this variable to the it.
+
+74
+00:04:42,000 --> 00:04:43,000
+Can you guess what will happen?
+
+75
+00:04:44,000 --> 00:04:45,000
+You are right.
+
+76
+00:04:45,000 --> 00:04:48,000
+My program will be terminated because of Northpoint exception.
+
+77
+00:04:49,000 --> 00:04:53,000
+Let me run this program to prove this and here is no point the exception.
+
+78
+00:04:53,000 --> 00:05:01,000
+As I promised, I have it because I tried to call method some behavior on the object that doesn't exist.
+
+79
+00:05:02,000 --> 00:05:05,000
+So there are no methods for new values.
+
+80
+00:05:05,000 --> 00:05:12,000
+This is also exceptional case and our program program can't understand what it has to do in case there
+
+81
+00:05:12,000 --> 00:05:13,000
+is no object.
+
+82
+00:05:14,000 --> 00:05:19,000
+And now, when you understood what an exception is, let's categorize them.
+
+83
+00:05:20,000 --> 00:05:21,000
+There are two groups.
+
+84
+00:05:21,000 --> 00:05:23,000
+Have exceptions checked and checked.
+
+85
+00:05:23,000 --> 00:05:25,000
+What is the difference between them?
+
+86
+00:05:25,000 --> 00:05:28,000
+Let me explain in simple words, no point.
+
+87
+00:05:28,000 --> 00:05:31,000
+The exception that you saw is unchecked exception.
+
+88
+00:05:32,000 --> 00:05:34,000
+It isn't checked during compilation time.
+
+89
+00:05:35,000 --> 00:05:38,000
+Moreover, why it should be checked at compile time.
+
+90
+00:05:38,000 --> 00:05:45,000
+If a developer wants to call Masset on some object developer should ensure that the rest of the program
+
+91
+00:05:45,000 --> 00:05:47,000
+is written in the way to pass.
+
+92
+00:05:47,000 --> 00:05:50,000
+Not no value to this method.
+
+93
+00:05:50,000 --> 00:05:55,000
+And if there is now there is no error of user interaction with the program.
+
+94
+00:05:55,000 --> 00:05:58,000
+There is a defect in the way how program is written.
+
+95
+00:05:59,000 --> 00:06:04,000
+On the other hand, check the exception is an exceptional case that is checked during compilation time.
+
+96
+00:06:05,000 --> 00:06:11,000
+For example, user pass the filename to read from these kind of errors is checked at compile time.
+
+97
+00:06:12,000 --> 00:06:12,000
+Why?
+
+98
+00:06:13,000 --> 00:06:19,000
+Because in this case there could be case when the user will pass the filename that doesn't exist and
+
+99
+00:06:19,000 --> 00:06:23,000
+this case is obvious and it doesn't depend on developer.
+
+100
+00:06:23,000 --> 00:06:29,000
+So check the exceptions exist to predict errors of user interaction with the program and they can be
+
+101
+00:06:29,000 --> 00:06:32,000
+verified at compile time and check.
+
+102
+00:06:32,000 --> 00:06:38,000
+The exceptions usually appear during the runtime and can't be checked beforehand.
+
+103
+00:06:38,000 --> 00:06:42,000
+Can you understand now what checked and checked exceptions are?
+
+104
+00:06:43,000 --> 00:06:49,000
+You already saw no pointer exception and understood and checked exceptions before learning of Iraqi
+
+105
+00:06:49,000 --> 00:06:50,000
+exceptions and details.
+
+106
+00:06:50,000 --> 00:06:54,000
+I'm one of you understand example of checked exception.
+
+107
+00:06:54,000 --> 00:07:00,000
+Sheizaf files class that contains Massud to read the content of the files and write content through
+
+108
+00:07:00,000 --> 00:07:01,000
+the files.
+
+109
+00:07:01,000 --> 00:07:08,000
+Imagine that we want to read text from file and here instead of this text, it can be that I have some
+
+110
+00:07:08,000 --> 00:07:11,000
+variables that is passed to my program by user, for example.
+
+111
+00:07:11,000 --> 00:07:19,000
+And you can see that in this case there is a compilation error unhandled exception of Type II or exception.
+
+112
+00:07:19,000 --> 00:07:26,000
+And you can see that compiler checks a potential exception and compiler insists on Hanlon's exception.
+
+113
+00:07:27,000 --> 00:07:32,000
+In other words, Compiler wants us to write the code here that would tell what to do in case the file
+
+114
+00:07:32,000 --> 00:07:33,000
+wasn't found.
+
+115
+00:07:34,000 --> 00:07:38,000
+So one of our tasks today also to learn how to handle exceptions in Java.
+
+116
+00:07:38,000 --> 00:07:44,000
+But before that, I want to complete the topic of exceptions in Iraq to make sure you understood it.
+
+117
+00:07:45,000 --> 00:07:51,000
+So you already shown real examples of what is checked and unchecked exceptions and what does that mean?
+
+118
+00:07:51,000 --> 00:07:57,000
+Now, let's look at exceptions, the Iraqis to understand what types of exceptions exist and whether
+
+119
+00:07:57,000 --> 00:07:58,000
+they are checked on, checked.
+
+120
+00:07:59,000 --> 00:08:02,000
+And you already know everything in Java is an object.
+
+121
+00:08:02,000 --> 00:08:06,000
+That means how exceptions are also objects of specific type.
+
+122
+00:08:07,000 --> 00:08:15,000
+That's why on this slide, you can see Iraqi of classes that are used to create exception objects on
+
+123
+00:08:15,000 --> 00:08:16,000
+top of the Iraqi.
+
+124
+00:08:16,000 --> 00:08:22,000
+We have Straubel class that is basic class for all exceptions and instances of this type.
+
+125
+00:08:22,000 --> 00:08:23,000
+I checked exceptions.
+
+126
+00:08:24,000 --> 00:08:27,000
+Throw will is extended by two Ozeki types.
+
+127
+00:08:27,000 --> 00:08:33,000
+They are error and exception, error type and all the descendants unchecked.
+
+128
+00:08:33,000 --> 00:08:34,000
+Why?
+
+129
+00:08:34,000 --> 00:08:40,000
+Because errors are type of exceptional cases in our program execution when something went completely
+
+130
+00:08:40,000 --> 00:08:43,000
+wrong and there is no chance to fix this already.
+
+131
+00:08:44,000 --> 00:08:50,000
+There is no need to handle this type of exceptional case because you even won't be able to do anything,
+
+132
+00:08:51,000 --> 00:08:53,000
+for example, out of memory error.
+
+133
+00:08:53,000 --> 00:08:59,000
+If you are in the position when you run out of memory, there is even no memory for you to create a
+
+134
+00:08:59,000 --> 00:09:00,000
+new object.
+
+135
+00:09:00,000 --> 00:09:01,000
+This makes sense.
+
+136
+00:09:02,000 --> 00:09:04,000
+Another example is stack overflow error.
+
+137
+00:09:05,000 --> 00:09:06,000
+It is thrown by GM.
+
+138
+00:09:06,000 --> 00:09:10,000
+When Stack memory's finished, Sarat Das error is thrown.
+
+139
+00:09:10,000 --> 00:09:15,000
+When you try to invoke a method on the threat of executions, it was already stopped.
+
+140
+00:09:15,000 --> 00:09:18,000
+And again, there is nothing you can do about this.
+
+141
+00:09:18,000 --> 00:09:26,000
+That's why all errors and checked and another Iraqi is Iraqi of exception types on the sense of exception
+
+142
+00:09:26,000 --> 00:09:30,000
+type beside the sentence of runtime exception type.
+
+143
+00:09:30,000 --> 00:09:34,000
+I checked and only runtime exception was its descendants is unchecked.
+
+144
+00:09:35,000 --> 00:09:37,000
+That is something that we just have to remember.
+
+145
+00:09:38,000 --> 00:09:45,000
+I know that this might seem not logical to you, but it is as it is, the most popular checked exceptions
+
+146
+00:09:45,000 --> 00:09:51,000
+that extended from exception type a group of I o exceptions, those exceptions that are associated with
+
+147
+00:09:51,000 --> 00:09:53,000
+input output streams.
+
+148
+00:09:53,000 --> 00:09:56,000
+Also, there are a group of checked Ezekial exceptions.
+
+149
+00:09:57,000 --> 00:10:01,000
+Additionally, you can explore Iraqian your source code edit by reviewing.
+
+150
+00:10:01,000 --> 00:10:08,000
+Iraq exceptions, if you missed the lesson when I explained how to do that, I will show you this in
+
+151
+00:10:08,000 --> 00:10:14,000
+the minute and runtime exceptions, those exceptions that are not checked by the compiler during the
+
+152
+00:10:14,000 --> 00:10:20,000
+compilation process, there are such exceptions as no pointer exception as we already sort of the arithmetic
+
+153
+00:10:20,000 --> 00:10:21,000
+exception.
+
+154
+00:10:21,000 --> 00:10:28,000
+So that's when we divided into zero class cast exceptions at the throne when it is not possible to cast
+
+155
+00:10:28,000 --> 00:10:30,000
+types illegal argument exception.
+
+156
+00:10:30,000 --> 00:10:34,000
+No such aliment exception array index out of bounds exception.
+
+157
+00:10:35,000 --> 00:10:39,000
+Those are all unchecked exceptions that are consequences of development errors.
+
+158
+00:10:40,000 --> 00:10:48,000
+Compiler won't be able to check those because those that can be identified only during the runtime.
+
+159
+00:10:48,000 --> 00:10:55,000
+Is it clear also now when we learned a hierarchy of exceptions, it is time to start look at examples
+
+160
+00:10:55,000 --> 00:10:58,000
+and understand how we can handle exceptions.
+
+161
+00:10:58,000 --> 00:11:04,000
+By the way, before we start, I promised to show you how you can explore type hierarchy in idea.
+
+162
+00:11:04,000 --> 00:11:10,000
+First of all, I open a type, I press control shift and simultaneously to open exception type.
+
+163
+00:11:11,000 --> 00:11:15,000
+And when I open the exception type, I press F for key.
+
+164
+00:11:16,000 --> 00:11:22,000
+And here on the left you can see that I opened type Iraqi and I can scroll and navigate here to explore
+
+165
+00:11:22,000 --> 00:11:24,000
+hierarchy of type exception.
+
+166
+00:11:25,000 --> 00:11:27,000
+Hobbs's will help you during your self application.
+
+167
+00:11:28,000 --> 00:11:30,000
+And now let's get back to exceptions handlin.
+
+168
+00:11:31,000 --> 00:11:35,000
+As we already discussed, there is not so much sense to handle and exception.
+
+169
+00:11:36,000 --> 00:11:39,000
+You still can do that for some specific reasons if you want.
+
+170
+00:11:39,000 --> 00:11:45,000
+But in most cases it is better to fix your code, not face with runtime exceptions at all.
+
+171
+00:11:45,000 --> 00:11:52,000
+That's why during the next examples, I'm going to use checked exceptions for the purposes the remember
+
+172
+00:11:52,000 --> 00:11:55,000
+example with reading files that doesn't exist.
+
+173
+00:11:56,000 --> 00:11:59,000
+Let me show you now how we can handle that exception.
+
+174
+00:11:59,000 --> 00:12:04,000
+You have to surround the code that potentially can throw an exception with try catch block.
+
+175
+00:12:05,000 --> 00:12:06,000
+The syntax is simple.
+
+176
+00:12:07,000 --> 00:12:07,000
+You're right.
+
+177
+00:12:07,000 --> 00:12:09,000
+Try keyword followed by braze.
+
+178
+00:12:10,000 --> 00:12:14,000
+After that goes code that potentially can throw an exception.
+
+179
+00:12:14,000 --> 00:12:21,000
+And after that you write catch keyword and declare a local variable of type that you want to catch.
+
+180
+00:12:21,000 --> 00:12:29,000
+In our particular case, we want to catch I o exception in case exceptions will be thrown will get into
+
+181
+00:12:29,000 --> 00:12:30,000
+this block.
+
+182
+00:12:30,000 --> 00:12:39,000
+So here object of I o exception will be created in this local variable will be used to get access to
+
+183
+00:12:39,000 --> 00:12:40,000
+the exception object.
+
+184
+00:12:41,000 --> 00:12:44,000
+Why do I need this in real life.
+
+185
+00:12:44,000 --> 00:12:46,000
+You use reference to the exception.
+
+186
+00:12:46,000 --> 00:12:53,000
+Object to look stack trace interviewed later here for the sake of example, I retrieve an array of stack
+
+187
+00:12:53,000 --> 00:12:55,000
+trace elements and print it in one line.
+
+188
+00:12:56,000 --> 00:12:59,000
+Also you can get the root cause of the error in case there are any.
+
+189
+00:13:00,000 --> 00:13:05,000
+I'll get mad if there is any further debugging purposes we can print, stack, trace to console.
+
+190
+00:13:06,000 --> 00:13:12,000
+Let me run this program to show you that we enter it catch block and here you can see text that we printed
+
+191
+00:13:12,000 --> 00:13:14,000
+to console from our catch block.
+
+192
+00:13:15,000 --> 00:13:18,000
+Can I understand now how you can catch exceptions?
+
+193
+00:13:18,000 --> 00:13:21,000
+If yes, then let's press it now.
+
+194
+00:13:21,000 --> 00:13:23,000
+Let me show you another example.
+
+195
+00:13:23,000 --> 00:13:28,000
+There is another syntax that allows you to use multiple exceptions in catch clause.
+
+196
+00:13:29,000 --> 00:13:30,000
+Let me open another file.
+
+197
+00:13:31,000 --> 00:13:38,000
+Imagine that you wrote code to handle an exception, but now we also have code to get connection to
+
+198
+00:13:38,000 --> 00:13:39,000
+the database.
+
+199
+00:13:39,000 --> 00:13:43,000
+This Masset get connection also can throw an exception.
+
+200
+00:13:44,000 --> 00:13:47,000
+That's why you have to handle potential Ezekial exception.
+
+201
+00:13:48,000 --> 00:13:50,000
+There are two options to do that.
+
+202
+00:13:50,000 --> 00:13:55,000
+You can add an exception to existing clause like this by using or operator.
+
+203
+00:13:56,000 --> 00:14:03,000
+In this case, I tell that this variable E will be either of Type II or exception or Ezekial exception
+
+204
+00:14:03,000 --> 00:14:06,000
+because in the case exception will be thrown in.
+
+205
+00:14:06,000 --> 00:14:11,000
+This line will instantly get to the cadge block and we will catch I.
+
+206
+00:14:11,000 --> 00:14:17,000
+O exception and case exception will happen and this line will get to catch block and will have Ezekial
+
+207
+00:14:17,000 --> 00:14:18,000
+exception.
+
+208
+00:14:18,000 --> 00:14:25,000
+This syntax works just fine if you want to program the same behavior for multiple errors, for example,
+
+209
+00:14:26,000 --> 00:14:28,000
+if have one, just log error and that's it.
+
+210
+00:14:29,000 --> 00:14:34,000
+But in case you want to implement different logic, to handle different exceptions, you have to implement
+
+211
+00:14:34,000 --> 00:14:35,000
+different cadge block.
+
+212
+00:14:36,000 --> 00:14:42,000
+For example, in the first case, let's notify users that this file doesn't exist and ask user to provide
+
+213
+00:14:42,000 --> 00:14:44,000
+a path to a new file.
+
+214
+00:14:44,000 --> 00:14:50,000
+In either case, let's notify users that there is an error with database and there is nothing.
+
+215
+00:14:50,000 --> 00:14:53,000
+What user can do about this doesn't make sense.
+
+216
+00:14:53,000 --> 00:14:59,000
+Can you understand now when to use sketchbook with multiple exception types and when to use multiple
+
+217
+00:14:59,000 --> 00:15:01,000
+catch blocks also?
+
+218
+00:15:01,000 --> 00:15:02,000
+Let's move on.
+
+219
+00:15:03,000 --> 00:15:08,000
+There is one more rule for multiple catch blocks in case there are potentially two types of exceptions
+
+220
+00:15:08,000 --> 00:15:15,000
+that are from the same Iraqi, you have to specify the more specific type first and only after that
+
+221
+00:15:15,000 --> 00:15:17,000
+specified the most generic time.
+
+222
+00:15:17,000 --> 00:15:19,000
+Let me show you this one example.
+
+223
+00:15:19,000 --> 00:15:25,000
+Imagine that this line can throw an exception and constructor of a file reader can throw a file not
+
+224
+00:15:25,000 --> 00:15:28,000
+found exception, and we can write multiple catch blocks.
+
+225
+00:15:29,000 --> 00:15:35,000
+But important thing here is that Philmont found exception is a shell type of IO exception.
+
+226
+00:15:36,000 --> 00:15:40,000
+When exceptions will be thrown, each catch close will be checked.
+
+227
+00:15:40,000 --> 00:15:47,000
+That's why you can specify Kedge Block with all exceptions, before Kedge Block, which Philmont found
+
+228
+00:15:47,000 --> 00:15:47,000
+exception.
+
+229
+00:15:48,000 --> 00:15:54,000
+In this case, you're going to have compilation error unreachable catch block because exceptions will
+
+230
+00:15:54,000 --> 00:15:58,000
+be handled by the first KEDGE block with generic exception.
+
+231
+00:15:58,000 --> 00:16:02,000
+Type Lekman common this code to show you this compilation error.
+
+232
+00:16:02,000 --> 00:16:06,000
+And here you can see unreachable kedge block and error.
+
+233
+00:16:06,000 --> 00:16:12,000
+This example is very popular in tests during the interview, so please remember that.
+
+234
+00:16:12,000 --> 00:16:17,000
+OK, if you understood how to work with multiple kedge blocks, let's look at the next example.
+
+235
+00:16:18,000 --> 00:16:22,000
+Before the lesson, I also created another file to them and use the next case.
+
+236
+00:16:23,000 --> 00:16:28,000
+Now I want to review as you try Keje finally construction by default.
+
+237
+00:16:28,000 --> 00:16:31,000
+Finally Blac will be executed with and without exception.
+
+238
+00:16:32,000 --> 00:16:33,000
+Here you can see the same case.
+
+239
+00:16:33,000 --> 00:16:35,000
+But with Finally Block.
+
+240
+00:16:35,000 --> 00:16:39,000
+Let me around this program again and here and console.
+
+241
+00:16:39,000 --> 00:16:44,000
+You can see the text that we printed from our final block right after the stack trace.
+
+242
+00:16:44,000 --> 00:16:47,000
+In some particular case you can use try finally block.
+
+243
+00:16:48,000 --> 00:16:52,000
+Let me comment these lines and you can see there is no compilation error.
+
+244
+00:16:53,000 --> 00:16:59,000
+Usually we use final blog to perform operations that should be executed no matter what happened.
+
+245
+00:17:00,000 --> 00:17:02,000
+Is the exception happened or not?
+
+246
+00:17:02,000 --> 00:17:04,000
+The code from Final Lock should be executed.
+
+247
+00:17:05,000 --> 00:17:09,000
+For example, in the past, final block used to close input output streams.
+
+248
+00:17:10,000 --> 00:17:14,000
+Now Thrivers Resources Block is used to close resources automatically.
+
+249
+00:17:14,000 --> 00:17:20,000
+I'll show you that during the lesson about input output streams today, you can use final block to release
+
+250
+00:17:20,000 --> 00:17:22,000
+some critical resources.
+
+251
+00:17:23,000 --> 00:17:29,000
+Finally, Block will be executed all the times, but there are some exceptions that can prevent you
+
+252
+00:17:29,000 --> 00:17:29,000
+from executing.
+
+253
+00:17:29,000 --> 00:17:31,000
+Finally, block till the end.
+
+254
+00:17:31,000 --> 00:17:34,000
+Let's quickly review these cases.
+
+255
+00:17:34,000 --> 00:17:40,000
+The first case finally block won't be executed in case program is stopped and finally block.
+
+256
+00:17:41,000 --> 00:17:43,000
+That is the case when we stopped giving.
+
+257
+00:17:43,000 --> 00:17:50,000
+Our final block won't be executed till the end in case some exception will happen inside the final block.
+
+258
+00:17:51,000 --> 00:17:57,000
+Also, in case you have noticed, writing the program final block will be executed till the end in case
+
+259
+00:17:57,000 --> 00:17:58,000
+Read will be terminated.
+
+260
+00:17:59,000 --> 00:18:02,000
+Now, I believe you know everything about final blocks.
+
+261
+00:18:02,000 --> 00:18:03,000
+Let's move on.
+
+262
+00:18:03,000 --> 00:18:07,000
+I want to tell you now about Suros Keever, for example.
+
+263
+00:18:07,000 --> 00:18:12,000
+Let me open the source code of Red Alliance Macit here you can see Suros Keevers.
+
+264
+00:18:13,000 --> 00:18:14,000
+What does that mean?
+
+265
+00:18:14,000 --> 00:18:20,000
+That means that this Masset potentially can throw an exception in their custom matters.
+
+266
+00:18:20,000 --> 00:18:27,000
+You would also like to specify that some suros exception if you want to warn all clients of your code
+
+267
+00:18:27,000 --> 00:18:29,000
+to handle some specific cases.
+
+268
+00:18:30,000 --> 00:18:33,000
+In this case it is specified that I have to handle I o exception.
+
+269
+00:18:34,000 --> 00:18:39,000
+Now let's create custom method and declare Tetsuro exception.
+
+270
+00:18:39,000 --> 00:18:43,000
+I open another demo files that I prepared before this lesson.
+
+271
+00:18:43,000 --> 00:18:48,000
+You will be able to find reference to all files from the lesson in the lesson attachments.
+
+272
+00:18:49,000 --> 00:18:51,000
+In this example in class throws Damos.
+
+273
+00:18:51,000 --> 00:18:55,000
+I have some methods that throws file not found exception.
+
+274
+00:18:55,000 --> 00:19:02,000
+After that I create an object of throws them a class and call some Macit Letterman.
+
+275
+00:19:02,000 --> 00:19:09,000
+Command this line and you can see that there is a compilation error because I have to handle potential
+
+276
+00:19:09,000 --> 00:19:15,000
+error and I have to do that even in case I don't have any code in this matter at all.
+
+277
+00:19:15,000 --> 00:19:21,000
+So this declaration is like a warning for everyone who is going to use this method.
+
+278
+00:19:22,000 --> 00:19:27,000
+There is some rule that we all have to know while overwriting methods that throw exception.
+
+279
+00:19:28,000 --> 00:19:31,000
+Let me show it to you on the example in this file.
+
+280
+00:19:31,000 --> 00:19:36,000
+For the sake of the demo, I created one more class that extends through them a class.
+
+281
+00:19:37,000 --> 00:19:39,000
+And I want to write some method.
+
+282
+00:19:39,000 --> 00:19:45,000
+And you can see that I don't necessarily have to add Suros declaration here, and that is fine.
+
+283
+00:19:45,000 --> 00:19:49,000
+I can Atheros declaration if I want one second.
+
+284
+00:19:49,000 --> 00:19:50,000
+Let me add it here.
+
+285
+00:19:51,000 --> 00:19:57,000
+Now, this method also suros file and found exception Massaro as an exception.
+
+286
+00:19:58,000 --> 00:19:59,000
+What about I o exception.
+
+287
+00:20:00,000 --> 00:20:00,000
+Let me try.
+
+288
+00:20:01,000 --> 00:20:07,000
+And now we can see compilation error, exception, IO exception is not compatible with throws clothes
+
+289
+00:20:07,000 --> 00:20:09,000
+and throws them as a method.
+
+290
+00:20:09,000 --> 00:20:11,000
+Now, you know the rule.
+
+291
+00:20:11,000 --> 00:20:17,000
+If you want to declare that some method throws exception and one of the rules for overridden Macit,
+
+292
+00:20:18,000 --> 00:20:23,000
+you have to specify compatible type of exception was the one from original master.
+
+293
+00:20:23,000 --> 00:20:31,000
+So in this case we can specify is a file not found exception or some child of violence found exception.
+
+294
+00:20:32,000 --> 00:20:38,000
+This type of exception doesn't have any child types, but we can create if we want to remove this rose
+
+295
+00:20:38,000 --> 00:20:39,000
+declaration.
+
+296
+00:20:40,000 --> 00:20:46,000
+Now, you know what Sarah's key word means, what to do in case you want to start program execution,
+
+297
+00:20:46,000 --> 00:20:51,000
+in case there is some error, you have to throw an exception how to do that.
+
+298
+00:20:52,000 --> 00:20:56,000
+Let me show it to you and navigate to file was the new example.
+
+299
+00:20:56,000 --> 00:21:01,000
+Imagine that we have mastered that can transfer money from one account to another.
+
+300
+00:21:01,000 --> 00:21:03,000
+It is called transfer money.
+
+301
+00:21:04,000 --> 00:21:09,000
+It gets account from account to and money to transfer amount.
+
+302
+00:21:09,000 --> 00:21:14,000
+By the way, for the sake of the drama, I created account class here in the same file.
+
+303
+00:21:14,000 --> 00:21:21,000
+And the rule of thumb is to validate that all arguments are valid and we can work with them here.
+
+304
+00:21:21,000 --> 00:21:25,000
+You can see if close where I check that from.
+
+305
+00:21:25,000 --> 00:21:32,000
+And two accounts are not you and that from account has enough money to perform a transaction in case
+
+306
+00:21:32,000 --> 00:21:34,000
+is in one of these statements is true.
+
+307
+00:21:34,000 --> 00:21:41,000
+That means that one of the argument is invalid and we can't proceed with this mass execution.
+
+308
+00:21:41,000 --> 00:21:46,000
+That's why I want to stop program execution with illegal argument exception.
+
+309
+00:21:46,000 --> 00:21:50,000
+I read through keyword and create an instance of a legal argument exception.
+
+310
+00:21:51,000 --> 00:21:56,000
+I can use any instance of any type that extends through class after a keyword.
+
+311
+00:21:56,000 --> 00:22:00,000
+In this particular case, I use already predefined type of exception.
+
+312
+00:22:01,000 --> 00:22:05,000
+Let me execute program and call this method with no accounts.
+
+313
+00:22:05,000 --> 00:22:08,000
+And I can see here a legal argument exception.
+
+314
+00:22:09,000 --> 00:22:11,000
+That is how you can throw an exception.
+
+315
+00:22:11,000 --> 00:22:13,000
+Your wish is that clear.
+
+316
+00:22:14,000 --> 00:22:19,000
+Take pause and think for a second about this construction if you understood it.
+
+317
+00:22:19,000 --> 00:22:26,000
+Let me explain this and next thing, each type of stromal has constructor that takes string as an argument.
+
+318
+00:22:26,000 --> 00:22:29,000
+This string is used as a message to our exception.
+
+319
+00:22:30,000 --> 00:22:37,000
+Let me add here in constructor, same message, for example, invalid arguments and let me execute this
+
+320
+00:22:37,000 --> 00:22:38,000
+program again.
+
+321
+00:22:38,000 --> 00:22:42,000
+And here in the sector race, you can see explanatory message.
+
+322
+00:22:42,000 --> 00:22:49,000
+Moreover, in case someone would like to catch this exception, each will has mastered get message.
+
+323
+00:22:49,000 --> 00:22:51,000
+This can return the string.
+
+324
+00:22:51,000 --> 00:22:54,000
+But this is only in case you want to retrieve this message.
+
+325
+00:22:55,000 --> 00:22:56,000
+What else we can do?
+
+326
+00:22:57,000 --> 00:23:01,000
+Sometimes developers drop checked exception with and checked.
+
+327
+00:23:01,000 --> 00:23:08,000
+When we have to do this, we have to do this in case when we have to throw exceptions during the implementation
+
+328
+00:23:08,000 --> 00:23:11,000
+of the method that does not allow us to throw exceptions.
+
+329
+00:23:12,000 --> 00:23:12,000
+But we should.
+
+330
+00:23:13,000 --> 00:23:19,000
+This is really a specific case, but will face with it the first time when we will learn the same topic.
+
+331
+00:23:20,000 --> 00:23:20,000
+I will explain.
+
+332
+00:23:20,000 --> 00:23:21,000
+Is it run?
+
+333
+00:23:21,000 --> 00:23:26,000
+Masset in Runnable interface doesn't throw exceptions, but sometimes we have to.
+
+334
+00:23:27,000 --> 00:23:29,000
+There are also some other cases.
+
+335
+00:23:30,000 --> 00:23:33,000
+I want you to learn this trick and use it when it is needed.
+
+336
+00:23:34,000 --> 00:23:37,000
+Let me come on this line and explain how it works.
+
+337
+00:23:38,000 --> 00:23:42,000
+Each Wrobel type has a constructor that takes us as Wrobel as an argument.
+
+338
+00:23:43,000 --> 00:23:50,000
+This is used when we want to set an original course for the exception here I a runtime exception and
+
+339
+00:23:50,000 --> 00:23:53,000
+posta is constructor a regional exception.
+
+340
+00:23:54,000 --> 00:23:57,000
+Let me run the program now and here and council.
+
+341
+00:23:57,000 --> 00:24:03,000
+You can see that runtime exception was caused by file not found exception.
+
+342
+00:24:03,000 --> 00:24:08,000
+In case somebody would catch this error, he can extract course.
+
+343
+00:24:08,000 --> 00:24:15,000
+Every type of Wrobel has a method yet cause that can return the reference to a regional exception.
+
+344
+00:24:15,000 --> 00:24:19,000
+So that's how you can rub checked exception with and checked exception.
+
+345
+00:24:20,000 --> 00:24:27,000
+And the last but not least for today, I want to teach you how to create your custom exceptions in case
+
+346
+00:24:27,000 --> 00:24:33,000
+you want to express some specific case and business logic with your custom type of exception, you have
+
+347
+00:24:33,000 --> 00:24:34,000
+to decide first.
+
+348
+00:24:34,000 --> 00:24:37,000
+You want to create checks or inject exception.
+
+349
+00:24:38,000 --> 00:24:44,000
+To create an unchecked exception, we have to declare our class that extends runtime exception in case
+
+350
+00:24:44,000 --> 00:24:46,000
+we want to implement and checked exception.
+
+351
+00:24:46,000 --> 00:24:52,000
+As I said, let me open a class with declaration of customer exception here we have not enough money
+
+352
+00:24:52,000 --> 00:24:53,000
+exception.
+
+353
+00:24:53,000 --> 00:24:57,000
+It is unchecked because it extends runtime exception.
+
+354
+00:24:57,000 --> 00:25:03,000
+In case you want to implement checked exception, you have to just extend your custom class from exception
+
+355
+00:25:03,000 --> 00:25:04,000
+type.
+
+356
+00:25:04,000 --> 00:25:07,000
+That's all easy, don't you think?
+
+357
+00:25:07,000 --> 00:25:12,000
+So for the sake of our Demmer, I'm going to keep not enough money exception unchecked.
+
+358
+00:25:13,000 --> 00:25:18,000
+And now when we have our custom exception, let me look at another version of the transfer money.
+
+359
+00:25:19,000 --> 00:25:24,000
+And this version was throw a legal argument, exceptional case from and to accounts.
+
+360
+00:25:24,000 --> 00:25:30,000
+And now and in case there is not enough money on the account from any transaction, we throw our custom
+
+361
+00:25:30,000 --> 00:25:32,000
+exception, not enough money exception.
+
+362
+00:25:32,000 --> 00:25:38,000
+Hobe, this example helps you understand when we might want to use custom exceptions and how we can
+
+363
+00:25:38,000 --> 00:25:39,000
+do that.
+
+364
+00:25:40,000 --> 00:25:42,000
+Now, let's review what we have learned today.
+
+365
+00:25:43,000 --> 00:25:44,000
+Today, we learned a lot of things.
+
+366
+00:25:45,000 --> 00:25:48,000
+Now, you know, what exceptions are we learned in Iraq?
+
+367
+00:25:48,000 --> 00:25:54,000
+Have exceptions also, you learned what checked and checked exceptions are one examples.
+
+368
+00:25:54,000 --> 00:25:56,000
+We learned how to handle exceptions.
+
+369
+00:25:56,000 --> 00:26:02,000
+You saw how we can use try to catch blogs and try catch finally blogs to handle exceptions.
+
+370
+00:26:02,000 --> 00:26:07,000
+In this lesson, you learned what Suros keywords is and how we can use it.
+
+371
+00:26:07,000 --> 00:26:13,000
+We learned how to throw exceptions when we need, and at the end of the lesson we learned how to create
+
+372
+00:26:13,000 --> 00:26:16,000
+our custom checked or unchecked exception.
+
+373
+00:26:16,000 --> 00:26:19,000
+Hope you found this lesson useful for you.
+
+374
+00:26:19,000 --> 00:26:21,000
+Thanks a lot for your attention.
+
+375
+00:26:21,000 --> 00:26:23,000
+See you in the next lesson.
+

18 - Excpetion Handling/001 Source-code-of-all-examples-from-the-lesson.url

@@ -0,0 +1,2 @@
+[InternetShortcut]
+URL=https://github.com/AndriiPiatakha/learnit_java_core/tree/master/src/com/itbulls/learnit/javacore/exceptions

18 - Excpetion Handling/external-links.txt

@@ -0,0 +1,3 @@
+
+001 Source-code-of-all-examples-from-the-lesson
+https://github.com/AndriiPiatakha/learnit_java_core/tree/master/src/com/itbulls/learnit/javacore/exceptions

19 - Java Collections Framework/001 Java Collections Framework Overview_en.srt

@@ -0,0 +1,508 @@
+1
+00:00:06,000 --> 00:00:06,000
+Hello.
+
+2
+00:00:06,000 --> 00:00:10,000
+Students in this region, I'm going to make overview of Java collections framework.
+
+3
+00:00:10,000 --> 00:00:15,000
+I want you to understand general structure of Java collections framework before we start going deeper
+
+4
+00:00:15,000 --> 00:00:16,000
+in the details.
+
+5
+00:00:16,000 --> 00:00:18,000
+And here's our agenda for the day.
+
+6
+00:00:18,000 --> 00:00:21,000
+We'll talk about what GSF includes in this lesson.
+
+7
+00:00:21,000 --> 00:00:24,000
+You are going to learn the difference between collections and the rates.
+
+8
+00:00:24,000 --> 00:00:28,000
+We are going to discuss what advantages collections have over their rates.
+
+9
+00:00:28,000 --> 00:00:34,000
+Also, during the lesson, we are going to talk about two separate Iraqis in Java collections framework
+
+10
+00:00:34,000 --> 00:00:37,000
+that Zeta's Iraqi of collections and hierarchy of maps.
+
+11
+00:00:37,000 --> 00:00:39,000
+And what are the difference between them?
+
+12
+00:00:39,000 --> 00:00:44,000
+I believe this is going to help you significantly to understand the core structure and the next lessons
+
+13
+00:00:44,000 --> 00:00:45,000
+in general.
+
+14
+00:00:45,000 --> 00:00:50,000
+So let's start and to start with let's answer the question.
+
+15
+00:00:50,000 --> 00:00:54,000
+What does you see, if I will shut and Java collections framework, if you don't mind.
+
+16
+00:00:54,000 --> 00:00:56,000
+What does it consist of?
+
+17
+00:00:56,000 --> 00:01:02,000
+GCF is a unified name for the group of the types and algorithms that are developed to store elements
+
+18
+00:01:02,000 --> 00:01:05,000
+in them and perform manipulations on the group of the objects.
+
+19
+00:01:06,000 --> 00:01:10,000
+GCF includes next things, collection interfaces.
+
+20
+00:01:10,000 --> 00:01:16,000
+These are abstract data types that describes the type that my group, multiple elements in the single
+
+21
+00:01:16,000 --> 00:01:21,000
+unit as a software engineer, are going to use collections all the times to perform operations with
+
+22
+00:01:21,000 --> 00:01:26,000
+the group of objects, for example, product list in our Web application.
+
+23
+00:01:26,000 --> 00:01:32,000
+This might be a collection of products in the language of Java, and we could perform operations on
+
+24
+00:01:32,000 --> 00:01:37,000
+the group of the products, for example, search products, or filter them to keep only products that
+
+25
+00:01:37,000 --> 00:01:43,000
+has priced more than ten dollars or split all the group of products on the equal chance to show products
+
+26
+00:01:43,000 --> 00:01:45,000
+page by page and a lot of other things.
+
+27
+00:01:46,000 --> 00:01:49,000
+Can you understand now why we might need collections?
+
+28
+00:01:50,000 --> 00:01:51,000
+You might think.
+
+29
+00:01:51,000 --> 00:01:56,000
+Isn't that the same what we have arrays for take into account you used to raise already?
+
+30
+00:01:56,000 --> 00:02:02,000
+You might think that for the same purposes you would use arrays a bit later when we would talk about
+
+31
+00:02:02,000 --> 00:02:04,000
+advantages of collections of arrays.
+
+32
+00:02:04,000 --> 00:02:10,000
+You would understand why arrays and collections are two different things implementations of collection
+
+33
+00:02:10,000 --> 00:02:16,000
+interfaces, even despite the fact that abstractions for collections looks the same, the implementation
+
+34
+00:02:16,000 --> 00:02:20,000
+of this interface at different and fits for different goals.
+
+35
+00:02:20,000 --> 00:02:26,000
+For example, some collections work the best for adding new elements since the end of the collection,
+
+36
+00:02:26,000 --> 00:02:31,000
+and developers like that collections because of the constant time of retrieving element from them.
+
+37
+00:02:31,000 --> 00:02:36,000
+Are the collections work better when you need to add elements in the middle or at the beginning of the
+
+38
+00:02:36,000 --> 00:02:37,000
+collection?
+
+39
+00:02:38,000 --> 00:02:41,000
+Other collections work the best in the current environment.
+
+40
+00:02:41,000 --> 00:02:46,000
+We are going to learn all of these collections and to understand the difference when to use each collection
+
+41
+00:02:46,000 --> 00:02:47,000
+type.
+
+42
+00:02:48,000 --> 00:02:55,000
+Map interfaces, map interface at different from collections in one important think map is a container
+
+43
+00:02:55,000 --> 00:02:58,000
+that contains pairs of key and value.
+
+44
+00:02:59,000 --> 00:03:05,000
+For example, you may the name of the product category, for example, doors and collections of all
+
+45
+00:03:05,000 --> 00:03:07,000
+doors associated with it.
+
+46
+00:03:07,000 --> 00:03:12,000
+You might have goods category and collection of booths associated with that key.
+
+47
+00:03:13,000 --> 00:03:19,000
+And in case you need to get all doors, you just make a request to the map button on the key to it to
+
+48
+00:03:19,000 --> 00:03:21,000
+retrieve all doors.
+
+49
+00:03:21,000 --> 00:03:22,000
+Does it make sense?
+
+50
+00:03:23,000 --> 00:03:29,000
+Maps are also considered a part of the collections framework because even if they don't have the same
+
+51
+00:03:29,000 --> 00:03:35,000
+interface as collections, they have operations that allow us to view and interact with them the same
+
+52
+00:03:35,000 --> 00:03:36,000
+way as with collections.
+
+53
+00:03:37,000 --> 00:03:43,000
+Implementation of MAP interfaces unions, of course, we are going to discuss different implementations
+
+54
+00:03:43,000 --> 00:03:48,000
+of the map and we are going to understand when we will use each implementation of the map interface.
+
+55
+00:03:49,000 --> 00:03:55,000
+Deprecated collections, deprecated collections are also part of the Java collections framework, despite
+
+56
+00:03:55,000 --> 00:04:00,000
+the fact that it is recommended not to use specific collections sometimes on the Java project.
+
+57
+00:04:00,000 --> 00:04:02,000
+You still going to work with them?
+
+58
+00:04:03,000 --> 00:04:09,000
+Because even nowadays there are a lot of old projects written on Java that require support and maintenance,
+
+59
+00:04:10,000 --> 00:04:11,000
+synchronized collections.
+
+60
+00:04:12,000 --> 00:04:17,000
+There are also special set of collections that are developed to be used in the multithreaded environment.
+
+61
+00:04:17,000 --> 00:04:19,000
+Let me tell you the example to make you understand.
+
+62
+00:04:20,000 --> 00:04:25,000
+Imagine that you have collections of users and one administrator of the website removes the user from
+
+63
+00:04:25,000 --> 00:04:31,000
+the collection and another administrator of the website is iterating over each user in the same collection
+
+64
+00:04:31,000 --> 00:04:33,000
+to update the state of the total.
+
+65
+00:04:33,000 --> 00:04:39,000
+Orders about the conflict might appear when two administrators in the two separate threats of execution
+
+66
+00:04:40,000 --> 00:04:41,000
+would obtain the same collection.
+
+67
+00:04:42,000 --> 00:04:47,000
+In this course, I'm going to tell you how centralized collections work and how to use them.
+
+68
+00:04:48,000 --> 00:04:50,000
+Algorithms also.
+
+69
+00:04:50,000 --> 00:04:56,000
+GCF includes algorithms that are the methods that perform useful computations, such as searching and
+
+70
+00:04:56,000 --> 00:05:03,000
+sorting on objects that implement collection interfaces that algorithms are said to be polymorphic.
+
+71
+00:05:03,000 --> 00:05:08,000
+That is, the same method can be used on many different implementations of the appropriate collection
+
+72
+00:05:08,000 --> 00:05:09,000
+interface.
+
+73
+00:05:10,000 --> 00:05:17,000
+Robbers GCF contains a special wrapper that can turn your regular collection into non modifiable collection
+
+74
+00:05:18,000 --> 00:05:23,000
+or wrapper, that can turn your regular collection into synchronized collection that you can use and
+
+75
+00:05:23,000 --> 00:05:24,000
+will just write an environment.
+
+76
+00:05:25,000 --> 00:05:31,000
+Now, when you know what a collection framework consists of, let's discuss what advantages does it
+
+77
+00:05:31,000 --> 00:05:32,000
+have over race?
+
+78
+00:05:33,000 --> 00:05:36,000
+Let's go over this table to compare collections and race.
+
+79
+00:05:37,000 --> 00:05:41,000
+This table will help you to understand what advantage collections have over race.
+
+80
+00:05:42,000 --> 00:05:48,000
+First of all, you already know that our racing driver have fixed size collections in Java can be extended
+
+81
+00:05:48,000 --> 00:05:49,000
+dynamically.
+
+82
+00:05:49,000 --> 00:05:54,000
+So using collections, there is no need to create new collection and copy the state of the previous
+
+83
+00:05:54,000 --> 00:05:59,000
+collection into the new one when you run out of space in this old collection.
+
+84
+00:05:59,000 --> 00:06:02,000
+There's a significant benefit for the development process.
+
+85
+00:06:03,000 --> 00:06:10,000
+Secondly, our race itself does not have any behavior and algorithms to work with them, for example,
+
+86
+00:06:10,000 --> 00:06:18,000
+a race can't filter themselves or find the first index of appearance of element or keep all elements
+
+87
+00:06:18,000 --> 00:06:25,000
+sorted automatically or have only unique elements and do not add elements that already exist in collection
+
+88
+00:06:25,000 --> 00:06:26,000
+and a lot of other things.
+
+89
+00:06:27,000 --> 00:06:33,000
+If you remember a race class, you may say that some of the algorithms are present in a race class to
+
+90
+00:06:33,000 --> 00:06:34,000
+work with the race.
+
+91
+00:06:34,000 --> 00:06:40,000
+But the amount of operations that you can do with our race class is significantly lower than a number
+
+92
+00:06:40,000 --> 00:06:43,000
+of algorithms that Java collections framework has.
+
+93
+00:06:43,000 --> 00:06:50,000
+And moreover, we mentioned separate class and static methods in a race class that is not the same as
+
+94
+00:06:50,000 --> 00:06:53,000
+behavior of the object like we have in collections.
+
+95
+00:06:54,000 --> 00:07:00,000
+Certainly collections have single API and no matter what is the specifics of each particular implementation
+
+96
+00:07:00,000 --> 00:07:06,000
+of the collection, whether it's stauss only unique elements or supports region of elements during the
+
+97
+00:07:06,000 --> 00:07:08,000
+constant amount of time, it doesn't matter.
+
+98
+00:07:09,000 --> 00:07:11,000
+All collections have common API.
+
+99
+00:07:11,000 --> 00:07:15,000
+What significantly simplifies usage of collections and running them.
+
+100
+00:07:16,000 --> 00:07:21,000
+On the other hand, working with arrays e.g. developer may implement his own application programming
+
+101
+00:07:21,000 --> 00:07:23,000
+interface to interact with a rate.
+
+102
+00:07:23,000 --> 00:07:29,000
+For example, the developer may come up with a method to add a new element in array and extend it in
+
+103
+00:07:29,000 --> 00:07:31,000
+case there is no more Plaisance.
+
+104
+00:07:31,000 --> 00:07:35,000
+Every developer may come up with a specific algorithm.
+
+105
+00:07:35,000 --> 00:07:37,000
+How to clear all elements in array.
+
+106
+00:07:37,000 --> 00:07:42,000
+One developer will just create a new array with the default array size and as a developer would just
+
+107
+00:07:42,000 --> 00:07:48,000
+turn into new values or current elements in array and the already might use a problem and such approach.
+
+108
+00:07:48,000 --> 00:07:52,000
+There is no single API when you are working with arrays.
+
+109
+00:07:53,000 --> 00:07:58,000
+By having such data structures and algorithms as collections, developers may concentrate on the important
+
+110
+00:07:58,000 --> 00:08:03,000
+parts of the program rather than on the low level work and inventions of your.
+
+111
+00:08:04,000 --> 00:08:10,000
+Forcedly, what you need to remember, collections can store only reference types of data collections
+
+112
+00:08:10,000 --> 00:08:12,000
+doesn't work with primitive types of data.
+
+113
+00:08:13,000 --> 00:08:17,000
+If you want to store primitive types of data because of the performance reasons, you still have to
+
+114
+00:08:17,000 --> 00:08:18,000
+use arrays.
+
+115
+00:08:19,000 --> 00:08:21,000
+And last but not the least performance.
+
+116
+00:08:22,000 --> 00:08:26,000
+Usually it is considered the performance of arrays is higher than performance of collections.
+
+117
+00:08:27,000 --> 00:08:32,000
+While this can be true in the modern world, in the most of business cases we are talking about milliseconds
+
+118
+00:08:32,000 --> 00:08:38,000
+difference for standard operations and for standard number of elements in either collection or array.
+
+119
+00:08:38,000 --> 00:08:44,000
+But you have to know about this and now you have the vision of what we are going to learn and what Java
+
+120
+00:08:44,000 --> 00:08:45,000
+collections framework is.
+
+121
+00:08:46,000 --> 00:08:49,000
+As you can see, there are really a lot of things to learn.
+
+122
+00:08:50,000 --> 00:08:52,000
+Right now, let's recap what we have learned today.
+
+123
+00:08:53,000 --> 00:08:57,000
+In this lesson, we learned what Java collections framework contains on the high level.
+
+124
+00:08:57,000 --> 00:09:03,000
+We understand what collections are and how they are different from maps during the last very of the
+
+125
+00:09:03,000 --> 00:09:09,000
+main advantages of collections of arrays and also discussed what advantages arrays have over collections.
+
+126
+00:09:10,000 --> 00:09:11,000
+That's all for now.
+
+127
+00:09:12,000 --> 00:09:15,000
+Thanks a lot for your attention and to you in the next lesson.
+

19 - Java Collections Framework/002 Collection Interface_en.srt

@@ -0,0 +1,596 @@
+1
+00:00:06,000 --> 00:00:06,000
+Hello.
+
+2
+00:00:06,000 --> 00:00:09,000
+Students, in this lesson, we are going to learn what connections are.
+
+3
+00:00:10,000 --> 00:00:15,000
+This is very important topic because connection interface is implemented by all connections implementations
+
+4
+00:00:15,000 --> 00:00:16,000
+in Java.
+
+5
+00:00:16,000 --> 00:00:23,000
+That's why understanding of collection interface is a key for understanding of all other collections
+
+6
+00:00:23,000 --> 00:00:23,000
+in Java.
+
+7
+00:00:24,000 --> 00:00:28,000
+So today our primary focus is learning of collection interface.
+
+8
+00:00:28,000 --> 00:00:35,000
+I'm going to show you your middle class diagram, will understand what it is and how we can use it in
+
+9
+00:00:35,000 --> 00:00:36,000
+the future.
+
+10
+00:00:36,000 --> 00:00:42,000
+To understand a type structure during the lesson will understand what methods collection interface has
+
+11
+00:00:42,000 --> 00:00:43,000
+and why do we need them.
+
+12
+00:00:44,000 --> 00:00:50,000
+We will review abstract and default methods of collection interface and at the end of the lesson, we'll
+
+13
+00:00:50,000 --> 00:00:52,000
+look at the collection source code.
+
+14
+00:00:52,000 --> 00:00:53,000
+Let's start.
+
+15
+00:00:53,000 --> 00:00:59,000
+I suggest that our lesson from this slide on this slide, you may see visualization of what the collection
+
+16
+00:00:59,000 --> 00:01:02,000
+is to understand collection.
+
+17
+00:01:02,000 --> 00:01:07,000
+Imagine the back, the big back where you may put all your stuff.
+
+18
+00:01:07,000 --> 00:01:15,000
+You might put your product, user card and all other objects, and you can retrieve exactly user or
+
+19
+00:01:15,000 --> 00:01:19,000
+product or cards by its index like you did in array.
+
+20
+00:01:20,000 --> 00:01:25,000
+What you can do is to put all things from your back on the floor and go over them one by one.
+
+21
+00:01:26,000 --> 00:01:31,000
+We're also going to learn in the separate lessons, the specific type that is developed to go over each
+
+22
+00:01:31,000 --> 00:01:32,000
+element.
+
+23
+00:01:32,000 --> 00:01:34,000
+What else we can do with these?
+
+24
+00:01:34,000 --> 00:01:40,000
+Back to answer this question, let's take a look at collection interface and we'll learn what else we
+
+25
+00:01:40,000 --> 00:01:42,000
+can do with our bag of elements.
+
+26
+00:01:43,000 --> 00:01:49,000
+Here is a class diagram we are going to learn with your UML language that is unified model and language
+
+27
+00:01:49,000 --> 00:01:50,000
+in detail a bit later.
+
+28
+00:01:51,000 --> 00:01:54,000
+But this is what is used to call class diagram.
+
+29
+00:01:54,000 --> 00:01:59,000
+And while being a software engineer, you are going to see such diagrams very often.
+
+30
+00:02:00,000 --> 00:02:01,000
+What do we have here?
+
+31
+00:02:01,000 --> 00:02:06,000
+We can see that collection interface extends a terrible interface, a terrible interface.
+
+32
+00:02:06,000 --> 00:02:10,000
+We are going to learn in a separate lesson, the same as Iterator.
+
+33
+00:02:10,000 --> 00:02:17,000
+But in short, this is an interface that stands on top of all collections interfaces to make sure that
+
+34
+00:02:17,000 --> 00:02:23,000
+it will be possible to iterate over each element in each implementation of collection interface.
+
+35
+00:02:24,000 --> 00:02:29,000
+Today we are going to focus on collection interface and we will start learning it from this class diagram.
+
+36
+00:02:30,000 --> 00:02:32,000
+Let me give you a quick introduction regarding symbols here.
+
+37
+00:02:33,000 --> 00:02:40,000
+You can find indication whether this type interface or no, that is our interface text right above the
+
+38
+00:02:40,000 --> 00:02:41,000
+interface name.
+
+39
+00:02:41,000 --> 00:02:46,000
+We can see that it's Arabel and collections, both interfaces here.
+
+40
+00:02:46,000 --> 00:02:52,000
+We can see list of methods that each specific type has, plus some means that this method is public.
+
+41
+00:02:53,000 --> 00:02:55,000
+After that goes method signature.
+
+42
+00:02:55,000 --> 00:02:59,000
+That is method, name and method parameters followed by colon.
+
+43
+00:02:59,000 --> 00:03:03,000
+And we can find return type right after the column.
+
+44
+00:03:03,000 --> 00:03:09,000
+For example, the first method in the list in collection interface is this method without parameters
+
+45
+00:03:09,000 --> 00:03:11,000
+that returns in value.
+
+46
+00:03:11,000 --> 00:03:12,000
+Does it make sense now?
+
+47
+00:03:13,000 --> 00:03:18,000
+This knowledge will help you to understand class diagrams written down on human language.
+
+48
+00:03:19,000 --> 00:03:21,000
+And let's answer our original question.
+
+49
+00:03:21,000 --> 00:03:23,000
+What else we can do with this back?
+
+50
+00:03:24,000 --> 00:03:26,000
+We can check a number of elements in it.
+
+51
+00:03:26,000 --> 00:03:28,000
+That is what size method does.
+
+52
+00:03:28,000 --> 00:03:31,000
+We can check if this bag is empty or no.
+
+53
+00:03:31,000 --> 00:03:34,000
+We can check if this bag is empty or no.
+
+54
+00:03:34,000 --> 00:03:41,000
+That's why when it is empty, we can ask our back elements, does it contain some specific element or
+
+55
+00:03:41,000 --> 00:03:45,000
+no contains measures that will help us with this task.
+
+56
+00:03:45,000 --> 00:03:51,000
+We have also matters that control collection of elements, interior objects and methods that can turn
+
+57
+00:03:51,000 --> 00:03:54,000
+collection of elements into the array of specific types.
+
+58
+00:03:54,000 --> 00:04:00,000
+For example, if your collection contains only elements of product type, we can convert our collection
+
+59
+00:04:00,000 --> 00:04:04,000
+into of product elements, but not in the array of objects.
+
+60
+00:04:04,000 --> 00:04:07,000
+If you don't want, can you feel the difference?
+
+61
+00:04:08,000 --> 00:04:08,000
+After that?
+
+62
+00:04:08,000 --> 00:04:11,000
+We can see methods that we already kind of discuss.
+
+63
+00:04:11,000 --> 00:04:12,000
+Let us add methods.
+
+64
+00:04:13,000 --> 00:04:15,000
+I can add elements to the collection.
+
+65
+00:04:15,000 --> 00:04:21,000
+I can also remove elements from the collection and to remove elements from the collection, I have to
+
+66
+00:04:21,000 --> 00:04:23,000
+pass this exact element.
+
+67
+00:04:24,000 --> 00:04:30,000
+Another important behavior, we can check whether this collection contains all elements that other collection
+
+68
+00:04:30,000 --> 00:04:30,000
+has.
+
+69
+00:04:30,000 --> 00:04:32,000
+That is our contains all method.
+
+70
+00:04:33,000 --> 00:04:36,000
+We can add all elements from one collection to another.
+
+71
+00:04:36,000 --> 00:04:43,000
+To do this, we have to use at all method and we can remove all elements from the current collections
+
+72
+00:04:43,000 --> 00:04:50,000
+and other collection has that is our remove all method and believe you can see on the slide that message
+
+73
+00:04:50,000 --> 00:04:51,000
+that we have just discussed.
+
+74
+00:04:51,000 --> 00:04:54,000
+Take out the collection as my argument.
+
+75
+00:04:54,000 --> 00:04:58,000
+If you want, you can keep only elements that are present in both collections.
+
+76
+00:04:58,000 --> 00:05:04,000
+To do this, we have to invoke retain all methods and positive reference to another collection into
+
+77
+00:05:04,000 --> 00:05:04,000
+it.
+
+78
+00:05:05,000 --> 00:05:11,000
+In other words, this message removes from the current collection all elements that are not present
+
+79
+00:05:11,000 --> 00:05:17,000
+in the collection that we passed as a method augment the methods that are left here are also describing
+
+80
+00:05:18,000 --> 00:05:23,000
+claims method will remove all elements from the collection and as you already know, equals and harsh
+
+81
+00:05:23,000 --> 00:05:26,000
+methods that are the methods that each object should have.
+
+82
+00:05:27,000 --> 00:05:33,000
+But the idea of specifying equals and Haskett methods in the collection interface is to put stress on
+
+83
+00:05:33,000 --> 00:05:39,000
+the fact that these methods should be implemented in an implementation of collection interface and that
+
+84
+00:05:39,000 --> 00:05:43,000
+these methods should override default behavior from object class.
+
+85
+00:05:43,000 --> 00:05:48,000
+And the last but not the least, massive collection interface is an iterator.
+
+86
+00:05:48,000 --> 00:05:51,000
+Pay attention to the iterable interface description now.
+
+87
+00:05:52,000 --> 00:05:57,000
+It is also the collection interface because it implements a terrible interface.
+
+88
+00:05:57,000 --> 00:06:03,000
+As you can see, Iterator method returns object of iterator type insert.
+
+89
+00:06:03,000 --> 00:06:07,000
+This object will help you to iterate over each element in your collection.
+
+90
+00:06:07,000 --> 00:06:13,000
+We are going to learn what Iterator is in the separate class and that is how our collection interface
+
+91
+00:06:13,000 --> 00:06:14,000
+that is something.
+
+92
+00:06:14,000 --> 00:06:15,000
+What do you have to remember?
+
+93
+00:06:16,000 --> 00:06:21,000
+We just have such interface and what we can do is just to remember it just as an alphabet.
+
+94
+00:06:21,000 --> 00:06:26,000
+We don't ask why a letter is written exactly in this way.
+
+95
+00:06:26,000 --> 00:06:30,000
+We just learned that this is a letter and how it sounds.
+
+96
+00:06:30,000 --> 00:06:36,000
+And when we know that we start building words with this letter, the same as here, we just have to
+
+97
+00:06:36,000 --> 00:06:38,000
+learn collection, interface and learn how to use it.
+
+98
+00:06:39,000 --> 00:06:45,000
+So here on the screen, you may see only abstract methods that should be implemented in each collection,
+
+99
+00:06:45,000 --> 00:06:49,000
+but there are a few more other default methods in the collection interface.
+
+100
+00:06:49,000 --> 00:06:55,000
+What are they to answer this question and to give you otherwise how constantly learn new things and
+
+101
+00:06:55,000 --> 00:07:00,000
+check information that you get not only on this lesson but in any tutorial?
+
+102
+00:07:00,000 --> 00:07:03,000
+Always investigate the source code of your conversion.
+
+103
+00:07:04,000 --> 00:07:09,000
+I believe you remember how to add source code, your code editor and where you might find it.
+
+104
+00:07:09,000 --> 00:07:14,000
+Let's open collection type to investigate the source code and find methods that we didn't learn yet.
+
+105
+00:07:15,000 --> 00:07:20,000
+I press control shift and simultaneously I have to type collection.
+
+106
+00:07:21,000 --> 00:07:27,000
+I need collection from Java with your package and here this and here on the right, we might see a list
+
+107
+00:07:27,000 --> 00:07:30,000
+of all methods that are present in this interface.
+
+108
+00:07:30,000 --> 00:07:34,000
+It looks like we went over all abstract methods.
+
+109
+00:07:34,000 --> 00:07:40,000
+How I learned which method is abstract and it's is a small a letter that stands for abstract.
+
+110
+00:07:41,000 --> 00:07:45,000
+But we didn't cover in our presentation methods that have Glitnir.
+
+111
+00:07:45,000 --> 00:07:46,000
+What are they?
+
+112
+00:07:47,000 --> 00:07:50,000
+Here's the overloaded method to array it.
+
+113
+00:07:50,000 --> 00:07:57,000
+Just take specific functions that will describe how to convert collection to a right to be able to apply
+
+114
+00:07:57,000 --> 00:07:57,000
+this method.
+
+115
+00:07:57,000 --> 00:08:03,000
+We have to know how to write in the functional style in Java and understand what functional interface
+
+116
+00:08:03,000 --> 00:08:03,000
+is.
+
+117
+00:08:04,000 --> 00:08:05,000
+Don't worry.
+
+118
+00:08:05,000 --> 00:08:08,000
+This topic also will be discussed in the separate lesson.
+
+119
+00:08:08,000 --> 00:08:13,000
+I just want you to understand, at least on the high level, what these default methods are about.
+
+120
+00:08:13,000 --> 00:08:21,000
+Remove method, this method takes predicate, predicate is a specific type that can return true or false
+
+121
+00:08:22,000 --> 00:08:26,000
+based on the specific function that you will pass as a method argument to this method.
+
+122
+00:08:26,000 --> 00:08:29,000
+It will identify which element should be removed.
+
+123
+00:08:29,000 --> 00:08:32,000
+For example, you may describe functions that will return.
+
+124
+00:08:32,000 --> 00:08:38,000
+True in a case product price is more than one hundred dollars, and in case this function will be applied
+
+125
+00:08:38,000 --> 00:08:44,000
+to this specific product and collection, it will be removed and this function will be applied to each
+
+126
+00:08:44,000 --> 00:08:50,000
+element in the collection you might find while loop here and see that Iterator is used to go over the
+
+127
+00:08:50,000 --> 00:08:56,000
+collection as a condition for each element in the collection and remove it in case it satisfies the
+
+128
+00:08:56,000 --> 00:08:57,000
+condition.
+
+129
+00:08:57,000 --> 00:09:01,000
+Also, there is a default method that creates iterator.
+
+130
+00:09:01,000 --> 00:09:07,000
+Split Iterator is a specific type that can traverse and make parts of elements of the source collection.
+
+131
+00:09:08,000 --> 00:09:11,000
+And here is a method that exists in all implementations of collection.
+
+132
+00:09:11,000 --> 00:09:18,000
+Interface Stream Method joins the collection into stream of elements or in other words, sequential
+
+133
+00:09:18,000 --> 00:09:19,000
+stream of elements.
+
+134
+00:09:20,000 --> 00:09:26,000
+String Mapei was introduced in Java version eight and it was a breakthrough in this course in separate
+
+135
+00:09:26,000 --> 00:09:31,000
+lesson will be on stream API and we'll learn how to use it as a practical exercise.
+
+136
+00:09:31,000 --> 00:09:35,000
+Will even rewrite our home tasks with the help of the Stream API.
+
+137
+00:09:36,000 --> 00:09:38,000
+And here is a massive, transparent stream.
+
+138
+00:09:39,000 --> 00:09:44,000
+According to documentation, it returns possible parallel stream with the current collection at its
+
+139
+00:09:44,000 --> 00:09:44,000
+source.
+
+140
+00:09:46,000 --> 00:09:51,000
+Now, let's recap what we have learned today, so they've learned what the connection is, we try to
+
+141
+00:09:51,000 --> 00:09:54,000
+imagine collection is a back for our understanding.
+
+142
+00:09:55,000 --> 00:09:59,000
+The day you saw your first UML diagram, class diagram.
+
+143
+00:09:59,000 --> 00:10:05,000
+Now you know how to read class diagrams to understand the type of description we reviewed all abstract
+
+144
+00:10:05,000 --> 00:10:07,000
+methods in collection interface.
+
+145
+00:10:07,000 --> 00:10:10,000
+And after that, we reviewed the collection before methods.
+
+146
+00:10:10,000 --> 00:10:14,000
+Also during the lesson we investigated source code of collection interface.
+
+147
+00:10:15,000 --> 00:10:17,000
+That's all what I have for you for today.
+
+148
+00:10:17,000 --> 00:10:18,000
+Thanks a lot for your attention.
+
+149
+00:10:18,000 --> 00:10:20,000
+See you in the next lesson.
+

19 - Java Collections Framework/003 Interfaces List, Set and Queue Overview_en.srt

@@ -0,0 +1,472 @@
+1
+00:00:06,000 --> 00:00:06,000
+Hello, Jim.
+
+2
+00:00:06,000 --> 00:00:12,000
+In this lesson, I'll go to understand the main descendants of collection interface before going deep,
+
+3
+00:00:12,000 --> 00:00:18,000
+I believe it is very important to understand the big picture and learn three main interfaces in collections.
+
+4
+00:00:18,000 --> 00:00:23,000
+Iraqi today will hold a high level overview of such interfaces likely set.
+
+5
+00:00:23,000 --> 00:00:29,000
+And Q According to our agenda, we are going to start from the overview of the class diagram of collection
+
+6
+00:00:29,000 --> 00:00:32,000
+interface with its main descendants.
+
+7
+00:00:32,000 --> 00:00:37,000
+After that, I'm going to explain in simple words what a key difference is between three interfaces
+
+8
+00:00:37,000 --> 00:00:38,000
+and why we need them.
+
+9
+00:00:39,000 --> 00:00:44,000
+I will explain you what list is said and Q You use the explanation of the cube.
+
+10
+00:00:44,000 --> 00:00:48,000
+We are going to learn what f i f o principle is.
+
+11
+00:00:48,000 --> 00:00:54,000
+This lesson will help you to understand the first structure of our lessons and understand the core hierarchy
+
+12
+00:00:54,000 --> 00:00:55,000
+of collections.
+
+13
+00:00:55,000 --> 00:00:58,000
+Let's start here is our class diagram.
+
+14
+00:00:59,000 --> 00:01:02,000
+This one is the extended version of the one you saw in the previous lesson.
+
+15
+00:01:03,000 --> 00:01:06,000
+I believe you are already familiar with the collection interface.
+
+16
+00:01:06,000 --> 00:01:12,000
+Now let's look at the most popular child interfaces of collection interface that we are going to learn.
+
+17
+00:01:12,000 --> 00:01:18,000
+There are three interfaces that extends collection interface and that implemented by all the collection
+
+18
+00:01:18,000 --> 00:01:25,000
+implementations in GDP, Zaya least set and Q They're all collections.
+
+19
+00:01:25,000 --> 00:01:32,000
+But each interface is introduced in behavior on the quality of implementation of collection interface
+
+20
+00:01:32,000 --> 00:01:33,000
+by extending it.
+
+21
+00:01:33,000 --> 00:01:35,000
+Why do we need this interfaces?
+
+22
+00:01:36,000 --> 00:01:38,000
+Let me briefly go over each one.
+
+23
+00:01:39,000 --> 00:01:40,000
+Let's start from the least interface.
+
+24
+00:01:41,000 --> 00:01:45,000
+You already know that collection is just a back where you can put all your elements.
+
+25
+00:01:46,000 --> 00:01:47,000
+The list interface.
+
+26
+00:01:47,000 --> 00:01:52,000
+Introduce an ordered collection with the possibility to manage your elements by the index.
+
+27
+00:01:53,000 --> 00:01:56,000
+In the more simple words list is an order.
+
+28
+00:01:56,000 --> 00:01:58,000
+A collection of elements was all benefit.
+
+29
+00:01:58,000 --> 00:02:00,000
+That follows from that statement.
+
+30
+00:02:01,000 --> 00:02:04,000
+We can add element to the specific index and the collection.
+
+31
+00:02:04,000 --> 00:02:11,000
+We can get element by its index and we can replace existing element as a specific position to set the
+
+32
+00:02:11,000 --> 00:02:14,000
+new element in the specific position we have to use, said Mass.
+
+33
+00:02:15,000 --> 00:02:17,000
+With a specific index and element.
+
+34
+00:02:18,000 --> 00:02:22,000
+If we want, we can remove the element from the specific position in our list.
+
+35
+00:02:22,000 --> 00:02:28,000
+We can get the index of the first occurrence of the element in the specific collection and index of
+
+36
+00:02:28,000 --> 00:02:32,000
+the last occurrence of the specific element to perform these tasks.
+
+37
+00:02:32,000 --> 00:02:41,000
+Mass index of and last index should help us at least also allows us to get list iterator list iterator
+
+38
+00:02:41,000 --> 00:02:46,000
+that this extended version of the regular iterator in the separate class in about iterators.
+
+39
+00:02:46,000 --> 00:02:47,000
+And we'll explain the difference.
+
+40
+00:02:48,000 --> 00:02:54,000
+Sometimes we may want to create some lists, for example, to process back amount of data.
+
+41
+00:02:54,000 --> 00:03:00,000
+We may split our list into four equal chunks and perform any operations we need in four separate sets
+
+42
+00:03:00,000 --> 00:03:01,000
+of execution.
+
+43
+00:03:02,000 --> 00:03:07,000
+I believe you are aware that Java supports MultiThreaded and a bit later in the course, I'm also going
+
+44
+00:03:07,000 --> 00:03:08,000
+to teach you that.
+
+45
+00:03:09,000 --> 00:03:14,000
+Besides new absurd methods that were introduced, there are also to default matters that are absent
+
+46
+00:03:14,000 --> 00:03:17,000
+in connection interface and that are present in the list interface.
+
+47
+00:03:18,000 --> 00:03:20,000
+Zaya, replace all MassArt.
+
+48
+00:03:20,000 --> 00:03:26,000
+This method will take a function that can transform an element of one type to the element of the same
+
+49
+00:03:26,000 --> 00:03:26,000
+type.
+
+50
+00:03:27,000 --> 00:03:32,000
+We may want to use this method when we want, for example, transform all string objects in the list
+
+51
+00:03:32,000 --> 00:03:35,000
+to the string objects in the lowercase.
+
+52
+00:03:36,000 --> 00:03:42,000
+Sort method allows us to set the algorithm and to tell exactly how we want to certain elements in the
+
+53
+00:03:42,000 --> 00:03:47,000
+list, a bit later we're going to run such a functional interface as comparator.
+
+54
+00:03:48,000 --> 00:03:50,000
+Now, let's proceed with the collections Iraqi.
+
+55
+00:03:50,000 --> 00:03:52,000
+Let's talk about set interface.
+
+56
+00:03:53,000 --> 00:03:54,000
+What do you think?
+
+57
+00:03:54,000 --> 00:03:59,000
+What new methods are introduced in the set interface in comparison with collection interface?
+
+58
+00:04:00,000 --> 00:04:04,000
+No one is a set interface, doesn't introduce new methods.
+
+59
+00:04:05,000 --> 00:04:06,000
+Then why do we need it at all?
+
+60
+00:04:07,000 --> 00:04:10,000
+Let's recall what a set is from the mathematics.
+
+61
+00:04:10,000 --> 00:04:13,000
+The set is a well defined collection of discrete.
+
+62
+00:04:14,000 --> 00:04:17,000
+The set is a well defined collection of distinct objects.
+
+63
+00:04:18,000 --> 00:04:22,000
+The set interface is a main interface for the Iraqi of containers.
+
+64
+00:04:22,000 --> 00:04:25,000
+By the way, collections are often called containers.
+
+65
+00:04:26,000 --> 00:04:33,000
+So set is the main interface for the hierarchy of containers that contains only unique elements that
+
+66
+00:04:33,000 --> 00:04:40,000
+different implementations of the set interface during the development of JDK engineers come up with
+
+67
+00:04:40,000 --> 00:04:45,000
+the decisions that they need to distinguish a collection of elements and the set of elements.
+
+68
+00:04:45,000 --> 00:04:49,000
+Somehow the best decision was to introduce new interface.
+
+69
+00:04:49,000 --> 00:04:51,000
+So you're of development.
+
+70
+00:04:51,000 --> 00:04:57,000
+Engineers may declare variable of type set that would give us new methods to manipulate with elements
+
+71
+00:04:57,000 --> 00:04:58,000
+in the container.
+
+72
+00:04:59,000 --> 00:05:04,000
+But this instantly will give us the vision that this container contains only unique elements.
+
+73
+00:05:05,000 --> 00:05:10,000
+To understand how implementations of the set interface work, we need to learn map interfaces first.
+
+74
+00:05:11,000 --> 00:05:13,000
+We are going to understand later why.
+
+75
+00:05:14,000 --> 00:05:18,000
+And now let's review one more interface Hirschi interface.
+
+76
+00:05:18,000 --> 00:05:22,000
+There are a few new abstract methods were introduced here to manage the queue.
+
+77
+00:05:23,000 --> 00:05:31,000
+They are offer to insert an element into the queue, remove this method to retrieve and remove the head
+
+78
+00:05:31,000 --> 00:05:32,000
+of the queue.
+
+79
+00:05:32,000 --> 00:05:36,000
+But in case there is an empty queue, the method throws exception.
+
+80
+00:05:36,000 --> 00:05:37,000
+What is an exception?
+
+81
+00:05:38,000 --> 00:05:43,000
+And a bit later we are going to learn how Java programs may handle exceptional situations of program
+
+82
+00:05:43,000 --> 00:05:44,000
+execution.
+
+83
+00:05:44,000 --> 00:05:50,000
+Right now you can understand exception like something what is not an expected way of program execution
+
+84
+00:05:50,000 --> 00:05:56,000
+and what may potentially interrupt the program in case there is no code written that handles the exception
+
+85
+00:05:57,000 --> 00:06:03,000
+for this method also retrieves and removes the head of the queue the same as remove method, but with
+
+86
+00:06:03,000 --> 00:06:09,000
+only one difference in case queue is empty, there is no exception, no value is returned instead.
+
+87
+00:06:10,000 --> 00:06:17,000
+Element this MassArt retrieves but doesn't remove elements from the Q the same as remove method, it
+
+88
+00:06:17,000 --> 00:06:19,000
+throws exception in the case.
+
+89
+00:06:19,000 --> 00:06:19,000
+Q is empty.
+
+90
+00:06:20,000 --> 00:06:27,000
+Take Macit also retrieved but doesn't remove elements from the cube, with only one exception, that
+
+91
+00:06:27,000 --> 00:06:30,000
+in case there is an empty cube, no value is returned.
+
+92
+00:06:31,000 --> 00:06:36,000
+That's all new methods that were introduced in Q interface, no other default methods were introduced,
+
+93
+00:06:37,000 --> 00:06:44,000
+cues needed when you need to implement first in, first out principle, so-called f i f o principle,
+
+94
+00:06:45,000 --> 00:06:51,000
+imagine that you process support requests and you need to process them in the specific priority.
+
+95
+00:06:51,000 --> 00:06:57,000
+And according to the date, when you receive them the support you get that you received the earliest.
+
+96
+00:06:58,000 --> 00:06:58,000
+Exactly.
+
+97
+00:06:58,000 --> 00:07:01,000
+These tickets should be processed first.
+
+98
+00:07:02,000 --> 00:07:04,000
+And here you can understand what the queue is.
+
+99
+00:07:05,000 --> 00:07:11,000
+The first support that was received by Q The first left in the queue.
+
+100
+00:07:11,000 --> 00:07:12,000
+I feel really prepared.
+
+101
+00:07:12,000 --> 00:07:18,000
+Super interesting home task for you to improve our online store and to practice your skills in writing
+
+102
+00:07:18,000 --> 00:07:20,000
+use, but that will be later.
+
+103
+00:07:21,000 --> 00:07:27,000
+So right now I believe you understood the three main sub Iraqis that goes right after collection interface.
+
+104
+00:07:27,000 --> 00:07:33,000
+And also the structure of the next lesson should be clearer for you now during the next lesson.
+
+105
+00:07:33,000 --> 00:07:39,000
+So we are going to learn each interface in detail with all methods and to learn the most popular implementation
+
+106
+00:07:39,000 --> 00:07:40,000
+of each interface.
+
+107
+00:07:41,000 --> 00:07:44,000
+I want you to understand, Siiri, first before we start calling.
+
+108
+00:07:44,000 --> 00:07:46,000
+Believe me, this is very important.
+
+109
+00:07:47,000 --> 00:07:51,000
+But very soon you would beg me to stop quoting examples, I promise you.
+
+110
+00:07:52,000 --> 00:07:54,000
+Now, let's review what we have learned today.
+
+111
+00:07:55,000 --> 00:07:58,000
+Today we have learned what has remained descendants of collection interface.
+
+112
+00:07:59,000 --> 00:08:03,000
+Now you know why we need at least set new interfaces.
+
+113
+00:08:03,000 --> 00:08:09,000
+Moreover, after this lesson, you may understand the difference between them while explaining what
+
+114
+00:08:09,000 --> 00:08:09,000
+A is.
+
+115
+00:08:09,000 --> 00:08:12,000
+We learned f o principle.
+
+116
+00:08:12,000 --> 00:08:14,000
+Now you are ready for the next lesson.
+
+117
+00:08:15,000 --> 00:08:16,000
+Thanks a lot for your attention.
+
+118
+00:08:16,000 --> 00:08:18,000
+See you in the next lesson.
+

19 - Java Collections Framework/004 List implementations - ArrayList, Vector, CopyOnWriteArrayList & Stack_en.srt

@@ -0,0 +1,1152 @@
+1
+00:00:06,000 --> 00:00:06,000
+Hello.
+
+2
+00:00:06,000 --> 00:00:11,000
+Yes, students, today we are going to talk about implementations of the list interface, we are going
+
+3
+00:00:11,000 --> 00:00:17,000
+to discuss such implementations as our list vector question right away, list and stack.
+
+4
+00:00:17,000 --> 00:00:23,000
+You have a lot of things to learn in this lesson besides the learning of the specific classes.
+
+5
+00:00:23,000 --> 00:00:28,000
+We are going to answer the question when you have to use each particular implementation of list interface.
+
+6
+00:00:28,000 --> 00:00:34,000
+I'm going to share with you real life examples where we will use list implementations today during the
+
+7
+00:00:34,000 --> 00:00:39,000
+lesson I'm going to show you is a tool that will allow you to investigate the interaction of classes
+
+8
+00:00:39,000 --> 00:00:40,000
+in the clips.
+
+9
+00:00:40,000 --> 00:00:45,000
+During the lesson, we are going to compare different implementations of the list interface so that
+
+10
+00:00:45,000 --> 00:00:50,000
+you could understand what pros and cons of each implementations are in this lesson.
+
+11
+00:00:50,000 --> 00:00:56,000
+We are going to compare on the array vector Copan right away and Stack also.
+
+12
+00:00:56,000 --> 00:01:01,000
+We're going to learn what mocker interfaces are and what is random access interface.
+
+13
+00:01:01,000 --> 00:01:04,000
+So as you can see, we have a huge agenda for today.
+
+14
+00:01:05,000 --> 00:01:07,000
+Let's don't waste our time and start our lesson.
+
+15
+00:01:08,000 --> 00:01:09,000
+Brunious lessons.
+
+16
+00:01:09,000 --> 00:01:14,000
+You already learned what list is, but let's try to answer the question when we have to use list.
+
+17
+00:01:15,000 --> 00:01:20,000
+In my opinion, list implementations can cover the requirements of the widest range of business cases.
+
+18
+00:01:21,000 --> 00:01:21,000
+Why?
+
+19
+00:01:22,000 --> 00:01:23,000
+Because of the next reasons.
+
+20
+00:01:24,000 --> 00:01:26,000
+Support of data manipulation by Elements Index.
+
+21
+00:01:27,000 --> 00:01:33,000
+You may want to retrieve product from specific index in your list of products, or you may want to put
+
+22
+00:01:33,000 --> 00:01:36,000
+user in the list of users in the middle of the list by its index.
+
+23
+00:01:37,000 --> 00:01:42,000
+Or probably you always want to add the new user since the beginning of the list, but not at the end.
+
+24
+00:01:42,000 --> 00:01:48,000
+The possibility to use index to manage element positions gives you a lot of options for data manipulations
+
+25
+00:01:48,000 --> 00:01:50,000
+that will help you in different business cases.
+
+26
+00:01:51,000 --> 00:01:55,000
+And another reason list implementations may contain duplicates.
+
+27
+00:01:55,000 --> 00:02:01,000
+Sometimes you just need to have container that will store all your products, for example, and you
+
+28
+00:02:01,000 --> 00:02:03,000
+don't care about duplicate there.
+
+29
+00:02:03,000 --> 00:02:07,000
+You just need to have a list of all products here.
+
+30
+00:02:08,000 --> 00:02:14,000
+That's why, which is at least overset sometimes one more reason usability to create subleased.
+
+31
+00:02:14,000 --> 00:02:16,000
+This feature is really attractive.
+
+32
+00:02:16,000 --> 00:02:18,000
+One for some specific business cases.
+
+33
+00:02:18,000 --> 00:02:21,000
+Let me share with you one example from the real life.
+
+34
+00:02:21,000 --> 00:02:25,000
+We implemented mobile app for the betting tips in this app.
+
+35
+00:02:25,000 --> 00:02:27,000
+We received data from the server.
+
+36
+00:02:27,000 --> 00:02:29,000
+We store the data in the list.
+
+37
+00:02:30,000 --> 00:02:33,000
+There was such the main type asport prediction data.
+
+38
+00:02:33,000 --> 00:02:39,000
+eSport prediction was done for the specific sports event that may happen either today or yesterday or
+
+39
+00:02:39,000 --> 00:02:40,000
+tomorrow.
+
+40
+00:02:40,000 --> 00:02:46,000
+So developers created sub lists of the sport prediction for yesterday, today and tomorrow.
+
+41
+00:02:46,000 --> 00:02:50,000
+We created three lists instead of one by splitting the original one.
+
+42
+00:02:51,000 --> 00:02:57,000
+Why we could pass the one list to each widget to draw the list on the UI interface only for specific
+
+43
+00:02:57,000 --> 00:02:58,000
+date.
+
+44
+00:02:58,000 --> 00:03:00,000
+That's it, by the way.
+
+45
+00:03:00,000 --> 00:03:03,000
+Here is the UI of the sports app, Anderson.
+
+46
+00:03:04,000 --> 00:03:07,000
+You will be able to create similar apps, so don't worry.
+
+47
+00:03:07,000 --> 00:03:12,000
+To implement such application, you have to know implementations of the list interface.
+
+48
+00:03:12,000 --> 00:03:15,000
+Let's move further certain.
+
+49
+00:03:15,000 --> 00:03:19,000
+And again, one more features a collection interface doesn't have.
+
+50
+00:03:19,000 --> 00:03:25,000
+We may sort our button Tepes based on the level of probability that really improves interaction with
+
+51
+00:03:25,000 --> 00:03:26,000
+the app.
+
+52
+00:03:26,000 --> 00:03:29,000
+Moreover, I can offer user to source support.
+
+53
+00:03:29,000 --> 00:03:37,000
+Prediction is a high probability score or by keep also rating or by anything else, wide range of use.
+
+54
+00:03:37,000 --> 00:03:43,000
+And one more important reason to opt for these implementations, and this reason probably is the most
+
+55
+00:03:43,000 --> 00:03:46,000
+important one that is not written in any book that you read.
+
+56
+00:03:46,000 --> 00:03:52,000
+Engineers use list implementations and most of the times because they just don't use a set.
+
+57
+00:03:52,000 --> 00:03:59,000
+Documentation's developers just need some container to store multiple elements in there and treat them
+
+58
+00:03:59,000 --> 00:04:02,000
+as a single unit without any extra features.
+
+59
+00:04:02,000 --> 00:04:07,000
+OK, now we want to know when and why we opt for liste implementations.
+
+60
+00:04:07,000 --> 00:04:13,000
+Let's investigate list Iraqi on this slide you may use at least the interface is implemented by absoluteness
+
+61
+00:04:13,000 --> 00:04:14,000
+class.
+
+62
+00:04:14,000 --> 00:04:15,000
+Absolutely.
+
+63
+00:04:15,000 --> 00:04:20,000
+Tintern extends APSA collection and is extended by Absol sequential sequentially.
+
+64
+00:04:21,000 --> 00:04:27,000
+From this diagram you may see that our own list is extended directly from the absolute list, the same
+
+65
+00:04:27,000 --> 00:04:33,000
+as vector and copy and write and released and linked list is extended from absolute sequential list
+
+66
+00:04:33,000 --> 00:04:37,000
+stack class extends vector engineers.
+
+67
+00:04:37,000 --> 00:04:41,000
+Doesn't like Stack for that because that is not the least by its essence.
+
+68
+00:04:42,000 --> 00:04:43,000
+It is closer to the reverse.
+
+69
+00:04:43,000 --> 00:04:45,000
+CU does a deck interface.
+
+70
+00:04:46,000 --> 00:04:52,000
+We're going to run it later, but because of the backward compatibility creator subject didn't change
+
+71
+00:04:52,000 --> 00:04:53,000
+anything here.
+
+72
+00:04:54,000 --> 00:04:54,000
+Is it clear?
+
+73
+00:04:55,000 --> 00:05:02,000
+Because Stack in its essence implement last in, first out principle, but it extends least interface,
+
+74
+00:05:02,000 --> 00:05:02,000
+but not that.
+
+75
+00:05:03,000 --> 00:05:09,000
+Even despite this, glass will not be used very often by a during the development, you might be asked
+
+76
+00:05:09,000 --> 00:05:11,000
+about it during the interview.
+
+77
+00:05:11,000 --> 00:05:13,000
+That's why I decided to mention it here.
+
+78
+00:05:14,000 --> 00:05:19,000
+What is also worth to mention is the implementation of random access interface.
+
+79
+00:05:19,000 --> 00:05:25,000
+Today during the demo, I'm going to show you what random access interface is and what mocker interfaces
+
+80
+00:05:25,000 --> 00:05:31,000
+are to protect our lesson today as I just jump into the eclipse to investigate the source code that
+
+81
+00:05:31,000 --> 00:05:35,000
+will help us to learn the topic better understand them.
+
+82
+00:05:35,000 --> 00:05:39,000
+I'd like to share with you the trick that will also help you in the future during the development.
+
+83
+00:05:39,000 --> 00:05:45,000
+Namely, I'd like to show you how you can easily find implementations of each interface and reviews
+
+84
+00:05:45,000 --> 00:05:48,000
+a whole Iraqian, for example.
+
+85
+00:05:48,000 --> 00:05:50,000
+Here is a list interface.
+
+86
+00:05:50,000 --> 00:05:54,000
+I should put the cursor into the editor error and press efore button.
+
+87
+00:05:55,000 --> 00:05:57,000
+Or you can also make mouse right.
+
+88
+00:05:57,000 --> 00:06:02,000
+Click and select open type Iraqi here and we can see that the separate widget is open.
+
+89
+00:06:02,000 --> 00:06:07,000
+Here, here I see items that extends or implements the interface.
+
+90
+00:06:07,000 --> 00:06:09,000
+For example, here's our list.
+
+91
+00:06:10,000 --> 00:06:16,000
+We can make a left mouse click to open it and here we may find our array list.
+
+92
+00:06:16,000 --> 00:06:20,000
+As you can see, there are really a lot of classes over here will not run.
+
+93
+00:06:20,000 --> 00:06:25,000
+Each of them instead will focus only on those that you will use during your work.
+
+94
+00:06:26,000 --> 00:06:32,000
+Let's start from the most popular implementation of this interface that you will use in 98 percent of
+
+95
+00:06:32,000 --> 00:06:32,000
+cases.
+
+96
+00:06:33,000 --> 00:06:34,000
+That is just my assumption.
+
+97
+00:06:34,000 --> 00:06:42,000
+But you will tell me that if I was right, here's a release class when people are released because it's
+
+98
+00:06:42,000 --> 00:06:47,000
+really fast and most simple words released is array with dynamic size.
+
+99
+00:06:48,000 --> 00:06:50,000
+But this is in very, very simple words.
+
+100
+00:06:51,000 --> 00:06:55,000
+I only use regular arrays inside to store elements here.
+
+101
+00:06:55,000 --> 00:07:00,000
+This is a variable is called element data in my store array of objects.
+
+102
+00:07:00,000 --> 00:07:07,000
+That means that technically we can put everything in this array, but we can't because this field has
+
+103
+00:07:07,000 --> 00:07:09,000
+packaged private modifier.
+
+104
+00:07:09,000 --> 00:07:15,000
+OK, then you might be wondering if I only use this regular array to store elements, then it should
+
+105
+00:07:15,000 --> 00:07:18,000
+have fixed size, is that correct?
+
+106
+00:07:18,000 --> 00:07:19,000
+That is correct.
+
+107
+00:07:20,000 --> 00:07:23,000
+Arrays in Java have fixed size, but not the array.
+
+108
+00:07:23,000 --> 00:07:27,000
+Least let me show is a code that adds element to the collection.
+
+109
+00:07:28,000 --> 00:07:33,000
+Here is an element method in today's modification count variable first.
+
+110
+00:07:33,000 --> 00:07:35,000
+Don't pay attention to that right now.
+
+111
+00:07:35,000 --> 00:07:38,000
+After that it calls another add method.
+
+112
+00:07:38,000 --> 00:07:41,000
+I hold control key and press mouse left click.
+
+113
+00:07:41,000 --> 00:07:50,000
+OK, here is a private matter and you see the first line we have if statement here we check if s equals
+
+114
+00:07:50,000 --> 00:07:55,000
+to the length of the array, then we initialize our element data array with the new array.
+
+115
+00:07:56,000 --> 00:08:00,000
+Before we go further, let's look what this s variable is.
+
+116
+00:08:00,000 --> 00:08:06,000
+I hold all key and press our left key to move back to the previous position where I was.
+
+117
+00:08:06,000 --> 00:08:13,000
+And we see that the argument in this method is a size variable size is also one of the fields in a release
+
+118
+00:08:13,000 --> 00:08:14,000
+class.
+
+119
+00:08:14,000 --> 00:08:15,000
+Now let's get back.
+
+120
+00:08:16,000 --> 00:08:22,000
+I keep all key press and also press arrow right key to get back to the place in the source code where
+
+121
+00:08:22,000 --> 00:08:23,000
+I was before.
+
+122
+00:08:23,000 --> 00:08:26,000
+Now, you know, that s is a size.
+
+123
+00:08:27,000 --> 00:08:28,000
+What does Groom method do?
+
+124
+00:08:29,000 --> 00:08:30,000
+Let me answer that question.
+
+125
+00:08:31,000 --> 00:08:32,000
+OK.
+
+126
+00:08:32,000 --> 00:08:37,000
+This method calls another group method within argument and person size plus one there.
+
+127
+00:08:38,000 --> 00:08:39,000
+And what do we have here?
+
+128
+00:08:40,000 --> 00:08:46,000
+We see that in arguments that we passed to this method is used to define desired minimum capacity.
+
+129
+00:08:47,000 --> 00:08:54,000
+You may see has that old capacity is equal to arrest lengths and in case old capacity is more than zero.
+
+130
+00:08:54,000 --> 00:08:57,000
+We calculate new capacity, how it is calculated.
+
+131
+00:08:57,000 --> 00:09:02,000
+I suggest you to investigate by itself by going deeper and method and location change.
+
+132
+00:09:03,000 --> 00:09:05,000
+By the way, you might see here bitwise shift.
+
+133
+00:09:06,000 --> 00:09:09,000
+And it is great that by this lesson you already know how it works.
+
+134
+00:09:10,000 --> 00:09:15,000
+If you don't know, please review my lesson from the Java course about operators.
+
+135
+00:09:15,000 --> 00:09:23,000
+And after that we use a race class to copy our current theory to the one with the new capacity and we
+
+136
+00:09:23,000 --> 00:09:24,000
+return the reference to this array.
+
+137
+00:09:25,000 --> 00:09:31,000
+So now you can understand that when there is no space for new element Ansary, the values from the old
+
+138
+00:09:31,000 --> 00:09:34,000
+are a cockpit to the new array was the new size.
+
+139
+00:09:35,000 --> 00:09:40,000
+OK, but what happens if we have just created the of our type and it's empty?
+
+140
+00:09:41,000 --> 00:09:43,000
+Let's check the default constructor.
+
+141
+00:09:44,000 --> 00:09:47,000
+We can see that element data is initialized with the empty array.
+
+142
+00:09:48,000 --> 00:09:50,000
+This is constant empty array.
+
+143
+00:09:50,000 --> 00:09:53,000
+But why do we need this default capacity constant?
+
+144
+00:09:54,000 --> 00:09:57,000
+To answer this, let's get back to zero method.
+
+145
+00:09:57,000 --> 00:09:59,000
+Pay attention to the if clause here.
+
+146
+00:10:00,000 --> 00:10:02,000
+If old capacity more than zero.
+
+147
+00:10:02,000 --> 00:10:06,000
+And we know that when our only has been just created, its size is zero.
+
+148
+00:10:07,000 --> 00:10:12,000
+And the second clause is if Elliman data is not equal to the full capacity MHRA.
+
+149
+00:10:12,000 --> 00:10:17,000
+We know that this statement is also false because we initialized our rate with this constant.
+
+150
+00:10:18,000 --> 00:10:25,000
+So that's why our full program execution goes to the else block where we initialize our element data
+
+151
+00:10:25,000 --> 00:10:32,000
+array with the rate of the Langston Wighton because it will take Maximilien between ten and one during
+
+152
+00:10:32,000 --> 00:10:33,000
+the creation of three.
+
+153
+00:10:34,000 --> 00:10:37,000
+Does it make sense now as a part of your homework?
+
+154
+00:10:37,000 --> 00:10:43,000
+I would encourage you to go over each method in a release like we did with Add Method to understand
+
+155
+00:10:43,000 --> 00:10:46,000
+how Array Works program.
+
+156
+00:10:46,000 --> 00:10:50,000
+You might be wondered whether you can create an array list with a specific capacity.
+
+157
+00:10:51,000 --> 00:10:52,000
+Yes, you can arrange.
+
+158
+00:10:52,000 --> 00:10:59,000
+This has special constructor for that here it why you may need to create array list of different capacity.
+
+159
+00:11:00,000 --> 00:11:01,000
+Let me explain.
+
+160
+00:11:01,000 --> 00:11:05,000
+You imagine that you created array list with capacity of 10 elements.
+
+161
+00:11:05,000 --> 00:11:12,000
+That means when you will add 11 element and after that sextants element and so forth, each time I should
+
+162
+00:11:12,000 --> 00:11:18,000
+copies of values from the previous array and add them to the new array that will cause some spikes in
+
+163
+00:11:18,000 --> 00:11:19,000
+our performance.
+
+164
+00:11:20,000 --> 00:11:26,000
+Then if you know that you're going to add to your rate around one million elements right after creation
+
+165
+00:11:26,000 --> 00:11:31,000
+of the array, at least it is better to set capacity at the beginning to avoid some spikes in the performance.
+
+166
+00:11:32,000 --> 00:11:38,000
+If we specify capacity for one million elements, we will avoid case when we constantly copying arrays
+
+167
+00:11:38,000 --> 00:11:45,000
+and creating new objects of arrays, keeping the old arrays in our memory until garbage collector will
+
+168
+00:11:45,000 --> 00:11:45,000
+remove them.
+
+169
+00:11:46,000 --> 00:11:50,000
+Is it clear now why you might want to create an array with the initial capacity?
+
+170
+00:11:51,000 --> 00:11:51,000
+Great.
+
+171
+00:11:51,000 --> 00:11:52,000
+Let's move on.
+
+172
+00:11:53,000 --> 00:11:55,000
+There is also one more interesting use case.
+
+173
+00:11:55,000 --> 00:12:02,000
+Imagine that you added new elements to your array list and after that you removed nine thousand one
+
+174
+00:12:02,000 --> 00:12:03,000
+hundred elements.
+
+175
+00:12:03,000 --> 00:12:07,000
+OK, there is a one thousand hundred elements in your list.
+
+176
+00:12:08,000 --> 00:12:16,000
+But what its capacity, its capacity is still one million to remove new elements from our array.
+
+177
+00:12:16,000 --> 00:12:19,000
+Inside our list we may call stream to size method.
+
+178
+00:12:20,000 --> 00:12:24,000
+This method streams the capacity of the relist instance to the list.
+
+179
+00:12:24,000 --> 00:12:24,000
+Current size.
+
+180
+00:12:25,000 --> 00:12:32,000
+OK, now you know how the dynamic extension happens in Frailest, I also promised you to explain what
+
+181
+00:12:32,000 --> 00:12:34,000
+random access is.
+
+182
+00:12:34,000 --> 00:12:37,000
+Can you see that array list implements random access?
+
+183
+00:12:38,000 --> 00:12:40,000
+Let's take a look at this interface.
+
+184
+00:12:40,000 --> 00:12:43,000
+Can you see that this is the empty interface?
+
+185
+00:12:43,000 --> 00:12:46,000
+It doesn't declare any contract for any behavior.
+
+186
+00:12:47,000 --> 00:12:48,000
+Then why do we need it at all?
+
+187
+00:12:49,000 --> 00:12:52,000
+Random access interface is a marker interface.
+
+188
+00:12:52,000 --> 00:12:57,000
+Sometimes in you would see so-called marker interfaces.
+
+189
+00:12:57,000 --> 00:13:00,000
+Why is called so xcode so?
+
+190
+00:13:00,000 --> 00:13:06,000
+Because the only reason why they exist is to mark interface with a specific type to use this information
+
+191
+00:13:06,000 --> 00:13:07,000
+in the future.
+
+192
+00:13:08,000 --> 00:13:10,000
+Probably it is still not clear for you.
+
+193
+00:13:11,000 --> 00:13:13,000
+But let me show you on the example.
+
+194
+00:13:13,000 --> 00:13:20,000
+Here is a random access interface which is used to mark any class that supports retrieval of elements
+
+195
+00:13:20,000 --> 00:13:21,000
+for the constant amount of time.
+
+196
+00:13:22,000 --> 00:13:29,000
+That's actually one of the key features of our list is a constant amount of time for reading an element
+
+197
+00:13:29,000 --> 00:13:33,000
+is because of the nature of a release and how it works under the hood.
+
+198
+00:13:33,000 --> 00:13:38,000
+To read an element, you just need to get it from array by specific index.
+
+199
+00:13:38,000 --> 00:13:40,000
+And this time is usually constant.
+
+200
+00:13:41,000 --> 00:13:45,000
+That's why our list is marked as implementation of random access.
+
+201
+00:13:46,000 --> 00:13:48,000
+Now let's see where this information is used.
+
+202
+00:13:49,000 --> 00:13:55,000
+If we would open collection class, this is class with utility methods nonwar, it will run it in the
+
+203
+00:13:55,000 --> 00:13:56,000
+separate question.
+
+204
+00:13:57,000 --> 00:14:02,000
+Right now, I just want to show you how information about market interfaces used I press control and
+
+205
+00:14:03,000 --> 00:14:09,000
+you simultaneously to search through this file and I want to search for random access words and I have
+
+206
+00:14:09,000 --> 00:14:11,000
+around fifty eight mentions.
+
+207
+00:14:11,000 --> 00:14:18,000
+You can see that random access is used with instance of operator and if closes to select specific algorithms
+
+208
+00:14:18,000 --> 00:14:22,000
+that will work the best here in binary search method.
+
+209
+00:14:22,000 --> 00:14:28,000
+You may see that in case that were passed as parameter to the mass that is compatible with random access
+
+210
+00:14:28,000 --> 00:14:31,000
+type then indexed binary search algorithm will be applied.
+
+211
+00:14:32,000 --> 00:14:35,000
+If no, then iterate a binary search method will be called.
+
+212
+00:14:36,000 --> 00:14:41,000
+And similarly, in the other method, check for compatibility with random access interface is used to
+
+213
+00:14:41,000 --> 00:14:43,000
+select the best algorithm.
+
+214
+00:14:44,000 --> 00:14:49,000
+Right now, I believe you understood the use case and how much the interface may be used.
+
+215
+00:14:49,000 --> 00:14:50,000
+That's great.
+
+216
+00:14:51,000 --> 00:14:52,000
+According to the agenda.
+
+217
+00:14:52,000 --> 00:14:55,000
+Also, we're going to cover today a few more classes.
+
+218
+00:14:55,000 --> 00:14:59,000
+Zaya Vector, Cooperton writer released and Stack.
+
+219
+00:14:59,000 --> 00:15:06,000
+While covering those, I will be super fast because they are mostly the same as I released, so I would
+
+220
+00:15:06,000 --> 00:15:11,000
+draw your attention only to the things that are different from the released here of Extra Vector.
+
+221
+00:15:12,000 --> 00:15:18,000
+It is almost the same as it released the same mechanism of storing data.
+
+222
+00:15:18,000 --> 00:15:21,000
+Here is the element data array to store elements.
+
+223
+00:15:22,000 --> 00:15:28,000
+There's only one big difference between a release and vector on assets and vector a synchronized.
+
+224
+00:15:28,000 --> 00:15:29,000
+What does that mean?
+
+225
+00:15:30,000 --> 00:15:32,000
+Let's take a look at the ad method.
+
+226
+00:15:32,000 --> 00:15:33,000
+For example.
+
+227
+00:15:33,000 --> 00:15:36,000
+Can you see the key words synchronized in the method definition?
+
+228
+00:15:37,000 --> 00:15:43,000
+We didn't learn yet this keyword in detail, but we will we will run it in the details durians and we'll
+
+229
+00:15:43,000 --> 00:15:44,000
+just write in top it.
+
+230
+00:15:45,000 --> 00:15:50,000
+But right now you can understand this keyword as a restriction for multiple threats of execution and
+
+231
+00:15:50,000 --> 00:15:52,000
+the method, but body simultaneously.
+
+232
+00:15:53,000 --> 00:15:59,000
+That means if two threats of execution want to add element, remove element or replace element of a
+
+233
+00:15:59,000 --> 00:16:03,000
+specific index, they won't be able to do this simultaneously.
+
+234
+00:16:04,000 --> 00:16:07,000
+All these operations will be performed one after another.
+
+235
+00:16:07,000 --> 00:16:11,000
+That would save you from the data inconsistency inside the vector.
+
+236
+00:16:11,000 --> 00:16:14,000
+That's why Vector is called safe container.
+
+237
+00:16:15,000 --> 00:16:16,000
+Does it make sense?
+
+238
+00:16:16,000 --> 00:16:18,000
+OK, let's go further.
+
+239
+00:16:18,000 --> 00:16:20,000
+Let me open a copy right away.
+
+240
+00:16:20,000 --> 00:16:22,000
+List the same stories here.
+
+241
+00:16:23,000 --> 00:16:23,000
+Right.
+
+242
+00:16:23,000 --> 00:16:26,000
+Or at least is a safe version of the array list.
+
+243
+00:16:27,000 --> 00:16:30,000
+Then what is the difference between vector and copywriter?
+
+244
+00:16:30,000 --> 00:16:31,000
+At least Corporan.
+
+245
+00:16:31,000 --> 00:16:32,000
+Right.
+
+246
+00:16:32,000 --> 00:16:34,000
+The list was introduced in Java version five.
+
+247
+00:16:35,000 --> 00:16:39,000
+Well, Vector was introduced in the version first in version five.
+
+248
+00:16:39,000 --> 00:16:44,000
+Engineers come up with improvements in performance for this, let's say, version of a release.
+
+249
+00:16:45,000 --> 00:16:49,000
+And we can say that right writer released is more efficient from the performance standpoint.
+
+250
+00:16:49,000 --> 00:16:54,000
+In comparison with Vector, for example, let me open add method.
+
+251
+00:16:54,000 --> 00:16:55,000
+Can you see this?
+
+252
+00:16:56,000 --> 00:16:59,000
+There is no synchronized word here, but synchronized block instead.
+
+253
+00:17:00,000 --> 00:17:06,000
+The White House improvisation is implemented in this class is different from the way it is implemented
+
+254
+00:17:06,000 --> 00:17:06,000
+in Vector.
+
+255
+00:17:07,000 --> 00:17:10,000
+That is the difference between vector unreleased and Copan.
+
+256
+00:17:10,000 --> 00:17:11,000
+Right?
+
+257
+00:17:11,000 --> 00:17:11,000
+Frailest.
+
+258
+00:17:12,000 --> 00:17:18,000
+And now let's open this attack was, as you remember from the beginning of the lesson, Stack extends
+
+259
+00:17:18,000 --> 00:17:19,000
+factor.
+
+260
+00:17:19,000 --> 00:17:22,000
+But take a look at the map that introduced instead.
+
+261
+00:17:23,000 --> 00:17:29,000
+What does this remind you of your right that is almost interface of the cube.
+
+262
+00:17:29,000 --> 00:17:32,000
+The names of the masses are almost the same.
+
+263
+00:17:32,000 --> 00:17:36,000
+Engineers don't like Stack because this is concrete glass.
+
+264
+00:17:36,000 --> 00:17:41,000
+That means there is no flexibility in using different implementation of the same API.
+
+265
+00:17:42,000 --> 00:17:44,000
+It implements LIFO principle.
+
+266
+00:17:45,000 --> 00:17:46,000
+Last in, first out.
+
+267
+00:17:47,000 --> 00:17:52,000
+We are going to review this principle in the details when we get closer to the interface.
+
+268
+00:17:52,000 --> 00:17:54,000
+So don't worry.
+
+269
+00:17:54,000 --> 00:18:01,000
+Years for now, the LIFO principle is implemented in DEC interface and in different implementation of
+
+270
+00:18:01,000 --> 00:18:02,000
+that interface.
+
+271
+00:18:02,000 --> 00:18:08,000
+But Stack was introduced in Java version one and keep the promise of backwards compatibility and to
+
+272
+00:18:08,000 --> 00:18:13,000
+make sure that programs that are written on Java version first will be successfully executed on the
+
+273
+00:18:13,000 --> 00:18:14,000
+Java version fifteens.
+
+274
+00:18:14,000 --> 00:18:17,000
+And later this class is still here.
+
+275
+00:18:18,000 --> 00:18:18,000
+That's it.
+
+276
+00:18:19,000 --> 00:18:23,000
+Now, you know, also the difference between a release vector, right.
+
+277
+00:18:23,000 --> 00:18:24,000
+And released instead.
+
+278
+00:18:25,000 --> 00:18:27,000
+Now let's recap what we have learned today.
+
+279
+00:18:28,000 --> 00:18:31,000
+Today, we investigated the Iraqi of least interface.
+
+280
+00:18:31,000 --> 00:18:36,000
+You saw how you may investigate source code and you Iraqi of any interface in eclipse.
+
+281
+00:18:37,000 --> 00:18:42,000
+Also in this lesson, we learned when we have to use implementation of the interface, such as every
+
+282
+00:18:43,000 --> 00:18:50,000
+vector writer relist, and so that we learned in detail how size of the array maybe dynamically increased
+
+283
+00:18:50,000 --> 00:18:50,000
+in there.
+
+284
+00:18:50,000 --> 00:18:56,000
+At least now you know the difference between a real E vector right at released and stack.
+
+285
+00:18:57,000 --> 00:19:00,000
+During the lesson we learned what Mark interfaces are.
+
+286
+00:19:00,000 --> 00:19:05,000
+On the example of random access interface, we learned how market interface might be used.
+
+287
+00:19:06,000 --> 00:19:08,000
+That's what we have for today.
+
+288
+00:19:08,000 --> 00:19:11,000
+Thanks a lot for your attention and see you in the next lesson.
+

19 - Java Collections Framework/005 Homework.url

@@ -0,0 +1,2 @@
+[InternetShortcut]
+URL=https://docs.google.com/document/d/1g5GRLOU4XRDCIp50n_-Dmnok-2EdoDTlAQdVm6XyBLo/edit?usp=sharing

19 - Java Collections Framework/005 LinkedList VS ArrayList, Big O Notation & Homework_en.srt

@@ -0,0 +1,1388 @@
+1
+00:00:06,000 --> 00:00:06,000
+Hello, Jim.
+
+2
+00:00:06,000 --> 00:00:10,000
+Today we are going to discuss one more implementation of list interface.
+
+3
+00:00:10,000 --> 00:00:12,000
+I'm talking about linked list.
+
+4
+00:00:12,000 --> 00:00:15,000
+In this lesson we are going to learn how Linked List works.
+
+5
+00:00:15,000 --> 00:00:20,000
+We are going to review the source code and understand when we are going to use it.
+
+6
+00:00:20,000 --> 00:00:25,000
+Also, we'll compare linked list and array list to provide you with the answer what list implementation
+
+7
+00:00:25,000 --> 00:00:28,000
+you are going to use most of the times.
+
+8
+00:00:28,000 --> 00:00:33,000
+Besides that, today in lesson we are going to have a lot of practice and I will share with you home
+
+9
+00:00:33,000 --> 00:00:36,000
+tasks that will help you to practice your knowledge in lists.
+
+10
+00:00:36,000 --> 00:00:37,000
+Let's start.
+
+11
+00:00:38,000 --> 00:00:42,000
+And first of all, let's understand how Linked List works and why it is called.
+
+12
+00:00:42,000 --> 00:00:45,000
+So this is double linked list.
+
+13
+00:00:45,000 --> 00:00:47,000
+Why it double linked.
+
+14
+00:00:47,000 --> 00:00:48,000
+Let's look at the slide.
+
+15
+00:00:48,000 --> 00:00:54,000
+This container consists of multiple objects of node type that connected between each other.
+
+16
+00:00:54,000 --> 00:00:59,000
+Each node contains some data linked to the previous node and linked to the next node.
+
+17
+00:00:59,000 --> 00:01:02,000
+That's why each node has two links.
+
+18
+00:01:02,000 --> 00:01:05,000
+That's where a name of the container comes from.
+
+19
+00:01:05,000 --> 00:01:06,000
+Linked list.
+
+20
+00:01:06,000 --> 00:01:11,000
+It is double linked because each node has the links to the next and previous element.
+
+21
+00:01:11,000 --> 00:01:12,000
+Does it make sense?
+
+22
+00:01:12,000 --> 00:01:16,000
+Now let's review the real example of linked list.
+
+23
+00:01:16,000 --> 00:01:17,000
+Take a look at the slide please.
+
+24
+00:01:17,000 --> 00:01:21,000
+For example, we have our first node a node.
+
+25
+00:01:21,000 --> 00:01:23,000
+It contains value 1000.
+
+26
+00:01:23,000 --> 00:01:26,000
+Taking into account this is the first element.
+
+27
+00:01:26,000 --> 00:01:32,000
+The link to previous element is null, but link to the next element is linked to the b node.
+
+28
+00:01:32,000 --> 00:01:36,000
+B node also contains value that is 2000.
+
+29
+00:01:36,000 --> 00:01:41,000
+Link to the previous node that is a node and link to the next node.
+
+30
+00:01:41,000 --> 00:01:44,000
+C node C node is the last one.
+
+31
+00:01:44,000 --> 00:01:48,000
+That's why link to the next node has no value.
+
+32
+00:01:48,000 --> 00:01:54,000
+And on the slide you can see that link list always stores the reference to the first and the last node.
+
+33
+00:01:54,000 --> 00:01:57,000
+It is clear now how linked list is built.
+
+34
+00:01:57,000 --> 00:02:03,000
+Understanding of this will help you a lot in understanding where and when you might want to use Linked
+
+35
+00:02:03,000 --> 00:02:05,000
+List to proceed.
+
+36
+00:02:05,000 --> 00:02:09,000
+Our lesson today, I suggest investigating the source code of the linked list.
+
+37
+00:02:09,000 --> 00:02:12,000
+Here is the source code of the linked list class.
+
+38
+00:02:12,000 --> 00:02:18,000
+As you remember from the previous lesson, it extends abstract sequential list that contains implementation
+
+39
+00:02:18,000 --> 00:02:20,000
+of some list methods.
+
+40
+00:02:20,000 --> 00:02:23,000
+Here you may see two fields of node type.
+
+41
+00:02:23,000 --> 00:02:28,000
+I believe from their names it is clear where they are referencing to the linked list.
+
+42
+00:02:28,000 --> 00:02:32,000
+Always stores the reference to the first and the last element.
+
+43
+00:02:32,000 --> 00:02:36,000
+Let's investigate how adding new element to the collection works.
+
+44
+00:02:36,000 --> 00:02:38,000
+I want to open add method.
+
+45
+00:02:38,000 --> 00:02:40,000
+Here it is.
+
+46
+00:02:40,000 --> 00:02:43,000
+We can see that link class method is invoked here.
+
+47
+00:02:44,000 --> 00:02:50,000
+Okay, let me investigate that one new variable of the node type is created and initialized with the
+
+48
+00:02:50,000 --> 00:02:53,000
+last node in the linked list.
+
+49
+00:02:53,000 --> 00:02:58,000
+After that new node object is created, special constructor is called.
+
+50
+00:02:58,000 --> 00:03:05,000
+We are passing reference to the last node elements that we want to add and new value.
+
+51
+00:03:05,000 --> 00:03:09,000
+Let me open this constructor to investigate what is happening there.
+
+52
+00:03:09,000 --> 00:03:12,000
+And now we may receive two answers.
+
+53
+00:03:12,000 --> 00:03:16,000
+The first answer is on the question what is node class?
+
+54
+00:03:16,000 --> 00:03:21,000
+As you can see, node is a static nested class and it's private.
+
+55
+00:03:21,000 --> 00:03:26,000
+That means that instances of the node class can be created only from the linked list class.
+
+56
+00:03:26,000 --> 00:03:33,000
+You also may notice that it is not so big and it doesn't have any behavior, only state.
+
+57
+00:03:33,000 --> 00:03:36,000
+The state of the node class is described in three fields.
+
+58
+00:03:36,000 --> 00:03:40,000
+They are item, next, and previous.
+
+59
+00:03:40,000 --> 00:03:44,000
+And the second answer is in this constructor.
+
+60
+00:03:44,000 --> 00:03:48,000
+So the first argument is used to initialize previous variable.
+
+61
+00:03:48,000 --> 00:03:54,000
+The second method argument is used to initialize the value of the current node, and the third method
+
+62
+00:03:54,000 --> 00:03:58,000
+argument is used to initialize the next variable.
+
+63
+00:03:58,000 --> 00:04:05,000
+Now when we know this, let's get back to the add method and when new node is created, last variable
+
+64
+00:04:05,000 --> 00:04:11,000
+is pointing out to the new node and in case last node was null, that means list was empty.
+
+65
+00:04:12,000 --> 00:04:15,000
+Thus new node should become the first element in the list.
+
+66
+00:04:15,000 --> 00:04:19,000
+If no, then we have to change the next reference in the node.
+
+67
+00:04:19,000 --> 00:04:22,000
+That was the last note so much time ago.
+
+68
+00:04:22,000 --> 00:04:28,000
+What I want you to understand, I want you to understand that to insert elements in linked list, it
+
+69
+00:04:28,000 --> 00:04:33,000
+is enough just to change references to the previous and the next element.
+
+70
+00:04:33,000 --> 00:04:34,000
+That's it.
+
+71
+00:04:34,000 --> 00:04:39,000
+If you remember array list that we learned in previous lesson, you should already know that in array
+
+72
+00:04:39,000 --> 00:04:44,000
+list, we always need to copy values from previous array and to create new arrays.
+
+73
+00:04:44,000 --> 00:04:50,000
+If we want to remove elements from the middle or beginning of the list, or to insert elements at the
+
+74
+00:04:50,000 --> 00:04:57,000
+beginning or in the middle of the list in the linked list, these operations may be done much faster
+
+75
+00:04:57,000 --> 00:04:58,000
+and significantly easier.
+
+76
+00:04:59,000 --> 00:05:01,000
+Also, I'd like you to pay attention to the.
+
+77
+00:05:01,000 --> 00:05:04,000
+The fact that Linked List implements that interface.
+
+78
+00:05:04,000 --> 00:05:06,000
+Let me open it.
+
+79
+00:05:06,000 --> 00:05:09,000
+Deck interface extends queue.
+
+80
+00:05:09,000 --> 00:05:13,000
+This is lesson not about queue and deck interface, but it is hard.
+
+81
+00:05:13,000 --> 00:05:19,000
+Not to mention that linked List is also one of the most popular implementations of the queue interface.
+
+82
+00:05:19,000 --> 00:05:26,000
+And to be honest, I used link list more often when I needed implementation of the queue, but not implementation
+
+83
+00:05:26,000 --> 00:05:27,000
+of the list.
+
+84
+00:05:27,000 --> 00:05:28,000
+Why?
+
+85
+00:05:28,000 --> 00:05:30,000
+I'm going to explain you this in a minute.
+
+86
+00:05:31,000 --> 00:05:34,000
+So knowing this fact, don't feel wondered why.
+
+87
+00:05:34,000 --> 00:05:42,000
+Linked list also has such methods as at first, at last remove first, remove last, get first, get
+
+88
+00:05:42,000 --> 00:05:43,000
+lost and others.
+
+89
+00:05:43,000 --> 00:05:50,000
+Now you know that linked list must give implementations to these methods since it implements deck interface.
+
+90
+00:05:50,000 --> 00:05:57,000
+We will not review these methods today since this is lesson about implementation of the list interface,
+
+91
+00:05:57,000 --> 00:06:03,000
+but we will discuss the other methods for sure during the lessons about queue, so don't worry.
+
+92
+00:06:03,000 --> 00:06:09,000
+Now I suggest practicing a bit with using linked list and array list for the sake of the demo.
+
+93
+00:06:09,000 --> 00:06:12,000
+Before the lesson I created this demo file.
+
+94
+00:06:12,000 --> 00:06:15,000
+I will leave a link to it in the lesson attachments.
+
+95
+00:06:15,000 --> 00:06:21,000
+And if you have all my training project cloned from the GitHub, just pull the latest changes.
+
+96
+00:06:21,000 --> 00:06:25,000
+Let me also run this program and we will explore console output together.
+
+97
+00:06:26,000 --> 00:06:27,000
+Okay.
+
+98
+00:06:27,000 --> 00:06:34,000
+As I begin here, I created two variables of type list, both of them initialized with array list objects.
+
+99
+00:06:34,000 --> 00:06:36,000
+Do not forget to do imports.
+
+100
+00:06:37,000 --> 00:06:40,000
+Eclipse will remind you to do that, so don't worry.
+
+101
+00:06:40,000 --> 00:06:47,000
+You also can see that the first list here is underlined with yellow line, the same as array list here.
+
+102
+00:06:47,000 --> 00:06:51,000
+But in the next line there are no any warnings.
+
+103
+00:06:51,000 --> 00:06:54,000
+What is the difference between these two declarations?
+
+104
+00:06:54,000 --> 00:07:00,000
+Probably you already saw in the source code this diamond operator, but you couldn't understand.
+
+105
+00:07:00,000 --> 00:07:01,000
+What does that mean?
+
+106
+00:07:01,000 --> 00:07:03,000
+Let me explain you this.
+
+107
+00:07:03,000 --> 00:07:09,000
+On the next example, I add string object to the list one and I also add integer object to the list
+
+108
+00:07:09,000 --> 00:07:10,000
+one.
+
+109
+00:07:10,000 --> 00:07:17,000
+Now my list one contains objects of different types, but all of them are compatible with the one type
+
+110
+00:07:18,000 --> 00:07:19,000
+object.
+
+111
+00:07:19,000 --> 00:07:26,000
+That's why when we want to get element of this container, we always get object of type object.
+
+112
+00:07:26,000 --> 00:07:28,000
+Can you understand why?
+
+113
+00:07:28,000 --> 00:07:34,000
+Because Java compiler doesn't know what object will be on the first index in the list and what its type.
+
+114
+00:07:35,000 --> 00:07:37,000
+Now let's look at the second list.
+
+115
+00:07:37,000 --> 00:07:44,000
+I also can add string in it, but I can't add integer because this would cause compilation error.
+
+116
+00:07:44,000 --> 00:07:48,000
+Why this called generic mechanism.
+
+117
+00:07:48,000 --> 00:07:53,000
+We are going to have separate lesson where I'm going to describe you generics in detail.
+
+118
+00:07:53,000 --> 00:07:58,000
+But right now you have to understand it at least on the high level because this will help you during
+
+119
+00:07:58,000 --> 00:08:00,000
+the homework implementation.
+
+120
+00:08:00,000 --> 00:08:07,000
+Here in Diamond operator, we specify type of elements in this list that is assigned for our Compilator
+
+121
+00:08:07,000 --> 00:08:11,000
+that in this list we will store only string objects.
+
+122
+00:08:11,000 --> 00:08:17,000
+We also have to specify diamond operator here next to specific collection implementation before the
+
+123
+00:08:17,000 --> 00:08:18,000
+Java version seven.
+
+124
+00:08:18,000 --> 00:08:25,000
+Engineers should also specify type here, but after Java version seven, in case type is the same as
+
+125
+00:08:25,000 --> 00:08:28,000
+it is specified for variable, we can keep it empty.
+
+126
+00:08:28,000 --> 00:08:32,000
+This would be the same as in case we would specify type here.
+
+127
+00:08:33,000 --> 00:08:37,000
+That's why Compilator allows only add string objects there.
+
+128
+00:08:37,000 --> 00:08:40,000
+Pretty cool feature, don't you think so?
+
+129
+00:08:40,000 --> 00:08:42,000
+This saves developer nerves.
+
+130
+00:08:42,000 --> 00:08:48,000
+When we get object from the container, call some method on it and we see some exception and program
+
+131
+00:08:48,000 --> 00:08:55,000
+stops execution because somebody in some other method put in the container object of incompatible type.
+
+132
+00:08:55,000 --> 00:09:02,000
+And when compilator is sure that will store only string objects there, we also can retrieve objects
+
+133
+00:09:02,000 --> 00:09:03,000
+of the string type.
+
+134
+00:09:03,000 --> 00:09:09,000
+For example, here when I get element from zero index, I get object of string type.
+
+135
+00:09:09,000 --> 00:09:13,000
+Hope this brings some clarity on how you may use diamond operator.
+
+136
+00:09:13,000 --> 00:09:19,000
+More advanced scenarios and how generics work will be reviewed during the separate lesson.
+
+137
+00:09:19,000 --> 00:09:21,000
+Okay, let's move on.
+
+138
+00:09:21,000 --> 00:09:28,000
+Here you may see that I initialized my variable of list type with linked list object, and this is one
+
+139
+00:09:28,000 --> 00:09:30,000
+of the advantages of Java Collections framework.
+
+140
+00:09:30,000 --> 00:09:31,000
+Here it is.
+
+141
+00:09:31,000 --> 00:09:37,000
+We may change implementation of the list, but the application programming interface is the same.
+
+142
+00:09:37,000 --> 00:09:41,000
+I still may use the same methods and count on the same result.
+
+143
+00:09:41,000 --> 00:09:48,000
+That's why all examples that you are going to see in this and in the next lessons will be the same for
+
+144
+00:09:48,000 --> 00:09:51,000
+different implementations of the specific interfaces.
+
+145
+00:09:51,000 --> 00:09:56,000
+For example, if we are reviewing list interface, you may use different implementations of the list.
+
+146
+00:09:56,000 --> 00:10:03,000
+All of them have the same set of methods, but the way how these methods works on site are different
+
+147
+00:10:03,000 --> 00:10:07,000
+and that may impact on your decision which list implementation to choose.
+
+148
+00:10:07,000 --> 00:10:08,000
+Does it make sense?
+
+149
+00:10:09,000 --> 00:10:14,000
+Now let me share with you the tip and the popular way to initialize some lists.
+
+150
+00:10:14,000 --> 00:10:19,000
+All lists implementation have constructors that takes collection of elements and initialize new list
+
+151
+00:10:19,000 --> 00:10:21,000
+with these elements.
+
+152
+00:10:21,000 --> 00:10:27,000
+Arrays class has as list method that takes multiple parameters of the same type and returns the list,
+
+153
+00:10:27,000 --> 00:10:32,000
+which in turn we use here to pass it to the constructor of array list.
+
+154
+00:10:32,000 --> 00:10:38,000
+So here is the example how you can initialize your list with multiple elements in one line.
+
+155
+00:10:38,000 --> 00:10:44,000
+For learning and debugging purposes, you always may pass list implementations to the println method,
+
+156
+00:10:44,000 --> 00:10:50,000
+because all list implementations have to string method overridden to display elements in such way as
+
+157
+00:10:50,000 --> 00:10:52,000
+you can see here in console.
+
+158
+00:10:52,000 --> 00:10:56,000
+Also, another important and practical thing to share with you.
+
+159
+00:10:56,000 --> 00:11:00,000
+All collection implementations can be used in for each loop.
+
+160
+00:11:00,000 --> 00:11:05,000
+I believe that you remember that collection interface implements a terrible interface.
+
+161
+00:11:05,000 --> 00:11:12,000
+This fact guarantees that each implementation of collection should have iterator method that will return
+
+162
+00:11:12,000 --> 00:11:17,000
+iterator object that knows how to iterate over the collection of elements.
+
+163
+00:11:17,000 --> 00:11:22,000
+That's why all collections can be used in for each loops according to Java syntax.
+
+164
+00:11:22,000 --> 00:11:24,000
+And you can see example here.
+
+165
+00:11:24,000 --> 00:11:25,000
+So now you.
+
+166
+00:11:25,000 --> 00:11:32,000
+Member that all arrays and everything that implements iterable interface, even if this your own custom
+
+167
+00:11:32,000 --> 00:11:33,000
+class may be used in.
+
+168
+00:11:33,000 --> 00:11:34,000
+For rich loops.
+
+169
+00:11:35,000 --> 00:11:38,000
+And here you can see example of clear method.
+
+170
+00:11:38,000 --> 00:11:42,000
+What I would recommend is to play with other methods like I do here.
+
+171
+00:11:43,000 --> 00:11:47,000
+Call clear method, call other methods and investigate console output.
+
+172
+00:11:47,000 --> 00:11:52,000
+Writing code and calling different methods will help you to understand material better.
+
+173
+00:11:52,000 --> 00:11:57,000
+And probably that would cause some questions and I will be always happy to answer those.
+
+174
+00:11:58,000 --> 00:12:04,000
+Now, when you know how to use list implementations in Java source code, I suggest understanding what
+
+175
+00:12:04,000 --> 00:12:09,000
+list implementations you have to use, in which particular case, and to make a choice, I'd like to
+
+176
+00:12:09,000 --> 00:12:12,000
+explain you what big O notation is.
+
+177
+00:12:12,000 --> 00:12:18,000
+Big O notation is a mathematical notation that describes the limiting behavior of a function when the
+
+178
+00:12:18,000 --> 00:12:21,000
+argument tends towards a particular value or infinity.
+
+179
+00:12:21,000 --> 00:12:27,000
+We are not going to do math in this course, but we need to understand big O notation while working
+
+180
+00:12:27,000 --> 00:12:31,000
+with different implementations of collections in computer science.
+
+181
+00:12:31,000 --> 00:12:38,000
+Big O notation is used to classify algorithms according to how they run time or space requirements grow
+
+182
+00:12:38,000 --> 00:12:40,000
+as the input size grows.
+
+183
+00:12:40,000 --> 00:12:47,000
+In very simple words, big O notation can tell us how efficient algorithm as number of elements that
+
+184
+00:12:47,000 --> 00:12:49,000
+algorithm work with increases.
+
+185
+00:12:49,000 --> 00:12:52,000
+We are going to use only few classes of functions.
+
+186
+00:12:53,000 --> 00:12:55,000
+Let me explain you what they mean.
+
+187
+00:12:55,000 --> 00:12:58,000
+Oh one that is constant.
+
+188
+00:12:58,000 --> 00:13:00,000
+For example, get an element from array by.
+
+189
+00:13:00,000 --> 00:13:03,000
+Its index is always constant.
+
+190
+00:13:04,000 --> 00:13:06,000
+Oh n let us linear clause.
+
+191
+00:13:06,000 --> 00:13:12,000
+That means that performance of the function directly depends on the number of elements.
+
+192
+00:13:12,000 --> 00:13:20,000
+For example, function of finding element in unsorted array has o n notation because you have to check
+
+193
+00:13:20,000 --> 00:13:24,000
+each element one by one to find the exactly one you need.
+
+194
+00:13:25,000 --> 00:13:30,000
+This operation takes time, and the time will depend on the number of elements.
+
+195
+00:13:30,000 --> 00:13:32,000
+Does it make sense now?
+
+196
+00:13:33,000 --> 00:13:33,000
+Oh.
+
+197
+00:13:33,000 --> 00:13:34,000
+Logarithm.
+
+198
+00:13:34,000 --> 00:13:41,000
+N that is, logarithmic class function of finding element in binary tree has all log n notation.
+
+199
+00:13:42,000 --> 00:13:45,000
+For example, imagine that you have sorted array of elements.
+
+200
+00:13:45,000 --> 00:13:51,000
+If you are looking for specific value, you can predict in which part of the array it is most likely
+
+201
+00:13:51,000 --> 00:13:55,000
+stored, and you shouldn't iterate exactly over each element.
+
+202
+00:13:55,000 --> 00:13:59,000
+We are going to learn what binary trees are in the next lessons.
+
+203
+00:13:59,000 --> 00:14:05,000
+Right now you can understand this as something what still depends on the number of elements, but the
+
+204
+00:14:05,000 --> 00:14:07,000
+dependency is not linear.
+
+205
+00:14:08,000 --> 00:14:12,000
+I try to say this as easy as possible without going deep in mathematic.
+
+206
+00:14:12,000 --> 00:14:16,000
+Believe me when you will see this on practice, that would be much easier.
+
+207
+00:14:17,000 --> 00:14:22,000
+Now I'd like to answer the question which implementation of list to use and when.
+
+208
+00:14:22,000 --> 00:14:27,000
+The first thing you have to answer during the interview, in case you would be asked what would you
+
+209
+00:14:27,000 --> 00:14:27,000
+use?
+
+210
+00:14:27,000 --> 00:14:29,000
+Linked list or array list?
+
+211
+00:14:29,000 --> 00:14:31,000
+You should ask in which environment we plan to use.
+
+212
+00:14:31,000 --> 00:14:37,000
+List implementation and regarding amount of data to answer when to use which implementation.
+
+213
+00:14:37,000 --> 00:14:43,000
+Let's review performance of each list implementation and based on this we will give an answer.
+
+214
+00:14:44,000 --> 00:14:48,000
+Now let's compare big O notation of array list and linked list.
+
+215
+00:14:48,000 --> 00:14:53,000
+Here on the slide you can see big O notation for different operations for array and linked lists.
+
+216
+00:14:54,000 --> 00:14:56,000
+Let me go over each one.
+
+217
+00:14:56,000 --> 00:14:59,000
+Get operation in array list is constant.
+
+218
+00:14:59,000 --> 00:15:06,000
+That's why we see here all one notation when on the other hand get element from linked list has linear
+
+219
+00:15:06,000 --> 00:15:07,000
+complexity.
+
+220
+00:15:07,000 --> 00:15:12,000
+And I want you to not memorize big O notation, but understand it instead.
+
+221
+00:15:12,000 --> 00:15:18,000
+Can you understand why retrieving elements from linked list is a linear function class?
+
+222
+00:15:18,000 --> 00:15:19,000
+Correct.
+
+223
+00:15:19,000 --> 00:15:25,000
+Because we have linked list without indices, and to get any specific element, we should iterate over
+
+224
+00:15:25,000 --> 00:15:29,000
+each element unless we would reach exactly the one that we need.
+
+225
+00:15:30,000 --> 00:15:33,000
+Linked list also defines from which side of the list to start.
+
+226
+00:15:33,000 --> 00:15:39,000
+If index in the second half of the list, then iteration starts from the end of the list.
+
+227
+00:15:39,000 --> 00:15:44,000
+In case index is in the first half of the list, then iteration starts from the beginning.
+
+228
+00:15:44,000 --> 00:15:45,000
+Does it make sense?
+
+229
+00:15:46,000 --> 00:15:48,000
+Okay, then let's move further.
+
+230
+00:15:49,000 --> 00:15:50,000
+Add elements to the list.
+
+231
+00:15:50,000 --> 00:15:56,000
+Array list adds always for constant amount of time, the same as linked list.
+
+232
+00:15:56,000 --> 00:15:58,000
+I'd like to make a note here.
+
+233
+00:15:58,000 --> 00:16:02,000
+This notation is from the book Java Generics and Collections by Philip Wadler.
+
+234
+00:16:03,000 --> 00:16:09,000
+You may find it on the internet if you wish, and I want to say that this is an average value listed
+
+235
+00:16:09,000 --> 00:16:10,000
+here.
+
+236
+00:16:10,000 --> 00:16:11,000
+Why?
+
+237
+00:16:11,000 --> 00:16:16,000
+Because adding elements to the end would take constant amount of time in both containers.
+
+238
+00:16:16,000 --> 00:16:20,000
+But for array list, you already know one exception.
+
+239
+00:16:20,000 --> 00:16:26,000
+That is the case when arrays inside the array list is expanded, and additional time is needed to copy
+
+240
+00:16:26,000 --> 00:16:28,000
+all elements from all the way to the new array.
+
+241
+00:16:29,000 --> 00:16:31,000
+Also, there is another note.
+
+242
+00:16:31,000 --> 00:16:36,000
+Adding elements at the beginning or in the middle of a release would also trigger creation of the new
+
+243
+00:16:36,000 --> 00:16:39,000
+array, and depends on the actual size of the array.
+
+244
+00:16:39,000 --> 00:16:43,000
+This can take some time, even despite native methods written on C plus.
+
+245
+00:16:43,000 --> 00:16:50,000
+Plus is used to copy an array and it works really fast on huge amount of data that may cause some performance
+
+246
+00:16:50,000 --> 00:16:51,000
+issues.
+
+247
+00:16:51,000 --> 00:16:53,000
+That is something what you have to remember.
+
+248
+00:16:53,000 --> 00:16:55,000
+Let's move on.
+
+249
+00:16:55,000 --> 00:16:56,000
+Remove operation.
+
+250
+00:16:56,000 --> 00:17:05,000
+This algorithm in array list is linear, the same as in linked list, but in general it should work
+
+251
+00:17:05,000 --> 00:17:13,000
+faster in linked list on huge amount of data because to remove element from the middle or beginning
+
+252
+00:17:13,000 --> 00:17:16,000
+of the array list, we have to find the element first.
+
+253
+00:17:16,000 --> 00:17:20,000
+And the more elements, the more time it would take to find it.
+
+254
+00:17:20,000 --> 00:17:28,000
+And then after removing it from an array, we need to merge two parts of array to not have empty element
+
+255
+00:17:28,000 --> 00:17:30,000
+inside the array.
+
+256
+00:17:30,000 --> 00:17:32,000
+So we need to copy array.
+
+257
+00:17:32,000 --> 00:17:39,000
+And again, the time that it will take will depend on the number of elements with linked list.
+
+258
+00:17:39,000 --> 00:17:42,000
+We need to spend time to find the element.
+
+259
+00:17:42,000 --> 00:17:45,000
+The more elements, the longer it would take.
+
+260
+00:17:45,000 --> 00:17:51,000
+And when we found the element, we don't need to copy all the data structure to merge it back again.
+
+261
+00:17:52,000 --> 00:17:54,000
+Because this is not an array.
+
+262
+00:17:54,000 --> 00:17:55,000
+This is a linked list.
+
+263
+00:17:55,000 --> 00:18:01,000
+So we have to only change the references to the next and previous elements.
+
+264
+00:18:01,000 --> 00:18:07,000
+Even despite the summary of big O notation between ArrayList and Linkedlist looks similar.
+
+265
+00:18:07,000 --> 00:18:11,000
+They would have different performance on different volumes of data.
+
+266
+00:18:11,000 --> 00:18:17,000
+That's why understanding how they work is essential to understand their performance.
+
+267
+00:18:17,000 --> 00:18:23,000
+You are going to have a homework to find out the difference in performance on different volumes of data.
+
+268
+00:18:23,000 --> 00:18:26,000
+Now let's make a conclusion based on these facts.
+
+269
+00:18:26,000 --> 00:18:32,000
+We have to use linked list when we plan constantly add elements at the beginning or at the end of the
+
+270
+00:18:32,000 --> 00:18:32,000
+list.
+
+271
+00:18:33,000 --> 00:18:38,000
+We also should opt for link list when we want to remove elements constantly from the beginning of the
+
+272
+00:18:38,000 --> 00:18:39,000
+list.
+
+273
+00:18:39,000 --> 00:18:45,000
+If we plan to use container to always add elements to the end and read elements from the list, then
+
+274
+00:18:45,000 --> 00:18:47,000
+array list is our choice.
+
+275
+00:18:47,000 --> 00:18:54,000
+But I told you that algorithm of array copying works really fast, and everything will depend on the
+
+276
+00:18:54,000 --> 00:18:56,000
+amount of data that we are working with.
+
+277
+00:18:56,000 --> 00:19:02,000
+I'm going to give you a home task where you would be able to test whether linked list really has advantage
+
+278
+00:19:02,000 --> 00:19:05,000
+over array list while working with not so big amount of data.
+
+279
+00:19:06,000 --> 00:19:09,000
+But I will give you insights even before you finish that task.
+
+280
+00:19:09,000 --> 00:19:15,000
+In majority of cases, even during the work with 1 million of elements that are relatively small objects.
+
+281
+00:19:15,000 --> 00:19:19,000
+Array list still is going to be faster than linked list.
+
+282
+00:19:20,000 --> 00:19:26,000
+And with regards of the business cases, I would say that array list is your choice almost in 99% of
+
+283
+00:19:26,000 --> 00:19:27,000
+cases.
+
+284
+00:19:27,000 --> 00:19:32,000
+The rest of the cases are when you need either threadsafe container, or you have millions of objects
+
+285
+00:19:32,000 --> 00:19:36,000
+that you need to add in the beginning of the list and constantly remove them.
+
+286
+00:19:37,000 --> 00:19:42,000
+I believe you would agree with me that it is even hard to come up with example here of such case.
+
+287
+00:19:42,000 --> 00:19:47,000
+Time for linked list will come when we will talk about queues, will discover that linked list works
+
+288
+00:19:47,000 --> 00:19:51,000
+the best for us if we need implementation of queue or deck.
+
+289
+00:19:52,000 --> 00:19:54,000
+Now let's recap what we have learned today.
+
+290
+00:19:55,000 --> 00:19:57,000
+Today we learned how linked list works.
+
+291
+00:19:57,000 --> 00:20:03,000
+Now we know what the node type is and how nodes are connected between each other in linked list.
+
+292
+00:20:04,000 --> 00:20:07,000
+We had a practice with link list and array list.
+
+293
+00:20:07,000 --> 00:20:10,000
+Now you even know how to use generics.
+
+294
+00:20:10,000 --> 00:20:16,000
+We learned what big O notation is and using this knowledge we compared link list and array lists.
+
+295
+00:20:16,000 --> 00:20:21,000
+Now you know, in which case you have to opt for either array list or link list.
+
+296
+00:20:21,000 --> 00:20:24,000
+And now I suggest reviewing your homework.
+
+297
+00:20:25,000 --> 00:20:27,000
+I have a lot of tasks for you today.
+
+298
+00:20:27,000 --> 00:20:31,000
+All of them have different level of complexity, but nothing what we didn't discuss.
+
+299
+00:20:31,000 --> 00:20:37,000
+So the first exercise is to test and compare the performance of array list and linked list.
+
+300
+00:20:37,000 --> 00:20:42,000
+It is not complex from the coding standpoint, but it is also good for you to practice with creating
+
+301
+00:20:42,000 --> 00:20:48,000
+objects of different types, declare variables and to remember, in which case you have to use which
+
+302
+00:20:48,000 --> 00:20:49,000
+container.
+
+303
+00:20:49,000 --> 00:20:54,000
+Here is a guidance what methods should be created and methods declarations.
+
+304
+00:20:54,000 --> 00:20:57,000
+And here operations that I'd like you to test.
+
+305
+00:20:57,000 --> 00:21:02,000
+We are going to insert different number of elements into the beginning, middle and at the end of the
+
+306
+00:21:02,000 --> 00:21:03,000
+list.
+
+307
+00:21:03,000 --> 00:21:09,000
+We'll test these operations with 110,000 and 1100 elements.
+
+308
+00:21:09,000 --> 00:21:14,000
+Also, we will test removal of elements from the beginning, middle and the end of the list.
+
+309
+00:21:14,000 --> 00:21:18,000
+We'll perform the same operations with array list and linked list.
+
+310
+00:21:18,000 --> 00:21:23,000
+And we'll measure how much time execution of specific method takes with array list and specific number
+
+311
+00:21:23,000 --> 00:21:25,000
+of elements and linked list.
+
+312
+00:21:26,000 --> 00:21:30,000
+After you're done with coding, I want you to fill out these tables.
+
+313
+00:21:30,000 --> 00:21:36,000
+You may see that these tables have different rows and columns based on which list implementation you
+
+314
+00:21:36,000 --> 00:21:38,000
+used and what operation you did.
+
+315
+00:21:38,000 --> 00:21:43,000
+If you are wondering how you can measure the time of method execution, here is a small hint for you.
+
+316
+00:21:43,000 --> 00:21:47,000
+You can capture time before some method execution.
+
+317
+00:21:47,000 --> 00:21:52,000
+After that call some method and after that calculate delta this value.
+
+318
+00:21:52,000 --> 00:21:58,000
+You can insert into the table after you finished, you may compare your results with my results and
+
+319
+00:21:58,000 --> 00:22:00,000
+to evaluate the trends.
+
+320
+00:22:00,000 --> 00:22:06,000
+I don't want to make any conclusions right now, primarily because some of them were already discussed
+
+321
+00:22:06,000 --> 00:22:07,000
+during the lesson.
+
+322
+00:22:07,000 --> 00:22:11,000
+And the other reason is that I want you to draw your own conclusions.
+
+323
+00:22:12,000 --> 00:22:17,000
+The second exercise here is to update existing backend system for online store.
+
+324
+00:22:17,000 --> 00:22:22,000
+It is a console application and you may find it in this repository in this package.
+
+325
+00:22:22,000 --> 00:22:24,000
+This solution uses arrays.
+
+326
+00:22:24,000 --> 00:22:28,000
+Your task is to substitute arrays with list implementations.
+
+327
+00:22:28,000 --> 00:22:30,000
+You are provided with a sample project.
+
+328
+00:22:30,000 --> 00:22:31,000
+Here.
+
+329
+00:22:31,000 --> 00:22:36,000
+Your goal is not to break anything and to make sure that all scenarios work as expected.
+
+330
+00:22:37,000 --> 00:22:42,000
+This task should give you a clear understanding of how you are going to use list implementations in
+
+331
+00:22:42,000 --> 00:22:43,000
+your applications.
+
+332
+00:22:43,000 --> 00:22:49,000
+And the last but not the least task is to create your own implementation of custom list interface.
+
+333
+00:22:49,000 --> 00:22:54,000
+You have to create interface first with such content, and after that you have to create class.
+
+334
+00:22:54,000 --> 00:22:57,000
+And to implement this interface in it.
+
+335
+00:22:57,000 --> 00:22:58,000
+Team.
+
+336
+00:22:58,000 --> 00:23:04,000
+I promise you in case you would implement these three exercises, you would understand list implementations
+
+337
+00:23:04,000 --> 00:23:05,000
+like nobody else.
+
+338
+00:23:05,000 --> 00:23:07,000
+Remember learning programming?
+
+339
+00:23:07,000 --> 00:23:13,000
+It is about coding and a little bit about reading, but definitely not vice versa.
+
+340
+00:23:13,000 --> 00:23:18,000
+And by the way, you also shouldn't worry in case something is hard for you to implement.
+
+341
+00:23:18,000 --> 00:23:20,000
+We are all learning new things here.
+
+342
+00:23:20,000 --> 00:23:24,000
+I'm going to leave links to the solution in attachments to this video.
+
+343
+00:23:24,000 --> 00:23:31,000
+So even in case you can't complete some of the tasks, feel free to look through my solution and rewrite
+
+344
+00:23:31,000 --> 00:23:36,000
+it very attentively and always ask me questions in case you have any.
+
+345
+00:23:36,000 --> 00:23:38,000
+That's all for today.
+
+346
+00:23:38,000 --> 00:23:40,000
+Thanks a lot for your attention and have a great day.
+
+347
+00:23:40,000 --> 00:23:42,000
+See you in the next lesson.
+

19 - Java Collections Framework/005 Solution-for-DefaultMyList-coding-exercise.url

@@ -0,0 +1,2 @@
+[InternetShortcut]
+URL=https://github.com/AndriiPiatakha/learnit_java_core/blob/master/src/com/itbulls/learnit/javacore/jcf/collections/list/hw/DefaultMyList.java

19 - Java Collections Framework/005 Solution-of-the-homework-Backend-system-for-online-store-with-list.url

@@ -0,0 +1,2 @@
+[InternetShortcut]
+URL=https://github.com/AndriiPiatakha/learnit_java_core/tree/master/src/com/itbulls/learnit/javacore/jcf/hw/onlinestore/withlist

19 - Java Collections Framework/005 Solution-of-the-homework-DefaultList-and-Performance-of-ArrayList-vs-LinkedList.url

@@ -0,0 +1,2 @@
+[InternetShortcut]
+URL=https://github.com/AndriiPiatakha/learnit_java_core/tree/master/src/com/itbulls/learnit/javacore/jcf/collections/list/hw

19 - Java Collections Framework/005 Source-code-of-the-example-used-in-the-lesso.url

@@ -0,0 +1,2 @@
+[InternetShortcut]
+URL=https://github.com/AndriiPiatakha/learnit_java_core/blob/master/src/com/itbulls/learnit/javacore/jcf/collections/list/ListDemo.java

19 - Java Collections Framework/005 Template-project-for-your-homework.url

@@ -0,0 +1,2 @@
+[InternetShortcut]
+URL=https://github.com/AndriiPiatakha/learnit_java_core/tree/master/src/com/itbulls/learnit/javacore/jcf/hw/onlinestore/withoutlist

19 - Java Collections Framework/008 Comparator and Comparable_en.srt

@@ -0,0 +1,912 @@
+1
+00:00:06,000 --> 00:00:11,000
+Hello, dear students and this class, and we are going to learn what comparator Uncomparable is, we'll
+
+2
+00:00:11,000 --> 00:00:17,000
+review these two interfaces and we'll answer when we have to use them after the lesson and you'll understand
+
+3
+00:00:17,000 --> 00:00:21,000
+the difference between them and will never confuse these two interfaces.
+
+4
+00:00:22,000 --> 00:00:27,000
+Today on Real Example, I'm going to show you how you can search your collection of elements.
+
+5
+00:00:27,000 --> 00:00:31,000
+We're also going to learn what the quicksort algorithm is.
+
+6
+00:00:31,000 --> 00:00:32,000
+Let's start.
+
+7
+00:00:32,000 --> 00:00:38,000
+And today, the best way to learn the topic is to jump directly to the eclipse and investigate the source
+
+8
+00:00:38,000 --> 00:00:38,000
+code.
+
+9
+00:00:39,000 --> 00:00:44,000
+We are going to start our lesson today from the interface over you compare.
+
+10
+00:00:44,000 --> 00:00:49,000
+The interface has only one abstract method that you have to implement in your own implementation.
+
+11
+00:00:50,000 --> 00:00:52,000
+The method name is compare.
+
+12
+00:00:52,000 --> 00:00:55,000
+This method takes two methods arguments.
+
+13
+00:00:55,000 --> 00:01:00,000
+This may be different reference types, as you can see here, but they should be the same.
+
+14
+00:01:00,000 --> 00:01:06,000
+This method, according to the interface contracts, should compare to objects and tell us what objects
+
+15
+00:01:06,000 --> 00:01:08,000
+should go before the other one.
+
+16
+00:01:08,000 --> 00:01:10,000
+How it can tell us this.
+
+17
+00:01:10,000 --> 00:01:12,000
+My return in value.
+
+18
+00:01:12,000 --> 00:01:19,000
+Everything is simple here in case the first argument is less than the second one negative integer is
+
+19
+00:01:19,000 --> 00:01:20,000
+returned.
+
+20
+00:01:20,000 --> 00:01:27,000
+In case the first argument is equal to the second argument, then zero is returned and only in case
+
+21
+00:01:27,000 --> 00:01:29,000
+the first argument is more than the second one.
+
+22
+00:01:30,000 --> 00:01:36,000
+In this case, positive integer is returned and this function is enough to source all elements in your
+
+23
+00:01:36,000 --> 00:01:38,000
+collection, according to the quicksort algorithm.
+
+24
+00:01:39,000 --> 00:01:43,000
+And a bit later today, we're going to learn how quicksort algorithm works.
+
+25
+00:01:44,000 --> 00:01:50,000
+Right now, let's investigate what else we have here in the comparator interface we have here.
+
+26
+00:01:50,000 --> 00:01:56,000
+Absaroka equals method, but it will have implementation in any class because each class is extended
+
+27
+00:01:56,000 --> 00:01:57,000
+from object and object.
+
+28
+00:01:57,000 --> 00:02:00,000
+Class has implementation of equals method.
+
+29
+00:02:01,000 --> 00:02:05,000
+That's Y equals usually is not overridden in comparative implementations.
+
+30
+00:02:06,000 --> 00:02:11,000
+Now I want to share with you information how you can quickly get comparator for natural and inverse
+
+31
+00:02:11,000 --> 00:02:12,000
+ordering.
+
+32
+00:02:12,000 --> 00:02:18,000
+Here is a reverse order method IT comparator that source items in reverse order.
+
+33
+00:02:19,000 --> 00:02:22,000
+But what is reverse order to explain this?
+
+34
+00:02:22,000 --> 00:02:23,000
+Let me open them up.
+
+35
+00:02:23,000 --> 00:02:26,000
+Programs that I prepared specially for this lesson.
+
+36
+00:02:27,000 --> 00:02:30,000
+Let me also run it to explore console output together with you.
+
+37
+00:02:31,000 --> 00:02:33,000
+Imagine that we have a list of integers.
+
+38
+00:02:34,000 --> 00:02:38,000
+We have one fifteen to thirty seven and one hundred.
+
+39
+00:02:38,000 --> 00:02:45,000
+And it is obvious for us what the natural order of these numbers is the same as it is easy for us to
+
+40
+00:02:45,000 --> 00:02:47,000
+understand what a reverse order is.
+
+41
+00:02:48,000 --> 00:02:53,000
+Each list has certain methods that takes object of comparison type as an argument.
+
+42
+00:02:53,000 --> 00:02:59,000
+Let's call short method for our list and reverse order comparator into this method.
+
+43
+00:02:59,000 --> 00:03:05,000
+And after we printed the console, the same collection, we noticed that our collection becomes sorted
+
+44
+00:03:05,000 --> 00:03:06,000
+in the reverse order.
+
+45
+00:03:06,000 --> 00:03:10,000
+But the things that are obvious for us are not obvious for the machines.
+
+46
+00:03:11,000 --> 00:03:16,000
+I believe you understand that for Java it is not obvious by default how to sort numbers.
+
+47
+00:03:17,000 --> 00:03:23,000
+There should be some code written that would tell Java to sort our collection exactly in this way.
+
+48
+00:03:23,000 --> 00:03:27,000
+So let's understand how to describe logic of natural ordering.
+
+49
+00:03:27,000 --> 00:03:34,000
+To explain this, let me open integer type and here we can see that integer implements comparable interface.
+
+50
+00:03:35,000 --> 00:03:36,000
+What is this?
+
+51
+00:03:36,000 --> 00:03:37,000
+Let me open this one.
+
+52
+00:03:38,000 --> 00:03:44,000
+Comparable interface declares the contract only for one method that is compared to method.
+
+53
+00:03:45,000 --> 00:03:50,000
+It takes another object as a method argument and can compare this.
+
+54
+00:03:50,000 --> 00:03:54,000
+The current object with the object that was passed into the method.
+
+55
+00:03:54,000 --> 00:03:59,000
+And you already can see the difference between compare and compare to methods.
+
+56
+00:03:59,000 --> 00:04:07,000
+Compare method takes two arguments compared to takes one argument in more simple words compared the
+
+57
+00:04:07,000 --> 00:04:09,000
+interface tells us something like this.
+
+58
+00:04:10,000 --> 00:04:15,000
+Give me two elements and I will tell you which one is greater than the other one.
+
+59
+00:04:15,000 --> 00:04:18,000
+Whereas comparable interface tells us something like this.
+
+60
+00:04:19,000 --> 00:04:25,000
+Give me an element and I will tell you if it is greater than me, can you feel the difference?
+
+61
+00:04:25,000 --> 00:04:32,000
+Usually comparable interface is implemented by types when we expect that objects of this type will be
+
+62
+00:04:32,000 --> 00:04:39,000
+sorted in containers like we have with the integer type creator of integer class for assorted objects
+
+63
+00:04:39,000 --> 00:04:44,000
+of this type will be compared between each other a lot of times in the future.
+
+64
+00:04:44,000 --> 00:04:46,000
+Let me open integer class again.
+
+65
+00:04:47,000 --> 00:04:50,000
+Let me show you how compared to Method is implemented here.
+
+66
+00:04:50,000 --> 00:04:54,000
+You can see the internal method compare is called here.
+
+67
+00:04:54,000 --> 00:05:01,000
+We possess a current value of the integer object because integer object has value variable and we also
+
+68
+00:05:01,000 --> 00:05:02,000
+pass into value of another.
+
+69
+00:05:03,000 --> 00:05:10,000
+Integer, let me open this campaign method and here we can see that in case the first argument that
+
+70
+00:05:10,000 --> 00:05:17,000
+is X is less than the second argument, that is Y, Z, we return to negative integer minus one.
+
+71
+00:05:17,000 --> 00:05:25,000
+And in case the statement is false, we check if X and Y are equal and is equal, we return zero.
+
+72
+00:05:25,000 --> 00:05:31,000
+And if no, that means X is greater than Y and we are to return positive integer.
+
+73
+00:05:32,000 --> 00:05:33,000
+That is one.
+
+74
+00:05:33,000 --> 00:05:39,000
+To be honest, I still don't know why developers adjudicate decided to write so many texts here.
+
+75
+00:05:39,000 --> 00:05:46,000
+Imagine that in case you have two integers and you need to compare them just right here, X minus Y
+
+76
+00:05:46,000 --> 00:05:47,000
+and that's it.
+
+77
+00:05:47,000 --> 00:05:55,000
+In case X is lower than why we would get negative number in case the equal will get zero, in case X
+
+78
+00:05:55,000 --> 00:05:58,000
+is greater than Y will get positive integer.
+
+79
+00:05:59,000 --> 00:06:03,000
+Sometimes guys from Oracle overcomplicating the things really.
+
+80
+00:06:03,000 --> 00:06:09,000
+But as true professionals, we have to understand this and respect their solutions according to the
+
+81
+00:06:09,000 --> 00:06:13,000
+contract, compared to also returns in value to certain elements.
+
+82
+00:06:14,000 --> 00:06:19,000
+The way how compared to method is implemented in the type is called natural order.
+
+83
+00:06:20,000 --> 00:06:26,000
+So I believe now you understand how Java made the reverse competitor to this required just one positive
+
+84
+00:06:26,000 --> 00:06:30,000
+result of this method into the negative and vice versa.
+
+85
+00:06:30,000 --> 00:06:32,000
+Let's get back to our example.
+
+86
+00:06:32,000 --> 00:06:38,000
+Now, imagine that we want to search elements in natural order in the computer interface.
+
+87
+00:06:38,000 --> 00:06:42,000
+There is also another default method was in the natural order.
+
+88
+00:06:42,000 --> 00:06:45,000
+It looks like that is exactly what we need.
+
+89
+00:06:45,000 --> 00:06:51,000
+You already know what natural order is and you can understand how numbers in our list will be sorted.
+
+90
+00:06:52,000 --> 00:06:57,000
+Things are pretty straightforward with the list of integers, but what will happen with our list of
+
+91
+00:06:57,000 --> 00:06:58,000
+products here?
+
+92
+00:06:58,000 --> 00:07:03,000
+I credit list that contains all products from our online store application.
+
+93
+00:07:03,000 --> 00:07:06,000
+In case you skipped homework, I will explain you.
+
+94
+00:07:07,000 --> 00:07:09,000
+We created our own service.
+
+95
+00:07:09,000 --> 00:07:14,000
+That is the default product management service that implements Singleton parkrun and can be created
+
+96
+00:07:14,000 --> 00:07:15,000
+only in single copy.
+
+97
+00:07:16,000 --> 00:07:18,000
+That's why we call that instance method here.
+
+98
+00:07:18,000 --> 00:07:21,000
+This class contains all products for our app.
+
+99
+00:07:22,000 --> 00:07:26,000
+Products are described with the help of another custom type product type.
+
+100
+00:07:27,000 --> 00:07:29,000
+If you want, you can explore this class in the details.
+
+101
+00:07:29,000 --> 00:07:32,000
+Don't worry, I will leave a link to this class.
+
+102
+00:07:32,000 --> 00:07:38,000
+It is still located in our training project that I am sure you already clone from the GitHub.
+
+103
+00:07:39,000 --> 00:07:43,000
+So when we fetched all products, we bring them to the console.
+
+104
+00:07:43,000 --> 00:07:45,000
+Each product from the new line.
+
+105
+00:07:45,000 --> 00:07:47,000
+I created custom method for that.
+
+106
+00:07:48,000 --> 00:07:50,000
+Nothing special just for each loop.
+
+107
+00:07:50,000 --> 00:07:51,000
+That's it.
+
+108
+00:07:52,000 --> 00:07:55,000
+Please don't pay attention to this wild card in the master signature.
+
+109
+00:07:56,000 --> 00:07:58,000
+We will talk about that when we return.
+
+110
+00:07:58,000 --> 00:07:59,000
+Generics topic.
+
+111
+00:07:59,000 --> 00:08:03,000
+What happens when we try to source products in natural order?
+
+112
+00:08:03,000 --> 00:08:05,000
+We see a compilation error.
+
+113
+00:08:05,000 --> 00:08:06,000
+Why?
+
+114
+00:08:06,000 --> 00:08:10,000
+Because our custom product type does not implement comparable interface.
+
+115
+00:08:11,000 --> 00:08:14,000
+So what we have to do now, we have two options.
+
+116
+00:08:14,000 --> 00:08:19,000
+Either we have to implement comparable interface and our product type or we have to implement our own
+
+117
+00:08:19,000 --> 00:08:20,000
+comparator.
+
+118
+00:08:20,000 --> 00:08:23,000
+That would contain the logic to compare elements.
+
+119
+00:08:23,000 --> 00:08:27,000
+Let me show you all these options to save the time.
+
+120
+00:08:27,000 --> 00:08:33,000
+During the video lesson, I created a product type that implements comparable interface and by default
+
+121
+00:08:33,000 --> 00:08:34,000
+we source products by idee.
+
+122
+00:08:35,000 --> 00:08:42,000
+To implement comparable interface, I added one more interface here after implements keyboards, you're
+
+123
+00:08:42,000 --> 00:08:44,000
+already familiar how to use generics.
+
+124
+00:08:44,000 --> 00:08:46,000
+Wasleys she has a similar thing.
+
+125
+00:08:47,000 --> 00:08:53,000
+I specify product type here in Diamond Operator to tell that our comparable implementation should compare
+
+126
+00:08:53,000 --> 00:08:54,000
+product type.
+
+127
+00:08:54,000 --> 00:09:01,000
+The generic usage allows me to get product type in parameters here in compared to method instead of
+
+128
+00:09:01,000 --> 00:09:04,000
+pure object and Tussaud elements by.
+
+129
+00:09:04,000 --> 00:09:06,000
+I just perform subtraction here.
+
+130
+00:09:06,000 --> 00:09:12,000
+We already reviewed on previous examples in which cases I return positive, negative or zero here.
+
+131
+00:09:13,000 --> 00:09:19,000
+That's why I suggest moving further now when we have comparable product, let's create a few objects
+
+132
+00:09:19,000 --> 00:09:22,000
+of comparable product type and add them to the list.
+
+133
+00:09:23,000 --> 00:09:28,000
+In the real app, probably you would extend product interface from comparable interface or you would
+
+134
+00:09:28,000 --> 00:09:34,000
+implement some absurd product type where you would implement comparable interface and you would use
+
+135
+00:09:34,000 --> 00:09:36,000
+that level of abstraction across your all application.
+
+136
+00:09:37,000 --> 00:09:39,000
+That just a few ideas to think about.
+
+137
+00:09:40,000 --> 00:09:45,000
+Now, in case we would support a comparable product, we would have all our products sorted according
+
+138
+00:09:45,000 --> 00:09:46,000
+to ideas.
+
+139
+00:09:47,000 --> 00:09:51,000
+And as you can see, it doesn't matter in which order we added our products to the list.
+
+140
+00:09:52,000 --> 00:09:58,000
+But what if we want to sort my product name and natural order doesn't work for us?
+
+141
+00:09:58,000 --> 00:10:01,000
+In this case, we have to implement our competitor.
+
+142
+00:10:02,000 --> 00:10:10,000
+We have four ways to implement comparator Zaya LeClaire anonymous class, create separate class, write
+
+143
+00:10:10,000 --> 00:10:13,000
+lambda expression, use method reference.
+
+144
+00:10:14,000 --> 00:10:19,000
+Then we are going to review first two options and the rest will learn in the separate lessons.
+
+145
+00:10:19,000 --> 00:10:25,000
+When we will talk about functional programming in Java, we have our list of products where products
+
+146
+00:10:25,000 --> 00:10:28,000
+don't implement comparable interface.
+
+147
+00:10:28,000 --> 00:10:30,000
+Let me use that one for sourcing.
+
+148
+00:10:31,000 --> 00:10:38,000
+I write a new comparator and specify product type in Diament operator to tell Java compilers, and this
+
+149
+00:10:38,000 --> 00:10:43,000
+comparator will work with Prototype and after that I am going to declare anonymous class.
+
+150
+00:10:44,000 --> 00:10:50,000
+And in case you missed my Java lesson about anonymous classes, please check that it will help you for
+
+151
+00:10:50,000 --> 00:10:55,000
+understanding of anonymous classes and here give implementation for compare method.
+
+152
+00:10:56,000 --> 00:10:59,000
+The second option is to implement separate class.
+
+153
+00:10:59,000 --> 00:11:05,000
+You can create separate file for that one, but for the sake of the demo, I will declare another class
+
+154
+00:11:05,000 --> 00:11:09,000
+in the same file here to keep all code examples from the lesson in one file.
+
+155
+00:11:10,000 --> 00:11:15,000
+So I have product name comparator class that implements comparator interface.
+
+156
+00:11:16,000 --> 00:11:19,000
+The implementation is the same as we have in our anonymous class.
+
+157
+00:11:20,000 --> 00:11:24,000
+I can source my products by passing the reference to the object of my competitor.
+
+158
+00:11:25,000 --> 00:11:28,000
+So there's two ways to source elements are similar.
+
+159
+00:11:28,000 --> 00:11:30,000
+It is up to you which one to choose.
+
+160
+00:11:31,000 --> 00:11:36,000
+I'm going to give you a task where you might practice in the implementation of comparator interface.
+
+161
+00:11:37,000 --> 00:11:43,000
+If you want me to answer what is better comparator or comparable, I wouldn't answer that question.
+
+162
+00:11:44,000 --> 00:11:48,000
+Using off any of these interfaces depends on the real case.
+
+163
+00:11:48,000 --> 00:11:54,000
+For example, you need to search elements by specific field in one method, then compare to usage would
+
+164
+00:11:54,000 --> 00:12:00,000
+be justified in case you don't have possibility to rewrite the type and implement comparable there.
+
+165
+00:12:01,000 --> 00:12:03,000
+You also have to use comparator in this case.
+
+166
+00:12:04,000 --> 00:12:09,000
+But if you know that objects of your type will be sorted on a regular basis during the creation of the
+
+167
+00:12:09,000 --> 00:12:13,000
+new type, you can consider implementation of comparable interface.
+
+168
+00:12:13,000 --> 00:12:14,000
+Does it make sense?
+
+169
+00:12:15,000 --> 00:12:19,000
+Before we proceed, I want to finish overview of assets in Comparator.
+
+170
+00:12:19,000 --> 00:12:24,000
+We have overloaded them comparing methods which I would say not used very often.
+
+171
+00:12:25,000 --> 00:12:29,000
+Originally, this method is built to great chain for comparison logic.
+
+172
+00:12:29,000 --> 00:12:34,000
+In the case, elements are equal, but to be honest, you can write the same logic in one method.
+
+173
+00:12:35,000 --> 00:12:40,000
+But it is also worth to mention that such architecture would allow you to be more flexible in describing
+
+174
+00:12:40,000 --> 00:12:45,000
+your comparison logic and to use different chain of comparisons in different situations.
+
+175
+00:12:46,000 --> 00:12:52,000
+While this brings a lot of flexibility, I can't come up with an example right now or any business case
+
+176
+00:12:52,000 --> 00:12:54,000
+where this flexibility will be needed.
+
+177
+00:12:55,000 --> 00:13:01,000
+We also hear no first and no last message that returned competitors with a specific logic for certain
+
+178
+00:13:01,000 --> 00:13:05,000
+new values and here also different variations of compare and method.
+
+179
+00:13:05,000 --> 00:13:07,000
+Those are pretty interesting.
+
+180
+00:13:07,000 --> 00:13:13,000
+For example, we can call comparing method and parse functions that will extract the field that we want
+
+181
+00:13:13,000 --> 00:13:20,000
+to use for sorting or extract the field and override natural ordering for it by providing another function
+
+182
+00:13:20,000 --> 00:13:21,000
+in return.
+
+183
+00:13:21,000 --> 00:13:24,000
+We will get comparators that we can use to search elements.
+
+184
+00:13:25,000 --> 00:13:31,000
+Review of these methods lies outside of our today's agenda, but we will definitely talk about this
+
+185
+00:13:31,000 --> 00:13:33,000
+when we agree on functional programming topic.
+
+186
+00:13:34,000 --> 00:13:39,000
+The last thing for the is that I want to discuss is to answer one of your potential questions.
+
+187
+00:13:40,000 --> 00:13:41,000
+Take into account this video.
+
+188
+00:13:41,000 --> 00:13:47,000
+Of course, I always try to predict what questions you might have, but in case I didn't answer all
+
+189
+00:13:47,000 --> 00:13:49,000
+your questions in the media, feel free to pose questions.
+
+190
+00:13:49,000 --> 00:13:55,000
+And the easiest lesson probably you are wondering how function that takes on the two arguments.
+
+191
+00:13:55,000 --> 00:13:59,000
+That is our campaign method, how it concerns all elements.
+
+192
+00:14:00,000 --> 00:14:03,000
+That is because algorithms with the name quicksort is applied.
+
+193
+00:14:04,000 --> 00:14:09,000
+This is not the course about algorithms, but I believe for the general understanding it will be useful
+
+194
+00:14:09,000 --> 00:14:12,000
+for you to know how quicksort algorithm works.
+
+195
+00:14:12,000 --> 00:14:16,000
+As I said, I'm not going to dive deep into the details.
+
+196
+00:14:16,000 --> 00:14:22,000
+Someday I will create course about algorithms and we are going to learn all algorithms in a nutshell.
+
+197
+00:14:23,000 --> 00:14:26,000
+But right now, I want you to look at this GIF image.
+
+198
+00:14:26,000 --> 00:14:30,000
+It explains exactly how quicksort algorithm works.
+
+199
+00:14:31,000 --> 00:14:32,000
+Quicksort algorithm.
+
+200
+00:14:32,000 --> 00:14:37,000
+It is still a commonly used algorithm for searching when implemented well.
+
+201
+00:14:37,000 --> 00:14:41,000
+It can be about two or three times faster than its main competitors.
+
+202
+00:14:41,000 --> 00:14:43,000
+Match, source and heat source.
+
+203
+00:14:44,000 --> 00:14:51,000
+The algorithm finds pivot element and after that split all elements into two separate, comparing each
+
+204
+00:14:51,000 --> 00:14:56,000
+element with belittlement algorithm source element by telling whether a particular element less or greater
+
+205
+00:14:56,000 --> 00:14:57,000
+than pivot.
+
+206
+00:14:58,000 --> 00:15:03,000
+As we go over each element, we constantly compare two elements and swapping them.
+
+207
+00:15:04,000 --> 00:15:07,000
+That's why Java needs methods that can compare to elements.
+
+208
+00:15:08,000 --> 00:15:14,000
+If you would open source code of the source method, you would discover a compromise that will be called
+
+209
+00:15:14,000 --> 00:15:17,000
+multiple times until all elements will be sorted.
+
+210
+00:15:17,000 --> 00:15:23,000
+Now, I believe you understand why we need to pass the parameters into our campaign method.
+
+211
+00:15:23,000 --> 00:15:26,000
+We did a great job today and learned a lot of things.
+
+212
+00:15:26,000 --> 00:15:29,000
+Let's recap what we have learned today.
+
+213
+00:15:29,000 --> 00:15:32,000
+Today we learned what comparator is.
+
+214
+00:15:32,000 --> 00:15:35,000
+We also learned what a comparable interface is.
+
+215
+00:15:35,000 --> 00:15:41,000
+We learned how to source elements in list by using natural and reverse ordering of elements.
+
+216
+00:15:41,000 --> 00:15:47,000
+Now, you know what the difference is between the compare and compare to methods and real examples we
+
+217
+00:15:47,000 --> 00:15:51,000
+learned when we need to use comparator and when we need to use comparable.
+
+218
+00:15:52,000 --> 00:15:57,000
+We created our custom comparable product and created comparison for existing type.
+
+219
+00:15:57,000 --> 00:16:00,000
+And at the end of the lesson we learned quicksort algorithm.
+
+220
+00:16:01,000 --> 00:16:03,000
+Now I suggest reviewing your homework.
+
+221
+00:16:04,000 --> 00:16:09,000
+And your homework, you have to implement comparison in the separate file that would search products
+
+222
+00:16:09,000 --> 00:16:13,000
+by category names, then by price and then by product name.
+
+223
+00:16:13,000 --> 00:16:19,000
+Here you may find links to the product interface type and implementation of product interface.
+
+224
+00:16:19,000 --> 00:16:25,000
+Also here you can see a list of products that you can use during the testing and believe that you will
+
+225
+00:16:25,000 --> 00:16:27,000
+be able to accomplish this task easily.
+
+226
+00:16:28,000 --> 00:16:29,000
+I believe in you.
+
+227
+00:16:30,000 --> 00:16:32,000
+That's all what I have for you for today.
+
+228
+00:16:32,000 --> 00:16:36,000
+Thanks a lot for your attention and see you in the next lesson.
+

19 - Java Collections Framework/008 Homework-Solution-Custom-Comparator.url

@@ -0,0 +1,2 @@
+[InternetShortcut]
+URL=https://github.com/AndriiPiatakha/learnit_java_core/blob/master/src/com/itbulls/learnit/javacore/jcf/hw/onlinestore/withlist/utils/comparators/CustomProductComparator.java

19 - Java Collections Framework/008 Homework.url

@@ -0,0 +1,2 @@
+[InternetShortcut]
+URL=https://docs.google.com/document/d/1senXk6JLFWsVQnJT5si_QgodHkXMFgIIPK447rgXSN0/edit?usp=sharing

19 - Java Collections Framework/008 Source-code-of-the-example-used-in-the-lesson.url

@@ -0,0 +1,2 @@
+[InternetShortcut]
+URL=https://github.com/AndriiPiatakha/learnit_java_core/blob/master/src/com/itbulls/learnit/javacore/jcf/sorting/ComparisonDemo.java

19 - Java Collections Framework/010 Homework-Solution-Custom-Iterator-and-ListIterator.url

@@ -0,0 +1,2 @@
+[InternetShortcut]
+URL=https://github.com/AndriiPiatakha/learnit_java_core/tree/master/src/com/itbulls/learnit/javacore/jcf/collections/list/hw

19 - Java Collections Framework/010 Homework.url

@@ -0,0 +1,2 @@
+[InternetShortcut]
+URL=https://docs.google.com/document/d/1EAQRwHR1HbWt95T3FtS9EOdQsIc_3nZFYUvc6Qv4frQ/edit?usp=sharing

19 - Java Collections Framework/010 Iterable, Iterator & ListIterator_en.srt

@@ -0,0 +1,1080 @@
+1
+00:00:06,000 --> 00:00:06,000
+Hello, Jim.
+
+2
+00:00:06,000 --> 00:00:11,000
+In this lesson, we are going to talk about what iterable and iterator interfaces are.
+
+3
+00:00:11,000 --> 00:00:17,000
+We would investigate source code of these two interfaces and also will answer what is the role of these
+
+4
+00:00:17,000 --> 00:00:19,000
+two interfaces in Java collections framework.
+
+5
+00:00:20,000 --> 00:00:23,000
+After this lesson, you will never confuse these two interfaces.
+
+6
+00:00:23,000 --> 00:00:26,000
+We are going to learn three types of iterator.
+
+7
+00:00:26,000 --> 00:00:32,000
+And at the end of the lesson, I also want to demo what least Iterator is and how it is different from
+
+8
+00:00:32,000 --> 00:00:33,000
+Iterator.
+
+9
+00:00:33,000 --> 00:00:34,000
+Let's start.
+
+10
+00:00:34,000 --> 00:00:40,000
+I believe you remember that first time when we looked at collection interface, we found that collection
+
+11
+00:00:40,000 --> 00:00:43,000
+interface is extended from iterable interface.
+
+12
+00:00:43,000 --> 00:00:50,000
+You remember that as you can see on this class diagram, iterable interface has only one method iterator.
+
+13
+00:00:51,000 --> 00:00:53,000
+This method should return object of iterate type.
+
+14
+00:00:54,000 --> 00:00:59,000
+That means that each implementation of collection interfacing Java should have iterator.
+
+15
+00:00:59,000 --> 00:01:03,000
+I believe that is all what we can say about iterable interface.
+
+16
+00:01:03,000 --> 00:01:10,000
+This interface is to tell that I'm the type that has iterator more interesting to talk about what an
+
+17
+00:01:10,000 --> 00:01:17,000
+iterator is and to answer this question, I suggest reviewing source code of iterator type in eclipse
+
+18
+00:01:17,000 --> 00:01:18,000
+in few words.
+
+19
+00:01:18,000 --> 00:01:22,000
+Iterator is a type that can go over each element in a container.
+
+20
+00:01:22,000 --> 00:01:23,000
+That's it.
+
+21
+00:01:23,000 --> 00:01:27,000
+You might be wondering, is it really so hard and separate type is needed?
+
+22
+00:01:28,000 --> 00:01:31,000
+It is not so hard, but imagine two simple cases.
+
+23
+00:01:31,000 --> 00:01:34,000
+You have array lists and linked list.
+
+24
+00:01:34,000 --> 00:01:39,000
+In our list we are together elements from the array by the indexes in the linked list.
+
+25
+00:01:39,000 --> 00:01:44,000
+We have to get the reference to the next node from each node to iterate over elements.
+
+26
+00:01:44,000 --> 00:01:50,000
+Can you see that the way how to iterate over each element, even in these two collections, is completely
+
+27
+00:01:50,000 --> 00:01:51,000
+different?
+
+28
+00:01:52,000 --> 00:01:58,000
+That's exactly the reason why we need to come up with some abstract type like Iterator to set the interface
+
+29
+00:01:58,000 --> 00:02:02,000
+that should be implemented by specific implementations of collection interface.
+
+30
+00:02:02,000 --> 00:02:05,000
+So let's sum up what Iterator is.
+
+31
+00:02:06,000 --> 00:02:12,000
+Iterator is an interface that allows access to the elements in container and navigation in collection,
+
+32
+00:02:12,000 --> 00:02:19,000
+including iteration or in other words, looping over each element in any collection without knowing
+
+33
+00:02:19,000 --> 00:02:22,000
+the details of implementation of specific collection.
+
+34
+00:02:23,000 --> 00:02:30,000
+Now we are going to run the interface of iterate the type it has to abstract and two default methods.
+
+35
+00:02:31,000 --> 00:02:33,000
+Let me explain what each of these methods is about.
+
+36
+00:02:34,000 --> 00:02:37,000
+Has an X method returns true or false?
+
+37
+00:02:37,000 --> 00:02:43,000
+It tells us whether the next element is present will use this method in loops to check if it was to
+
+38
+00:02:43,000 --> 00:02:49,000
+go on with our loop or we reached the end of the collection and we have to break the loop.
+
+39
+00:02:50,000 --> 00:02:53,000
+Next method returns the next element in connection.
+
+40
+00:02:53,000 --> 00:02:54,000
+Be careful.
+
+41
+00:02:54,000 --> 00:03:01,000
+This method may throw no such element exception and interrupt your program execution in case you called
+
+42
+00:03:01,000 --> 00:03:02,000
+next method.
+
+43
+00:03:02,000 --> 00:03:04,000
+But there are no any elements there.
+
+44
+00:03:04,000 --> 00:03:07,000
+That is a contract of the Iterator interface.
+
+45
+00:03:07,000 --> 00:03:09,000
+We can do nothing about that.
+
+46
+00:03:09,000 --> 00:03:16,000
+That's why before calling next method, we have to always call has next method remove method supposed
+
+47
+00:03:16,000 --> 00:03:21,000
+to remove the last element returned by next method and now attention.
+
+48
+00:03:21,000 --> 00:03:25,000
+This method can be called only once after each next method call.
+
+49
+00:03:25,000 --> 00:03:31,000
+We can't call two times next method and after that call two times remove method.
+
+50
+00:03:31,000 --> 00:03:37,000
+That is the way how Iterator should work in case you would call remove method without calling next method
+
+51
+00:03:37,000 --> 00:03:42,000
+or we'll call remove two times in a row in your program, your program will be stopped with illegal
+
+52
+00:03:42,000 --> 00:03:43,000
+state exception.
+
+53
+00:03:44,000 --> 00:03:46,000
+But there is more interesting thing here.
+
+54
+00:03:46,000 --> 00:03:50,000
+By default, remove method throws and support the separation exception.
+
+55
+00:03:50,000 --> 00:03:56,000
+That means that in case we would call this method, our program will be stopped with the exceptional
+
+56
+00:03:56,000 --> 00:03:56,000
+situation.
+
+57
+00:03:57,000 --> 00:04:01,000
+Now I'm going to say not only my opinion, but opinion of different engineers too.
+
+58
+00:04:02,000 --> 00:04:06,000
+It is senseless to declare method in the interface that is not needed.
+
+59
+00:04:06,000 --> 00:04:07,000
+Yes, exactly.
+
+60
+00:04:08,000 --> 00:04:14,000
+This exception here and support the separation exception tells us that by default this method is not
+
+61
+00:04:14,000 --> 00:04:15,000
+supported.
+
+62
+00:04:15,000 --> 00:04:18,000
+Don't do that during the implementation of your interfaces.
+
+63
+00:04:19,000 --> 00:04:19,000
+Why?
+
+64
+00:04:20,000 --> 00:04:21,000
+Let me explain here.
+
+65
+00:04:21,000 --> 00:04:24,000
+We can see a violation of one of the solid principles.
+
+66
+00:04:25,000 --> 00:04:29,000
+Can you guess what solid principle is violated in the Iterator interface?
+
+67
+00:04:30,000 --> 00:04:31,000
+Exactly.
+
+68
+00:04:31,000 --> 00:04:34,000
+High principle interface aggregation principle.
+
+69
+00:04:34,000 --> 00:04:39,000
+According to this principle, no client should be forced to depend on methods it doesn't use.
+
+70
+00:04:40,000 --> 00:04:46,000
+Originally, according to the documentation, Iterator type was created to iterate over elements, but
+
+71
+00:04:46,000 --> 00:04:47,000
+not to remove them.
+
+72
+00:04:47,000 --> 00:04:50,000
+How would I recommend implementing this?
+
+73
+00:04:50,000 --> 00:04:56,000
+I would create something like removable iterator that extends iterate type and would let client of my
+
+74
+00:04:56,000 --> 00:05:03,000
+code to decide whether they need to remove method or no, because right now each implementation of Iterator.
+
+75
+00:05:03,000 --> 00:05:10,000
+Interface has removed MassArt, even if it is not a that this is default MassArt and there is no need
+
+76
+00:05:10,000 --> 00:05:10,000
+to override it.
+
+77
+00:05:11,000 --> 00:05:18,000
+But this does not make life of engineers easier because we still can call, remove by mistake and rely
+
+78
+00:05:18,000 --> 00:05:21,000
+on the fact that this behavior should be supported in iterator.
+
+79
+00:05:22,000 --> 00:05:24,000
+Now, you know that there is an exception here.
+
+80
+00:05:25,000 --> 00:05:30,000
+The other side of this violation is that in the case in Java collections framework, engineers would
+
+81
+00:05:30,000 --> 00:05:35,000
+follow all or P principles, including interface aggregation principle.
+
+82
+00:05:35,000 --> 00:05:42,000
+There would be big bank of interfaces that is hard to learn and hard to remember and even harder to
+
+83
+00:05:42,000 --> 00:05:42,000
+maintain.
+
+84
+00:05:43,000 --> 00:05:49,000
+So as you can see, programming like everything else in our lives is all about tradeoffs and compromises.
+
+85
+00:05:50,000 --> 00:05:56,000
+The last but not the least massaged here in Interactor interface is for each remaining, this matter
+
+86
+00:05:56,000 --> 00:06:01,000
+takes function that should be applied for each element that remains in the container.
+
+87
+00:06:01,000 --> 00:06:07,000
+The usage of this message requires knowledge of functional programming in Java and no interfaces from
+
+88
+00:06:07,000 --> 00:06:09,000
+the Java Wattyl function package.
+
+89
+00:06:10,000 --> 00:06:13,000
+That's why today will not Damul work of this method.
+
+90
+00:06:13,000 --> 00:06:16,000
+But we will damage it in the lesson about functional programming.
+
+91
+00:06:17,000 --> 00:06:23,000
+OK, now when we know iterate the interface, I suggest learning how it works and to practice a bit.
+
+92
+00:06:24,000 --> 00:06:28,000
+And I would like to visualize the way how Massaponax and remove works.
+
+93
+00:06:28,000 --> 00:06:30,000
+Let's take a look at this slide.
+
+94
+00:06:30,000 --> 00:06:36,000
+I want you to imagine that Iterator works like a cursor, namely at the beginning.
+
+95
+00:06:36,000 --> 00:06:38,000
+It stands right before the first element.
+
+96
+00:06:39,000 --> 00:06:43,000
+When we call next method, it returns the next element to us.
+
+97
+00:06:43,000 --> 00:06:49,000
+And now cursor stands between the first and the second element in case we call next method one more
+
+98
+00:06:49,000 --> 00:06:55,000
+time cursor is moved to the position between second and the third element like you see on the slide.
+
+99
+00:06:56,000 --> 00:07:02,000
+Now, when we call remove method Iterator works as a backspace key on the Windows machines, it removes
+
+100
+00:07:02,000 --> 00:07:05,000
+elements that stands right before the cursor.
+
+101
+00:07:05,000 --> 00:07:06,000
+Does it make sense?
+
+102
+00:07:07,000 --> 00:07:08,000
+Now let's get back to Eclipse.
+
+103
+00:07:09,000 --> 00:07:15,000
+For the sake of the drama, I created this demo file to practice a bit with Iterator, let me run this
+
+104
+00:07:15,000 --> 00:07:18,000
+program and walk you through the different cases that are listed here.
+
+105
+00:07:19,000 --> 00:07:24,000
+At the beginning, I created the list of integers to play with, you already know this construction,
+
+106
+00:07:25,000 --> 00:07:27,000
+so there is nothing special for you here.
+
+107
+00:07:27,000 --> 00:07:30,000
+Now, let's iterate over each element in container.
+
+108
+00:07:31,000 --> 00:07:37,000
+I call iterate a method on our list that returns iterator object parametrized by integer type.
+
+109
+00:07:37,000 --> 00:07:44,000
+This means that when I will call next Masset iterate, I will reach an object of type integer like it
+
+110
+00:07:44,000 --> 00:07:49,000
+specified here in Diamond Operator, but not the object of type object.
+
+111
+00:07:49,000 --> 00:07:55,000
+After that we have while loop and I check in condition statement here was an iterator has an extra element
+
+112
+00:07:55,000 --> 00:07:56,000
+or no.
+
+113
+00:07:56,000 --> 00:08:03,000
+And if yes I want to print it to cancel next match it returns me means a reference to the next element
+
+114
+00:08:03,000 --> 00:08:04,000
+in my container.
+
+115
+00:08:04,000 --> 00:08:06,000
+Is everything clear here.
+
+116
+00:08:06,000 --> 00:08:10,000
+Haubert is the next example is more like practical type.
+
+117
+00:08:11,000 --> 00:08:17,000
+Some of my students that I taught offline feel concerned that they can use the same iterator once we
+
+118
+00:08:17,000 --> 00:08:19,000
+iterate it over all elements.
+
+119
+00:08:19,000 --> 00:08:26,000
+So after the previous loop, our iterator cursor is at the end of the container and has an X method
+
+120
+00:08:26,000 --> 00:08:27,000
+will return false.
+
+121
+00:08:27,000 --> 00:08:31,000
+That is exactly the reason why we see this console output here.
+
+122
+00:08:32,000 --> 00:08:33,000
+But what to do now?
+
+123
+00:08:33,000 --> 00:08:40,000
+We can use the same variable and initialize it with a new iterator object because no message to reset
+
+124
+00:08:40,000 --> 00:08:44,000
+courser obliterated back again to the beginning like we did here.
+
+125
+00:08:45,000 --> 00:08:46,000
+So that is fine.
+
+126
+00:08:47,000 --> 00:08:49,000
+Now I want to them how remove method works.
+
+127
+00:08:50,000 --> 00:08:56,000
+Let's remove all even numbers from our container we call next method to get the element from the container.
+
+128
+00:08:57,000 --> 00:09:02,000
+After that, we check whether this number is A1 and if yes, then we remove it.
+
+129
+00:09:02,000 --> 00:09:06,000
+You can see that I don't violate the rules of remove method usage.
+
+130
+00:09:07,000 --> 00:09:10,000
+I call remove method only after I called next method.
+
+131
+00:09:11,000 --> 00:09:14,000
+And also there are no multiple locations of remove method.
+
+132
+00:09:15,000 --> 00:09:22,000
+You also can notice that iterator that is implemented in at least overwrites remove Masset and doesn't
+
+133
+00:09:22,000 --> 00:09:27,000
+throw and supports the separation exception like the full implementation of Remove Massud does.
+
+134
+00:09:28,000 --> 00:09:33,000
+Now, if you are not familiar with the exception topic yet, let me show you an example.
+
+135
+00:09:33,000 --> 00:09:36,000
+What exception means and how the writer may throw exceptions.
+
+136
+00:09:37,000 --> 00:09:43,000
+Lattman comments these lines of code I initialised again my iterative variable with the new iterator
+
+137
+00:09:43,000 --> 00:09:44,000
+object.
+
+138
+00:09:44,000 --> 00:09:47,000
+After that I call Remove Masset without calling.
+
+139
+00:09:47,000 --> 00:09:48,000
+Next Masset.
+
+140
+00:09:48,000 --> 00:09:50,000
+Let me run my program now.
+
+141
+00:09:50,000 --> 00:09:53,000
+And here we can see illegal state exception.
+
+142
+00:09:53,000 --> 00:09:58,000
+The same exceptions will be thrown in case we would call remove Massud two times in a row.
+
+143
+00:09:59,000 --> 00:10:04,000
+That is something what you have to remember at the end of the lesson I will share with your home task
+
+144
+00:10:04,000 --> 00:10:09,000
+where you will have opportunity to practice your skills in writing your custom iterators.
+
+145
+00:10:09,000 --> 00:10:14,000
+Let me comment these lines to be able to execute code that is written after this one.
+
+146
+00:10:15,000 --> 00:10:21,000
+Let me also show one more important exception that might be thrown by Iterator that is concurrent modification,
+
+147
+00:10:21,000 --> 00:10:25,000
+exception and uncommon these lines of code and will damage to you.
+
+148
+00:10:26,000 --> 00:10:32,000
+Imagine that we created Iterator and when we started iteration, we removed elements from the container,
+
+149
+00:10:33,000 --> 00:10:37,000
+but not with the help of Iterator, but just by using the removed method of our list.
+
+150
+00:10:38,000 --> 00:10:39,000
+This is just an example.
+
+151
+00:10:39,000 --> 00:10:45,000
+In real life, it might happen that you created an iterator on the list that is shared between different
+
+152
+00:10:45,000 --> 00:10:50,000
+threats of execution and somebody in another thread did some modifications to your list.
+
+153
+00:10:51,000 --> 00:10:56,000
+And after we would call next method, we would see concurrent modification exception.
+
+154
+00:10:56,000 --> 00:11:01,000
+That means somebody modified the collection after Iterator had been created.
+
+155
+00:11:02,000 --> 00:11:07,000
+Iterate an object, noticed that and want to let us know that collections that we are iterating over
+
+156
+00:11:07,000 --> 00:11:09,000
+is not up to date.
+
+157
+00:11:09,000 --> 00:11:15,000
+And that information about elements that I will read with the help of this iterator is not relevant
+
+158
+00:11:15,000 --> 00:11:15,000
+anymore.
+
+159
+00:11:16,000 --> 00:11:19,000
+This type of iterator is called fail fast iterator.
+
+160
+00:11:20,000 --> 00:11:25,000
+That is default implementation of iterators in majority of collection implementations that are not developed
+
+161
+00:11:25,000 --> 00:11:27,000
+to be used in multithreaded environment.
+
+162
+00:11:28,000 --> 00:11:34,000
+What to do in this case, in case you have iterate to make sure there is no other place in your code
+
+163
+00:11:34,000 --> 00:11:36,000
+where you modify the same collection simultaneously.
+
+164
+00:11:37,000 --> 00:11:43,000
+If you do modify collections from different sets of execution, then you need failsafe iterator.
+
+165
+00:11:43,000 --> 00:11:47,000
+That is a second type of iterator that usually called failsafe.
+
+166
+00:11:48,000 --> 00:11:53,000
+Let me Corman's the concurrent modification demo code to be able to proceed with the next one and I
+
+167
+00:11:53,000 --> 00:11:55,000
+ran the program again.
+
+168
+00:11:55,000 --> 00:12:02,000
+Usually thread safe implementation of collections also implements failsafe iterator to explain in short
+
+169
+00:12:02,000 --> 00:12:04,000
+how it works without going deep into the details.
+
+170
+00:12:05,000 --> 00:12:11,000
+Failsafe Iterate that makes a copy of the internal data structure and iterate over the corporate data
+
+171
+00:12:11,000 --> 00:12:11,000
+structure.
+
+172
+00:12:12,000 --> 00:12:17,000
+And a structural modification done to the Iterator doesn't affect the copied data structure.
+
+173
+00:12:17,000 --> 00:12:20,000
+So original data structure is changed.
+
+174
+00:12:21,000 --> 00:12:26,000
+This type of iterator creates a snapshot and iterate over elements in this snapshot.
+
+175
+00:12:27,000 --> 00:12:30,000
+The drawback of such iterator type is obvious.
+
+176
+00:12:30,000 --> 00:12:36,000
+In some cases, you may not receive latest and up to date version of elements in case collection is
+
+177
+00:12:36,000 --> 00:12:38,000
+modified from the different threats.
+
+178
+00:12:39,000 --> 00:12:41,000
+But sometimes it might be not critical for you.
+
+179
+00:12:42,000 --> 00:12:48,000
+Here we have thread safe list implementation copy and write a list I initialize.
+
+180
+00:12:48,000 --> 00:12:50,000
+It was elements that are in our integers list.
+
+181
+00:12:51,000 --> 00:12:55,000
+I create iterator interface of the that is the same everywhere.
+
+182
+00:12:56,000 --> 00:12:58,000
+That's why I use the same variables that I had created.
+
+183
+00:12:59,000 --> 00:13:05,000
+As I already mentioned, failsafe iterators creates a snapshot of the container to prove this.
+
+184
+00:13:05,000 --> 00:13:13,000
+Here I add another integer to this container and now when I iterate over elements and as in previous
+
+185
+00:13:13,000 --> 00:13:15,000
+example, I remove elements from collection.
+
+186
+00:13:15,000 --> 00:13:19,000
+Without Iterator, I still bring elements from the container to the console.
+
+187
+00:13:20,000 --> 00:13:23,000
+But why not print the collection to console?
+
+188
+00:13:23,000 --> 00:13:27,000
+It has only one number that we added after iterator creation.
+
+189
+00:13:27,000 --> 00:13:33,000
+This proves that Iterator creates a snapshot with elements, and this snapshot is not updated as we
+
+190
+00:13:33,000 --> 00:13:36,000
+update collection after creation of Iterator.
+
+191
+00:13:37,000 --> 00:13:41,000
+There is also a third type of iterator that is called weakly consistent.
+
+192
+00:13:42,000 --> 00:13:48,000
+It is called so because this type of iterator can reflect some, but not necessarily all of the changes
+
+193
+00:13:48,000 --> 00:13:52,000
+that have been made to the collection since Iterator is created.
+
+194
+00:13:52,000 --> 00:13:53,000
+Let me show you this.
+
+195
+00:13:53,000 --> 00:14:00,000
+I declare a new variable of collection type parametrized with integer type an aggregate object of concurrent
+
+196
+00:14:00,000 --> 00:14:01,000
+linked deck.
+
+197
+00:14:01,000 --> 00:14:05,000
+This collection implementation has weekly consistent Iterator implementation.
+
+198
+00:14:06,000 --> 00:14:11,000
+I create an iterator and now attention similar to the previous example.
+
+199
+00:14:11,000 --> 00:14:14,000
+I add new integer here and now.
+
+200
+00:14:14,000 --> 00:14:20,000
+When I'm iterating over each element, I can see that new integer already was taken into account here.
+
+201
+00:14:21,000 --> 00:14:26,000
+But as it is said in the documentation, there is no guarantee that all updates to the collection will
+
+202
+00:14:26,000 --> 00:14:31,000
+be taken into account by the moment Iterator would reach the specific element.
+
+203
+00:14:31,000 --> 00:14:34,000
+I understand now what is really consistent iterator.
+
+204
+00:14:35,000 --> 00:14:39,000
+So now we may say that we learned three types of the iterator.
+
+205
+00:14:39,000 --> 00:14:44,000
+The last thing that I would like to learn with you today is a list iterator.
+
+206
+00:14:44,000 --> 00:14:46,000
+Let's look at this interface.
+
+207
+00:14:46,000 --> 00:14:51,000
+The first thing that you can see is that list rate that extends iterate the interface.
+
+208
+00:14:52,000 --> 00:14:58,000
+The main feature that is introduced list, right, is to iterate over elements in the reverse direction.
+
+209
+00:14:58,000 --> 00:15:04,000
+If Iterator can go over elements from the beginning to the end, the list rate that can go from the
+
+210
+00:15:04,000 --> 00:15:06,000
+end to the beginning.
+
+211
+00:15:06,000 --> 00:15:12,000
+It also declares mass that absent in iterator interface, Zaya has Hesperus.
+
+212
+00:15:12,000 --> 00:15:14,000
+It is similar to his next.
+
+213
+00:15:14,000 --> 00:15:21,000
+But check if there any element in another direction, previs returns the reference to the previous element
+
+214
+00:15:21,000 --> 00:15:29,000
+in the container next index to get the index of the next element, previous index it returns.
+
+215
+00:15:29,000 --> 00:15:36,000
+The element that would be returned by previous MassArt set replaces the last element that was returned.
+
+216
+00:15:36,000 --> 00:15:38,000
+And this is important to understand.
+
+217
+00:15:39,000 --> 00:15:46,000
+It replaces elements that was returned after the next or previous method in case that method is called
+
+218
+00:15:46,000 --> 00:15:51,000
+without calling next the previous method before that illegal state exception strong.
+
+219
+00:15:51,000 --> 00:15:59,000
+Add method adds element to the container so you can see a few more important features of the list iterator.
+
+220
+00:15:59,000 --> 00:16:05,000
+It also allows us to add element to the container during the iteration over elements or to substitute
+
+221
+00:16:05,000 --> 00:16:05,000
+elements.
+
+222
+00:16:06,000 --> 00:16:08,000
+Let's look at the list, iterator them.
+
+223
+00:16:08,000 --> 00:16:11,000
+Now, I created a separate file for that.
+
+224
+00:16:11,000 --> 00:16:13,000
+Let me also execute this program.
+
+225
+00:16:14,000 --> 00:16:17,000
+I have the same container was integers as in previous example.
+
+226
+00:16:17,000 --> 00:16:19,000
+The list interface declares list.
+
+227
+00:16:19,000 --> 00:16:20,000
+Iterate the method.
+
+228
+00:16:20,000 --> 00:16:25,000
+As you remember, this method returns as the objects of list iterator type.
+
+229
+00:16:26,000 --> 00:16:27,000
+One more interesting feature.
+
+230
+00:16:27,000 --> 00:16:31,000
+We can get at least iterator from the specific position if we need.
+
+231
+00:16:31,000 --> 00:16:36,000
+I can't imagine the case when I would use it, but it is interesting feature to know about.
+
+232
+00:16:36,000 --> 00:16:39,000
+List Iterator, for example.
+
+233
+00:16:39,000 --> 00:16:41,000
+Here I set List Iterator as a second index.
+
+234
+00:16:42,000 --> 00:16:48,000
+Here is a position of the cursor in the index zero here, position of the cursor in the index one and
+
+235
+00:16:48,000 --> 00:16:49,000
+here is two.
+
+236
+00:16:50,000 --> 00:16:54,000
+So the next goal of the previous method should return number two.
+
+237
+00:16:55,000 --> 00:16:59,000
+And now you can see in the console output that two is returned.
+
+238
+00:16:59,000 --> 00:17:02,000
+Now I want to update this element.
+
+239
+00:17:02,000 --> 00:17:06,000
+I call set method and pass twenty two this method.
+
+240
+00:17:06,000 --> 00:17:10,000
+So the elements that was returned previously is substituted with twenty.
+
+241
+00:17:11,000 --> 00:17:17,000
+So my next goal of the next method should return twenty and he and console you can see at least Iterator
+
+242
+00:17:17,000 --> 00:17:20,000
+works exactly in the way we expect it to work.
+
+243
+00:17:21,000 --> 00:17:27,000
+In case I want to add an element with the help of this iterator, I call add method and the item is
+
+244
+00:17:27,000 --> 00:17:29,000
+inserted right before the cursor.
+
+245
+00:17:30,000 --> 00:17:36,000
+So in case I added twenty one, I can get it now by calling the previous method and here's twenty one
+
+246
+00:17:37,000 --> 00:17:42,000
+and remove mass at the last item that was returned either by next or previous method.
+
+247
+00:17:43,000 --> 00:17:50,000
+In this case after location of remove method twenty one will be removed and here we printed all elements
+
+248
+00:17:50,000 --> 00:17:51,000
+to console to prove this.
+
+249
+00:17:52,000 --> 00:17:57,000
+Now, I believe you have a full understanding of how Étretat enlisted radar works.
+
+250
+00:17:57,000 --> 00:17:59,000
+Let's recap what we have learned today.
+
+251
+00:18:00,000 --> 00:18:02,000
+Today, we learned what iterable is.
+
+252
+00:18:02,000 --> 00:18:06,000
+We also understand what Iterator is now.
+
+253
+00:18:06,000 --> 00:18:12,000
+We know the difference between these two interfaces when real examples, we saw how Iterator works in
+
+254
+00:18:12,000 --> 00:18:13,000
+this lesson.
+
+255
+00:18:13,000 --> 00:18:18,000
+We saw what exceptions might be thrown by iterator, including concurrent modification, exception,
+
+256
+00:18:18,000 --> 00:18:23,000
+illegal state exception, unsupported aliment exception and no such aliment exception.
+
+257
+00:18:24,000 --> 00:18:29,000
+We learned three types of iterator fail fast, fail safe and weakly consistent.
+
+258
+00:18:30,000 --> 00:18:34,000
+And at the end of the lesson we learned at least iterator and how it works.
+
+259
+00:18:34,000 --> 00:18:36,000
+Now let's review your homework.
+
+260
+00:18:37,000 --> 00:18:43,000
+In short, you have to coordinate exercises here, you have to implement Iterator and Lisa the for the
+
+261
+00:18:43,000 --> 00:18:50,000
+default Miley's class that you implemented in scoping her homework about lists, read attentively all
+
+262
+00:18:50,000 --> 00:18:54,000
+the requirements here I prepared for you method signatures and description of interfaces.
+
+263
+00:18:55,000 --> 00:18:57,000
+All you have to do is implement methods.
+
+264
+00:18:58,000 --> 00:19:03,000
+You will see here some requirements related to exceptions in case you are not familiar with exceptions
+
+265
+00:19:03,000 --> 00:19:04,000
+topic.
+
+266
+00:19:04,000 --> 00:19:09,000
+There is absolutely no harm because I wrote the line of code that you have to write.
+
+267
+00:19:09,000 --> 00:19:15,000
+One exceptions should be thrown that said, don't skip this homework.
+
+268
+00:19:15,000 --> 00:19:17,000
+It is important for understanding of the topic.
+
+269
+00:19:18,000 --> 00:19:19,000
+Thanks a lot for your attention.
+
+270
+00:19:19,000 --> 00:19:21,000
+See you in the next lesson.
+

19 - Java Collections Framework/010 Source-code-of-the-examples-used-in-the-lesson.url

@@ -0,0 +1,2 @@
+[InternetShortcut]
+URL=https://github.com/AndriiPiatakha/learnit_java_core/tree/master/src/com/itbulls/learnit/javacore/jcf/collections/iterator

19 - Java Collections Framework/012 Homework.url

@@ -0,0 +1,2 @@
+[InternetShortcut]
+URL=https://docs.google.com/document/d/1EJinEXmADmEbqDnRdz9y6OITVDwhCN7K7FLMjbtE4zs/edit?usp=sharing

19 - Java Collections Framework/012 Queue and Deque_en.srt

@@ -0,0 +1,1072 @@
+1
+00:00:06,000 --> 00:00:06,000
+Hello, Jim.
+
+2
+00:00:06,000 --> 00:00:10,000
+Today, we are going to lunch with you and other collections of Iraq.
+
+3
+00:00:10,000 --> 00:00:15,000
+Today we'll talk about you interface and one more important interface that extends you, that is that
+
+4
+00:00:15,000 --> 00:00:19,000
+interface with the masses in interface.
+
+5
+00:00:19,000 --> 00:00:24,000
+And I hope you didn't skip lessons because in previous lessons during the General Overy, we already
+
+6
+00:00:24,000 --> 00:00:28,000
+talked about you and discussed Masset that this interface has.
+
+7
+00:00:29,000 --> 00:00:31,000
+But today we'll dive into the details.
+
+8
+00:00:31,000 --> 00:00:34,000
+After that, we'll learn methods in that interface.
+
+9
+00:00:34,000 --> 00:00:38,000
+Today, we're going to learn what is the difference between these two interfaces.
+
+10
+00:00:39,000 --> 00:00:44,000
+Also, we'll learn what FTF old principle is and what LIFO principle is.
+
+11
+00:00:45,000 --> 00:00:51,000
+After we learn interfaces, we'll take a look at the most popular Q and deck implementations.
+
+12
+00:00:51,000 --> 00:00:54,000
+And I will share with you practical tips and practical cases.
+
+13
+00:00:55,000 --> 00:01:00,000
+And at the end of the lesson, we are going to review your home task and I will explain how you can
+
+14
+00:01:00,000 --> 00:01:01,000
+practice your skills.
+
+15
+00:01:01,000 --> 00:01:07,000
+Let's start and to understand what CU is, we have to understand what FTF old principle is.
+
+16
+00:01:08,000 --> 00:01:16,000
+If you don't skip lessons, then you remember that FCF also is a method of organizing of a data structure
+
+17
+00:01:16,000 --> 00:01:22,000
+where the first elements that enter the queue, the first leifs is a Q, in other words, the head of
+
+18
+00:01:22,000 --> 00:01:30,000
+the queue always processed first f i f o stands for first in first out here on the slide you may see
+
+19
+00:01:30,000 --> 00:01:34,000
+brutalisation of the Q the Q has the head and the tail.
+
+20
+00:01:35,000 --> 00:01:41,000
+Students usually wondered where the heart of the Q is and where style of the Q by convention.
+
+21
+00:01:41,000 --> 00:01:49,000
+The end of the queue at which elements are added is called the tail back Oriya of the Q The end at which
+
+22
+00:01:49,000 --> 00:01:53,000
+elements are removed is called the hat or front of the Q.
+
+23
+00:01:53,000 --> 00:01:58,000
+Analogously two words used when people line up to wait for goods or services.
+
+24
+00:01:58,000 --> 00:02:00,000
+Does it make sense now?
+
+25
+00:02:00,000 --> 00:02:03,000
+If yes, then let's answer our next question.
+
+26
+00:02:03,000 --> 00:02:05,000
+Where Q is used.
+
+27
+00:02:05,000 --> 00:02:07,000
+Imagine that you have two services.
+
+28
+00:02:07,000 --> 00:02:11,000
+The first service is in charge of onboarding of new customer.
+
+29
+00:02:11,000 --> 00:02:18,000
+This service process information about the user verifies his payment method at him to the theorem,
+
+30
+00:02:18,000 --> 00:02:24,000
+checks whether this user already registered, etc. Let's call it onboarding service.
+
+31
+00:02:24,000 --> 00:02:30,000
+And another service is in charge of handling all payments from the user for his subscription on a monthly
+
+32
+00:02:30,000 --> 00:02:30,000
+basis.
+
+33
+00:02:31,000 --> 00:02:33,000
+Let's call this payment service.
+
+34
+00:02:33,000 --> 00:02:39,000
+Those are two independent services because the first one is in charge of selling subscriptions to customer
+
+35
+00:02:39,000 --> 00:02:41,000
+only on one side.
+
+36
+00:02:41,000 --> 00:02:47,000
+But they are different of the similar marketing sites that promotes different products and services
+
+37
+00:02:47,000 --> 00:02:47,000
+of the company.
+
+38
+00:02:48,000 --> 00:02:54,000
+Our onboarding service is one out of many services, but the service that is responsible for charging
+
+39
+00:02:54,000 --> 00:03:00,000
+clients on a monthly basis is used by all websites and systems within the same company.
+
+40
+00:03:01,000 --> 00:03:06,000
+This is real life scenarios that my team implemented in simplified form also.
+
+41
+00:03:06,000 --> 00:03:08,000
+But still, I believe you got my point.
+
+42
+00:03:08,000 --> 00:03:14,000
+And before process payment information from any of the website, the queue exists.
+
+43
+00:03:14,000 --> 00:03:21,000
+It exists right in the middle between all services and charge and service and all services, including
+
+44
+00:03:21,000 --> 00:03:25,000
+our onboarding service submits the message in the queue.
+
+45
+00:03:25,000 --> 00:03:33,000
+The message contains payment profile of our customer and product details and our payment service process.
+
+46
+00:03:33,000 --> 00:03:39,000
+All these messages one by one and implements all necessary logic related for recurring payments.
+
+47
+00:03:40,000 --> 00:03:41,000
+Does it make more sense now?
+
+48
+00:03:42,000 --> 00:03:43,000
+Can you understand now?
+
+49
+00:03:43,000 --> 00:03:45,000
+Why do we need Kyuss hope?
+
+50
+00:03:45,000 --> 00:03:49,000
+This brings more clarity and you understand why we need to use Qs.
+
+51
+00:03:50,000 --> 00:03:57,000
+OK, if you understood cuz let's understand what a deck is and to understand that we have to understand
+
+52
+00:03:57,000 --> 00:03:59,000
+what LIFO principle is.
+
+53
+00:04:00,000 --> 00:04:06,000
+LIFO is a method of organizing the manipulation of a data, whereas the last element that entered the
+
+54
+00:04:06,000 --> 00:04:09,000
+container should be processed first.
+
+55
+00:04:09,000 --> 00:04:12,000
+LIFO stands for Last In, First Out.
+
+56
+00:04:13,000 --> 00:04:19,000
+If you remember stack class that extends vector, that is also implementation of LIFO principle.
+
+57
+00:04:20,000 --> 00:04:23,000
+And on the screen you can see visualisation of stack.
+
+58
+00:04:23,000 --> 00:04:30,000
+But where we might want to apply LIFO principle, the easiest example of that usage, which you are
+
+59
+00:04:30,000 --> 00:04:32,000
+faced with on a daily basis, is in the clips.
+
+60
+00:04:33,000 --> 00:04:36,000
+Have you ever used and do operations in Eclipse?
+
+61
+00:04:36,000 --> 00:04:38,000
+How do you think the operation works?
+
+62
+00:04:39,000 --> 00:04:45,000
+Each batch of changes is put in the stack and then the case and those short cards is correct.
+
+63
+00:04:45,000 --> 00:04:48,000
+The latest separation is removed from the stack.
+
+64
+00:04:48,000 --> 00:04:51,000
+For example, you wrote Hello World.
+
+65
+00:04:51,000 --> 00:04:54,000
+The World World is on top of your stack.
+
+66
+00:04:54,000 --> 00:04:58,000
+When you want to run the operation, it leaves the stack first.
+
+67
+00:04:58,000 --> 00:05:00,000
+Or imagine your browser history.
+
+68
+00:05:00,000 --> 00:05:02,000
+You open new pages and then you need.
+
+69
+00:05:03,000 --> 00:05:10,000
+The return on the previous page or asset allocation in your Java program, we can call one message from
+
+70
+00:05:10,000 --> 00:05:16,000
+another one and after that call one more method how to track the flow of program execution only with
+
+71
+00:05:16,000 --> 00:05:23,000
+the help of the stack data structure that stores elements according to LIFO method that it makes more
+
+72
+00:05:23,000 --> 00:05:23,000
+sense.
+
+73
+00:05:23,000 --> 00:05:26,000
+Now, can you understand now when do we need stack?
+
+74
+00:05:27,000 --> 00:05:27,000
+Awesome.
+
+75
+00:05:28,000 --> 00:05:34,000
+And now when you understood what CU and DEC is and why we need them, I suggest dive deeper into the
+
+76
+00:05:34,000 --> 00:05:36,000
+details and learn interfaces.
+
+77
+00:05:36,000 --> 00:05:40,000
+Here is a new interface we have at and of a message here.
+
+78
+00:05:41,000 --> 00:05:43,000
+Both exist to add elements to the queue.
+
+79
+00:05:44,000 --> 00:05:47,000
+Both returns through in case element was added to the queue.
+
+80
+00:05:48,000 --> 00:05:52,000
+Then why do we need two similar methods and why do we need add method here?
+
+81
+00:05:52,000 --> 00:05:54,000
+If it is present in collection interface?
+
+82
+00:05:55,000 --> 00:06:01,000
+Let's understand the difference at that is present in queue interface to highlight the specific behavior
+
+83
+00:06:01,000 --> 00:06:06,000
+of that method in queue type add method adds elements to the queue.
+
+84
+00:06:06,000 --> 00:06:12,000
+But as you can see from the documentation here in legal state, exceptions will be thrown in case element
+
+85
+00:06:12,000 --> 00:06:15,000
+couldn't be added because of the capacity restrictions.
+
+86
+00:06:16,000 --> 00:06:21,000
+To be honest, in most of the cases you wouldn't see this error while working with the implementation
+
+87
+00:06:21,000 --> 00:06:23,000
+of the queue interface.
+
+88
+00:06:23,000 --> 00:06:23,000
+Why?
+
+89
+00:06:24,000 --> 00:06:29,000
+Because most of the implementations have no restrictions on capacity and their unbounded.
+
+90
+00:06:30,000 --> 00:06:34,000
+And in this case there is no difference between at and of.
+
+91
+00:06:34,000 --> 00:06:41,000
+A method of a method doesn't throw exception in case element is not added because of the capacity restrictions.
+
+92
+00:06:41,000 --> 00:06:44,000
+It also can return false hope.
+
+93
+00:06:44,000 --> 00:06:49,000
+This knowledge will help you during the interview, in case you will be asked what the difference is
+
+94
+00:06:49,000 --> 00:06:52,000
+between add and offer method in queue interface.
+
+95
+00:06:52,000 --> 00:06:53,000
+Let's move on.
+
+96
+00:06:53,000 --> 00:06:58,000
+We have two methods to retrieve elements from the heart of the queue and remove it from the queue.
+
+97
+00:06:59,000 --> 00:07:01,000
+Zaya, remove and pull.
+
+98
+00:07:01,000 --> 00:07:06,000
+The only difference between them is the way how they behave in case there are no more elements in the
+
+99
+00:07:06,000 --> 00:07:07,000
+queue.
+
+100
+00:07:07,000 --> 00:07:13,000
+Remove Masset in this case will throw no such element exception and Paul MassArt will just returns.
+
+101
+00:07:13,000 --> 00:07:16,000
+And now what do you see in real life?
+
+102
+00:07:16,000 --> 00:07:19,000
+I would say evaluate the logic of execution of your program.
+
+103
+00:07:19,000 --> 00:07:26,000
+First, in case you would ask me what method I would use, I would use full method and would just perform
+
+104
+00:07:26,000 --> 00:07:26,000
+null check.
+
+105
+00:07:27,000 --> 00:07:31,000
+I just afraid of all exceptions and I would rather opt for options.
+
+106
+00:07:31,000 --> 00:07:37,000
+That doesn't throw an exception, but all cases and programming styles are different and I can accept
+
+107
+00:07:37,000 --> 00:07:38,000
+that.
+
+108
+00:07:38,000 --> 00:07:40,000
+And that's why it's up to you.
+
+109
+00:07:40,000 --> 00:07:44,000
+Which method to choose is a similar situation with the next two methods.
+
+110
+00:07:45,000 --> 00:07:50,000
+We have two methods that allows us to get the elements from the head of the queue, but that don't remove
+
+111
+00:07:50,000 --> 00:07:54,000
+element from the queue zaya element and pick.
+
+112
+00:07:55,000 --> 00:07:58,000
+The only difference is that element Masad Maestro.
+
+113
+00:07:58,000 --> 00:08:03,000
+No such element exception in case there is no more aliments and big method would just return.
+
+114
+00:08:03,000 --> 00:08:06,000
+Now you already know what I would choose.
+
+115
+00:08:06,000 --> 00:08:09,000
+That's all methods that are declared in queue interface.
+
+116
+00:08:09,000 --> 00:08:14,000
+Let's move further and let's investigate what message do we have in that interface.
+
+117
+00:08:14,000 --> 00:08:22,000
+So as we already discussed, that extends queue interface and organizes data according to LIFG principle.
+
+118
+00:08:23,000 --> 00:08:28,000
+Let's review methods now that are present here in the top of our list.
+
+119
+00:08:28,000 --> 00:08:34,000
+We can find a lot of similar methods that can work with the head and with the tail of the queue at first
+
+120
+00:08:34,000 --> 00:08:37,000
+and at last of a first and of last.
+
+121
+00:08:38,000 --> 00:08:44,000
+Remove first and remove last, both first and last week first and pick last.
+
+122
+00:08:44,000 --> 00:08:46,000
+I believe it is clear how they work.
+
+123
+00:08:46,000 --> 00:08:52,000
+Since we discussed similar methods in queue interface, I noticed that there is no element first and
+
+124
+00:08:52,000 --> 00:08:57,000
+element last method if to follow the analogy in is naming.
+
+125
+00:08:57,000 --> 00:09:03,000
+But do we have methods that doesn't remove element from the queue and throws an exception in case there
+
+126
+00:09:03,000 --> 00:09:03,000
+is no element?
+
+127
+00:09:04,000 --> 00:09:08,000
+Yes, we have aget first and last method here.
+
+128
+00:09:08,000 --> 00:09:14,000
+They here also to interest in masses, remove first Securus and remove last appearance.
+
+129
+00:09:14,000 --> 00:09:20,000
+When we are referring to the first occurrence, we mean first in case we would reverse elements from
+
+130
+00:09:20,000 --> 00:09:21,000
+the had the tail.
+
+131
+00:09:21,000 --> 00:09:27,000
+So the first Securus will be closer to the heart of the queue and the last appearance is closer to the
+
+132
+00:09:27,000 --> 00:09:28,000
+tail of the queue.
+
+133
+00:09:29,000 --> 00:09:36,000
+After that abasic message from the queue go here and en masse, it adds all elements to the container,
+
+134
+00:09:36,000 --> 00:09:39,000
+the same as it is declared in connection interface.
+
+135
+00:09:39,000 --> 00:09:45,000
+There is only one clarification that all elements will be inserted into the end of the queue.
+
+136
+00:09:45,000 --> 00:09:47,000
+And here are static methods.
+
+137
+00:09:47,000 --> 00:09:53,000
+We already discussed what the stack is and here's a mass to manage stack push.
+
+138
+00:09:53,000 --> 00:09:55,000
+It adds element in the heart of the queue.
+
+139
+00:09:55,000 --> 00:09:58,000
+This method will throw illegal state exception in the case.
+
+140
+00:09:58,000 --> 00:10:02,000
+Element can't be added due to capacity restrictions.
+
+141
+00:10:02,000 --> 00:10:05,000
+This method is similar to at first method.
+
+142
+00:10:05,000 --> 00:10:08,000
+This is even specified in general documentation.
+
+143
+00:10:08,000 --> 00:10:10,000
+Then why do we need it at all?
+
+144
+00:10:11,000 --> 00:10:16,000
+For compatibility reasons with legacy class stack, the push and pop methods exist.
+
+145
+00:10:16,000 --> 00:10:21,000
+This means that they're only to make a transition of all code easier for programa.
+
+146
+00:10:22,000 --> 00:10:26,000
+The pop method is here and it is equivalent of remove first MassArt.
+
+147
+00:10:27,000 --> 00:10:32,000
+And I believe you already understood why Oracle left this method in this interface.
+
+148
+00:10:32,000 --> 00:10:36,000
+The last message that we didn't talk about is the sending iterator.
+
+149
+00:10:37,000 --> 00:10:42,000
+This message, according to the interface, should return iterator objects that can iterate over the
+
+150
+00:10:42,000 --> 00:10:44,000
+elements in reverse sequential order.
+
+151
+00:10:45,000 --> 00:10:50,000
+That is from the last element from our tail to the first element to our hat.
+
+152
+00:10:51,000 --> 00:10:54,000
+That's all matters that we have in our back interface.
+
+153
+00:10:54,000 --> 00:10:58,000
+Now let's investigate the most popular Q and deck implementations.
+
+154
+00:10:59,000 --> 00:11:05,000
+On this slide, you can see the most popular implementations of Q and back interfaces, I recommend
+
+155
+00:11:05,000 --> 00:11:08,000
+you post the video and read the slide attentively.
+
+156
+00:11:09,000 --> 00:11:13,000
+I believe there is no need to investigate each of these class in details.
+
+157
+00:11:13,000 --> 00:11:19,000
+It is better to put our focus on the most popular implementations, the most popular implementation,
+
+158
+00:11:19,000 --> 00:11:26,000
+in my opinion, and based on the official Oracle tutorials can be split in two major categories implementations
+
+159
+00:11:26,000 --> 00:11:30,000
+of the interface and implementations of just rescue interface.
+
+160
+00:11:30,000 --> 00:11:36,000
+In case you need the implementations, then most likely you will be happy with slinked list or array
+
+161
+00:11:36,000 --> 00:11:37,000
+that class.
+
+162
+00:11:37,000 --> 00:11:43,000
+If you need Q implementations, most likely you will opt for lenth list of priority queue if you need
+
+163
+00:11:43,000 --> 00:11:45,000
+thread safe implementations of the queue.
+
+164
+00:11:45,000 --> 00:11:50,000
+I would like to draw attention to avoid blocking Q and priority blocking queue.
+
+165
+00:11:50,000 --> 00:11:55,000
+If you need thread safe implementations of DEC, then your choice is linked lock and DEC.
+
+166
+00:11:56,000 --> 00:11:58,000
+As you can see there is really a lot of options.
+
+167
+00:11:59,000 --> 00:12:06,000
+But in my opinion and based on my experience in 95 percent of cases when you would need to use DEC implementation
+
+168
+00:12:06,000 --> 00:12:12,000
+to implement some stack or in case you would need Q you would use in case class the rest five percent
+
+169
+00:12:12,000 --> 00:12:17,000
+of cases is for thread safe implementation of the Q and DEC and also priority.
+
+170
+00:12:17,000 --> 00:12:25,000
+Q taking into account we already had lesson about Lindley's and we already learned the Q and DEC interfaces.
+
+171
+00:12:25,000 --> 00:12:29,000
+There will be nothing hard for you just to call these methods on linked list.
+
+172
+00:12:29,000 --> 00:12:34,000
+And that is why, for the sake of the demo, I would like to show you how AQ works on the example of
+
+173
+00:12:34,000 --> 00:12:35,000
+priority.
+
+174
+00:12:35,000 --> 00:12:38,000
+Q So here I prepared them file.
+
+175
+00:12:38,000 --> 00:12:43,000
+I will leave link to this file in attachments to the lesson so that you could copy and run this file
+
+176
+00:12:43,000 --> 00:12:44,000
+on your local computer.
+
+177
+00:12:45,000 --> 00:12:47,000
+Here I declare it variable of type.
+
+178
+00:12:47,000 --> 00:12:51,000
+Q Parametrized with the integer type here I created object of.
+
+179
+00:12:52,000 --> 00:12:57,000
+Q And in these lines you can see that I added to the Q five elements.
+
+180
+00:12:57,000 --> 00:13:00,000
+They are two eight three one then.
+
+181
+00:13:01,000 --> 00:13:05,000
+So in the case I'd like to take the first element in the Q what it would be.
+
+182
+00:13:06,000 --> 00:13:10,000
+Take your time to think about this question because this is a trick question.
+
+183
+00:13:11,000 --> 00:13:17,000
+We all know how Q works and what is a five for principle, but priority Q has interesting feature.
+
+184
+00:13:18,000 --> 00:13:22,000
+It automatically source elements according to the natural order.
+
+185
+00:13:22,000 --> 00:13:26,000
+I hope you didn't skip the lesson about comparator uncomparable.
+
+186
+00:13:26,000 --> 00:13:32,000
+And you know that natural order is an order that is described in the compared to method because of implementation
+
+187
+00:13:32,000 --> 00:13:33,000
+of comparable interface.
+
+188
+00:13:34,000 --> 00:13:40,000
+And that's where a provocative word comes from in the name of the Q it prioritize elements.
+
+189
+00:13:40,000 --> 00:13:46,000
+So in case I would prefer to control the elements from the head of the Q this would be one even despite
+
+190
+00:13:46,000 --> 00:13:50,000
+integer object was well your one wasn't inserted the first.
+
+191
+00:13:51,000 --> 00:13:53,000
+Let me run the program to show you this.
+
+192
+00:13:53,000 --> 00:13:57,000
+I used polymathic to get elements from the Q and remove it.
+
+193
+00:13:57,000 --> 00:14:04,000
+So the size of the Q right now is four now in case I call Big Masset and get the hell out of the Q,
+
+194
+00:14:04,000 --> 00:14:07,000
+but don't remove element here.
+
+195
+00:14:07,000 --> 00:14:11,000
+You can see in console output that our next object and our priority.
+
+196
+00:14:11,000 --> 00:14:13,000
+Q is to and the size of the peak.
+
+197
+00:14:14,000 --> 00:14:21,000
+It is still four because I didn't remove elements from the Q Pay attention to the fact that all elements
+
+198
+00:14:21,000 --> 00:14:22,000
+that you put into the priority.
+
+199
+00:14:22,000 --> 00:14:28,000
+Q should implement comparable interface because in case type doesn't implement comparable interface,
+
+200
+00:14:28,000 --> 00:14:35,000
+Breuer's UCU object would throw exception, glossiest exception that would say that your type cannot
+
+201
+00:14:35,000 --> 00:14:37,000
+be cast to comparable type.
+
+202
+00:14:37,000 --> 00:14:39,000
+Let me show you an example.
+
+203
+00:14:39,000 --> 00:14:46,000
+Let me comment these lines of code here, you can see that I create Q Parametrized by product type.
+
+204
+00:14:46,000 --> 00:14:53,000
+Just to remind you, product is our custom type that we created during our work on online store implementation.
+
+205
+00:14:53,000 --> 00:14:56,000
+After that, I want to place my product into this.
+
+206
+00:14:56,000 --> 00:15:04,000
+Q Let me run the program to show you what would happen and here you can see glass cast exception.
+
+207
+00:15:04,000 --> 00:15:05,000
+What to do now?
+
+208
+00:15:06,000 --> 00:15:07,000
+We have two options here.
+
+209
+00:15:08,000 --> 00:15:13,000
+The first one is to use only types that implement comparable interface.
+
+210
+00:15:13,000 --> 00:15:16,000
+The second option is to set our priority.
+
+211
+00:15:16,000 --> 00:15:18,000
+Q How to compare elements.
+
+212
+00:15:18,000 --> 00:15:23,000
+Let me comment these lines of code to show you the next example here.
+
+213
+00:15:23,000 --> 00:15:29,000
+You can see that I created the same Q Parametrized by product type, but I pass the product comparison
+
+214
+00:15:29,000 --> 00:15:31,000
+to the constructor of prosecute.
+
+215
+00:15:32,000 --> 00:15:40,000
+Now my project knows how to compare products and saw them let me run the program and we can't see error
+
+216
+00:15:40,000 --> 00:15:40,000
+anymore.
+
+217
+00:15:41,000 --> 00:15:47,000
+That is because our Q knows how to prioritize products, where to use priority.
+
+218
+00:15:47,000 --> 00:15:51,000
+Q Imagine that you want to implement helpdesk during the day.
+
+219
+00:15:51,000 --> 00:15:57,000
+You receive tons of requests and complaints, but you have limited number of operators in your company
+
+220
+00:15:57,000 --> 00:15:58,000
+that can.
+
+221
+00:15:58,000 --> 00:16:05,000
+These requests and you have special app for your operators where each operator can click a button,
+
+222
+00:16:05,000 --> 00:16:12,000
+they can request and move it in progress, and it is obvious that most critical requests should be processed
+
+223
+00:16:12,000 --> 00:16:18,000
+first in case a customer can't make a payment in the online store or customer already paid.
+
+224
+00:16:18,000 --> 00:16:23,000
+But some error happened and he or she can't get details of his order.
+
+225
+00:16:23,000 --> 00:16:29,000
+That is more critical than some random question, like one sorting by manufacturer will be implemented
+
+226
+00:16:29,000 --> 00:16:30,000
+on your site.
+
+227
+00:16:30,000 --> 00:16:37,000
+They agree with me and what you have to do probably on the front end, you would implement some dropdown
+
+228
+00:16:37,000 --> 00:16:40,000
+where you would ask your customer to categorize request.
+
+229
+00:16:41,000 --> 00:16:47,000
+For example, here on the slide you can see example of support of Panya in your system.
+
+230
+00:16:47,000 --> 00:16:50,000
+You have some object, something like support ticket type.
+
+231
+00:16:50,000 --> 00:16:54,000
+You also have to implement logic that would assign support ticket type.
+
+232
+00:16:54,000 --> 00:17:00,000
+And based on the type of the request, you would assign priority, high, medium or low.
+
+233
+00:17:00,000 --> 00:17:04,000
+And after that you would pull your support ticket object into the queue.
+
+234
+00:17:05,000 --> 00:17:11,000
+And you already know that we have to either implement compatible interface in our support ticket or
+
+235
+00:17:11,000 --> 00:17:14,000
+we have to create a competitor and pass it to priority queue.
+
+236
+00:17:14,000 --> 00:17:15,000
+Interesting.
+
+237
+00:17:15,000 --> 00:17:17,000
+I hope it is.
+
+238
+00:17:17,000 --> 00:17:23,000
+And moreover, implementing something like this already a real life task for our software engineer.
+
+239
+00:17:23,000 --> 00:17:25,000
+This will be your homework.
+
+240
+00:17:25,000 --> 00:17:30,000
+But before I would share with you the details of your homework, let's recap what we have learned today.
+
+241
+00:17:31,000 --> 00:17:33,000
+Today we learned Q and DEC interfaces.
+
+242
+00:17:34,000 --> 00:17:38,000
+We learned in detail how matters that are described in these interfaces work.
+
+243
+00:17:39,000 --> 00:17:43,000
+We learned what a FFO and LIFO data store methods are.
+
+244
+00:17:44,000 --> 00:17:49,000
+We used you and DEC implementations and learned the most popular ones after that.
+
+245
+00:17:49,000 --> 00:17:56,000
+On the real example, we learned how particular works and now I suggest reviewing your homework.
+
+246
+00:17:56,000 --> 00:18:02,000
+You have to implement helpdesk facades that would serve as a main interface for a support engineer to
+
+247
+00:18:02,000 --> 00:18:09,000
+interact with the system, helpdesk facade interface has only three masses that you support.
+
+248
+00:18:09,000 --> 00:18:16,000
+You could get next support ticket and get a number of tickets according to our requirements, get next
+
+249
+00:18:16,000 --> 00:18:16,000
+support ticket.
+
+250
+00:18:16,000 --> 00:18:20,000
+Masset will be called when your support engineer would click on the button.
+
+251
+00:18:21,000 --> 00:18:24,000
+This message should return top priority item.
+
+252
+00:18:24,000 --> 00:18:29,000
+I almost explained to you how to implement Help Desk in the online store.
+
+253
+00:18:29,000 --> 00:18:35,000
+Here you can find the details about what request type might be and priority for specific request type
+
+254
+00:18:36,000 --> 00:18:42,000
+during the creation of the support ticket will specify only typos request and its priority is defined
+
+255
+00:18:42,000 --> 00:18:45,000
+automatically based on the Moppin that are written down in the table.
+
+256
+00:18:46,000 --> 00:18:48,000
+And there is one more requirement in the case.
+
+257
+00:18:48,000 --> 00:18:51,000
+Support tickets have the same priority.
+
+258
+00:18:51,000 --> 00:18:54,000
+The one that was created earlier should be processed first.
+
+259
+00:18:55,000 --> 00:18:57,000
+I can give you a small hint here.
+
+260
+00:18:57,000 --> 00:18:58,000
+You can implement counter.
+
+261
+00:18:59,000 --> 00:19:04,000
+This even might be static field and you may consider the value of this field when you would compare
+
+262
+00:19:04,000 --> 00:19:06,000
+to support tickets, for example.
+
+263
+00:19:06,000 --> 00:19:08,000
+Does it make sense home?
+
+264
+00:19:08,000 --> 00:19:09,000
+The task is clear for you.
+
+265
+00:19:10,000 --> 00:19:15,000
+This is a really interesting task that will help you a lot in understanding of the cues and will give
+
+266
+00:19:15,000 --> 00:19:17,000
+you some clues to real life experience.
+
+267
+00:19:18,000 --> 00:19:19,000
+Thank you all for your attention.
+
+268
+00:19:19,000 --> 00:19:22,000
+Have a great day and see you in the next lesson.
+

19 - Java Collections Framework/012 Solution-for-Homework-Back-end-system-for-help-desk.url

@@ -0,0 +1,2 @@
+[InternetShortcut]
+URL=https://github.com/AndriiPiatakha/learnit_java_core/tree/master/src/com/itbulls/learnit/javacore/jcf/hw/onlinestore/withlist/helpdesk

19 - Java Collections Framework/012 Source-code-of-the-example-used-in-the-lesson.url

@@ -0,0 +1,2 @@
+[InternetShortcut]
+URL=https://github.com/AndriiPiatakha/learnit_java_core/blob/master/src/com/itbulls/learnit/javacore/jcf/collections/queue/QueueDemo.java

19 - Java Collections Framework/014 Map Hierarchy_en.srt

@@ -0,0 +1,876 @@
+1
+00:00:06,000 --> 00:00:11,000
+Hello, dear students, today we have important topic we are going to review another Iraq of Java collections
+
+2
+00:00:11,000 --> 00:00:14,000
+framework that is MOP Iraqi today.
+
+3
+00:00:14,000 --> 00:00:16,000
+We are going to run map interface.
+
+4
+00:00:16,000 --> 00:00:20,000
+We are also going to review such interfaces like sorted map and navigable map.
+
+5
+00:00:21,000 --> 00:00:26,000
+I'm going to hold overview of implementations of map interface and what features they have.
+
+6
+00:00:27,000 --> 00:00:32,000
+Also, we'll talk about what the dictionary is and how hash tablecloth is different from hash map.
+
+7
+00:00:32,000 --> 00:00:37,000
+After we learn, Ceri will focus on map interface and its methods.
+
+8
+00:00:37,000 --> 00:00:39,000
+Your review of map interface.
+
+9
+00:00:39,000 --> 00:00:41,000
+We also will learn what entry type is.
+
+10
+00:00:42,000 --> 00:00:46,000
+As you can see that we have a lot of things to learn in our plans.
+
+11
+00:00:46,000 --> 00:00:53,000
+Let's start and I'd like to start with you from the overview of Map Iraqi first and the key features
+
+12
+00:00:53,000 --> 00:00:53,000
+of MAP.
+
+13
+00:00:54,000 --> 00:01:00,000
+And after we learn this, we are going to dive deeper in the details to investigate each interface in
+
+14
+00:01:00,000 --> 00:01:04,000
+particular on the top of our Iraqi, we have map interface.
+
+15
+00:01:04,000 --> 00:01:07,000
+This type exists to map keys to values.
+
+16
+00:01:07,000 --> 00:01:11,000
+All keys are unique, various may be duplicated.
+
+17
+00:01:11,000 --> 00:01:15,000
+And there are a lot of places and our programs where we can apply map implementations.
+
+18
+00:01:16,000 --> 00:01:22,000
+If you remember on one of the lessons I showed you example of mobile app for sports betting tips, for
+
+19
+00:01:22,000 --> 00:01:26,000
+example, we can receive from server a lot of sports events.
+
+20
+00:01:26,000 --> 00:01:33,000
+After that, we can group them by date and your keyword would be the specific date and the value would
+
+21
+00:01:33,000 --> 00:01:38,000
+be a collection of sporting events on this day or another example, recently you have implemented Home
+
+22
+00:01:38,000 --> 00:01:40,000
+Task Help Desk.
+
+23
+00:01:40,000 --> 00:01:41,000
+In that task.
+
+24
+00:01:41,000 --> 00:01:44,000
+You also could use map implementations to map support.
+
+25
+00:01:44,000 --> 00:01:47,000
+Request type was its priority.
+
+26
+00:01:47,000 --> 00:01:53,000
+In this case, support request type would be the key and it will be unique and priority would be the
+
+27
+00:01:53,000 --> 00:01:55,000
+value and can be duplicated.
+
+28
+00:01:56,000 --> 00:02:01,000
+And I keep creating examples on the fly because there really are a lot of cases where you need some
+
+29
+00:02:01,000 --> 00:02:04,000
+data structure where you would store key value pass.
+
+30
+00:02:04,000 --> 00:02:07,000
+OK, so we really understood why we need map.
+
+31
+00:02:07,000 --> 00:02:14,000
+Now let's understand what specific different implementations of map interface have abstract map use
+
+32
+00:02:14,000 --> 00:02:21,000
+implementations for some of the methods of map interface, hash map implementation of map interface.
+
+33
+00:02:21,000 --> 00:02:27,000
+IT stores element using the mechanism of hash tables that guarantees constant amount of time for each
+
+34
+00:02:27,000 --> 00:02:29,000
+region and place elements.
+
+35
+00:02:29,000 --> 00:02:33,000
+That's why everyone loves hash map linked hash map.
+
+36
+00:02:33,000 --> 00:02:38,000
+Besides storing elements also memorized the sequence of adding entries in the map.
+
+37
+00:02:39,000 --> 00:02:46,000
+So the order of elements during the iteration is predictable because linked hash map maintains the list
+
+38
+00:02:46,000 --> 00:02:48,000
+ran through all of its entries.
+
+39
+00:02:48,000 --> 00:02:55,000
+If we need thread safe implementation of the map, we would opt for concurrent hash map that implements
+
+40
+00:02:55,000 --> 00:02:56,000
+concurrent map.
+
+41
+00:02:56,000 --> 00:02:58,000
+That in turn extends map interface.
+
+42
+00:02:59,000 --> 00:03:03,000
+We have a few more interfaces that extend map interface.
+
+43
+00:03:03,000 --> 00:03:10,000
+Zaya sorted map and navigable map sort of map provides ordering of a map based on its case.
+
+44
+00:03:11,000 --> 00:03:17,000
+The map is ordered according to the natural order of its keys that is defined according to implementation
+
+45
+00:03:17,000 --> 00:03:25,000
+of comparable interface or alternatively, Solin order may be defined by comparator navigable map extensors
+
+46
+00:03:25,000 --> 00:03:31,000
+map and provides developers with possibility to return the closest matches for given such targets.
+
+47
+00:03:31,000 --> 00:03:38,000
+The most popular implementations of this interface are three map and concurrence key place map for multithreaded
+
+48
+00:03:38,000 --> 00:03:39,000
+environment.
+
+49
+00:03:40,000 --> 00:03:42,000
+We also have APSA class dictionary.
+
+50
+00:03:42,000 --> 00:03:48,000
+How it is different from the map interface you can reclass was created in Java version one and supposed
+
+51
+00:03:48,000 --> 00:03:52,000
+to be a parent class for all types that map keys to values.
+
+52
+00:03:52,000 --> 00:03:58,000
+Since multiple inheritance in Java is not supported by the map interface was introduced in Java version
+
+53
+00:03:58,000 --> 00:03:58,000
+two.
+
+54
+00:03:59,000 --> 00:04:05,000
+So I would say that dictionary is an old version of map interface and that is considered as an obsolete
+
+55
+00:04:05,000 --> 00:04:07,000
+and use of map is preferred.
+
+56
+00:04:08,000 --> 00:04:13,000
+But still, you might be asked about dictionary during the interview and for your common Java literacy,
+
+57
+00:04:13,000 --> 00:04:15,000
+you have to be aware about it.
+
+58
+00:04:16,000 --> 00:04:21,000
+Hash table is a concrete class that extends the dictionary type and internments map interface.
+
+59
+00:04:22,000 --> 00:04:27,000
+It was considered as a thread safe version of hash map unless concurrent hash map was introduced in
+
+60
+00:04:27,000 --> 00:04:33,000
+Java version five, the synchronization mechanism is not so efficient as it is implemented in concurrent
+
+61
+00:04:33,000 --> 00:04:37,000
+Hashmat, in case you are not familiar with the trending topic.
+
+62
+00:04:37,000 --> 00:04:42,000
+That would explain the difference in the implementation of low interest rate and support in these classes.
+
+63
+00:04:42,000 --> 00:04:46,000
+In simple words, hash table closes the door in your home.
+
+64
+00:04:46,000 --> 00:04:53,000
+Concurrent hash map closes a separate doors in your home to allow everyone to walk around the home until
+
+65
+00:04:53,000 --> 00:04:54,000
+only one room is closed.
+
+66
+00:04:55,000 --> 00:05:01,000
+Can you feel the difference in implementation of concurrency support in these two classes and meet later
+
+67
+00:05:01,000 --> 00:05:02,000
+in the separate lessons?
+
+68
+00:05:02,000 --> 00:05:08,000
+We are going to learn multithreaded together and we will get back to a thread safe map implementations.
+
+69
+00:05:09,000 --> 00:05:11,000
+That's how MAP Iraqis look like.
+
+70
+00:05:11,000 --> 00:05:16,000
+Before we proceed with the details, I want to finish the topic of differences between hash map and
+
+71
+00:05:16,000 --> 00:05:17,000
+hash table.
+
+72
+00:05:18,000 --> 00:05:24,000
+So the first thing that is different we already discussed on MassArt and hash table are synchronized.
+
+73
+00:05:24,000 --> 00:05:28,000
+And that's why hash table is considered to be a thread safe map.
+
+74
+00:05:28,000 --> 00:05:33,000
+Hash table also does not allow news, a new case nor new values.
+
+75
+00:05:33,000 --> 00:05:39,000
+On the other hand, hash map allows us to store one key and multiple values.
+
+76
+00:05:39,000 --> 00:05:43,000
+Hash table is a legacy class, whereas hash map is newer.
+
+77
+00:05:44,000 --> 00:05:50,000
+And now I suggest opening the source code of map interface to learn that the communication and methods
+
+78
+00:05:50,000 --> 00:05:53,000
+of this interface here is map interface.
+
+79
+00:05:53,000 --> 00:06:00,000
+Pay attention to this interface doesn't extend iterable interface like collection while review and map
+
+80
+00:06:00,000 --> 00:06:00,000
+interface.
+
+81
+00:06:00,000 --> 00:06:06,000
+I'm going to use and work by saying entry, I would always mean the key value pair.
+
+82
+00:06:06,000 --> 00:06:11,000
+Is it clear, for example, size returns, amount of entries in the map.
+
+83
+00:06:12,000 --> 00:06:16,000
+In other words, a number of key value pairs is empty.
+
+84
+00:06:16,000 --> 00:06:18,000
+This is self-described Macit.
+
+85
+00:06:18,000 --> 00:06:25,000
+It checks whether the current map is empty or no, contains key verifies whether a map contains specific
+
+86
+00:06:25,000 --> 00:06:32,000
+contains value, similar method to check value in map, yet method to get value from the map we have
+
+87
+00:06:32,000 --> 00:06:32,000
+to use.
+
+88
+00:06:33,000 --> 00:06:37,000
+So we ask you to get Masset to retrieve our value.
+
+89
+00:06:37,000 --> 00:06:39,000
+There is no method in map.
+
+90
+00:06:39,000 --> 00:06:41,000
+Instead, we have put method.
+
+91
+00:06:41,000 --> 00:06:44,000
+We can put key value pair in map.
+
+92
+00:06:44,000 --> 00:06:47,000
+That's why put method takes two arguments.
+
+93
+00:06:48,000 --> 00:06:50,000
+Pay attention to the return tab here.
+
+94
+00:06:50,000 --> 00:06:56,000
+Imagine that you put in map integer value one and some customer reference type user as a value to the
+
+95
+00:06:56,000 --> 00:07:01,000
+map in this case, but will return now and now.
+
+96
+00:07:01,000 --> 00:07:07,000
+Imagine that you put new value but with the same key you call put MassArt again was integer value one
+
+97
+00:07:07,000 --> 00:07:09,000
+and new user object.
+
+98
+00:07:09,000 --> 00:07:15,000
+In this case, both method will return the value that was previously associated with the key.
+
+99
+00:07:15,000 --> 00:07:16,000
+That means previous user.
+
+100
+00:07:17,000 --> 00:07:18,000
+Does it make sense?
+
+101
+00:07:18,000 --> 00:07:24,000
+If you want to remove some entry from the map, you have to call remove Masset and Paskey as a method
+
+102
+00:07:24,000 --> 00:07:29,000
+argument map interface, declare methods for bulk operations, for example.
+
+103
+00:07:29,000 --> 00:07:33,000
+Put all method can add all entries from one object to another.
+
+104
+00:07:34,000 --> 00:07:35,000
+Clear message.
+
+105
+00:07:35,000 --> 00:07:38,000
+Remove all mappings from the current map object.
+
+106
+00:07:38,000 --> 00:07:44,000
+He has said massive returns contain the offset type that contains only keys from this map object.
+
+107
+00:07:44,000 --> 00:07:45,000
+Why set?
+
+108
+00:07:46,000 --> 00:07:48,000
+Because all keys are unique and map.
+
+109
+00:07:48,000 --> 00:07:51,000
+That's why I said type is returned.
+
+110
+00:07:51,000 --> 00:07:57,000
+In case we want to retrieve all whaler's from the map, we have to call values method that returns collection
+
+111
+00:07:57,000 --> 00:07:58,000
+of elements.
+
+112
+00:07:58,000 --> 00:07:59,000
+Why collection?
+
+113
+00:08:00,000 --> 00:08:03,000
+Because values are not unique and collection is returned.
+
+114
+00:08:04,000 --> 00:08:10,000
+Here's one more very useful method and set this massive return set of entries of this map.
+
+115
+00:08:10,000 --> 00:08:15,000
+Each key value pair is represented as a single object of type entry.
+
+116
+00:08:15,000 --> 00:08:17,000
+You really understand why set returned?
+
+117
+00:08:18,000 --> 00:08:23,000
+Because each key value pair is unique and three is in our interface in map.
+
+118
+00:08:24,000 --> 00:08:25,000
+Let's look at it.
+
+119
+00:08:25,000 --> 00:08:29,000
+Entry type has to match assets that are used more often than others.
+
+120
+00:08:29,000 --> 00:08:32,000
+They are yet key and get value.
+
+121
+00:08:32,000 --> 00:08:39,000
+For example, we can iterate over a set of entries in foreach loop and in the foreach loop body we can
+
+122
+00:08:39,000 --> 00:08:42,000
+use reference to the entry object together is a key or value.
+
+123
+00:08:43,000 --> 00:08:45,000
+It depends on what exactly we need.
+
+124
+00:08:45,000 --> 00:08:46,000
+According to our logic.
+
+125
+00:08:47,000 --> 00:08:51,000
+There are also other methods that data on my opinion are not used very often.
+
+126
+00:08:51,000 --> 00:08:53,000
+For example, set value.
+
+127
+00:08:53,000 --> 00:08:57,000
+It allows us to set value associated with the current key in the entry.
+
+128
+00:08:57,000 --> 00:09:03,000
+In my opinion, if there would be such need, I mean to update the value associated with a specific
+
+129
+00:09:03,000 --> 00:09:09,000
+key, most likely you want to do this with entry time, but instead we'll just call good method with
+
+130
+00:09:09,000 --> 00:09:12,000
+the same key on map object to update the value.
+
+131
+00:09:13,000 --> 00:09:18,000
+But probably one day you would face with the case that while iterating over entries, you need to implement
+
+132
+00:09:18,000 --> 00:09:24,000
+logic that under some specific conditions you have to update value that is associated with a specific
+
+133
+00:09:24,000 --> 00:09:25,000
+key.
+
+134
+00:09:25,000 --> 00:09:29,000
+And for this case, you already know what method can help you with that.
+
+135
+00:09:30,000 --> 00:09:32,000
+You can see equals and hash code.
+
+136
+00:09:32,000 --> 00:09:38,000
+You already know these methods and also entry has a few interesting static methods.
+
+137
+00:09:38,000 --> 00:09:41,000
+We are going to use them in our next lessons.
+
+138
+00:09:41,000 --> 00:09:41,000
+Right now.
+
+139
+00:09:41,000 --> 00:09:48,000
+Let me explain you and see what I say about we have comparing biochem assets at source entries by case
+
+140
+00:09:48,000 --> 00:09:55,000
+in case there implement comparable interface and we compare the parameter in case keys don't implement
+
+141
+00:09:55,000 --> 00:09:56,000
+comparable interface.
+
+142
+00:09:57,000 --> 00:10:03,000
+These methods return compared to that we can use to search and now attention to search our entries set,
+
+143
+00:10:04,000 --> 00:10:06,000
+but not elements in map bytes key.
+
+144
+00:10:07,000 --> 00:10:12,000
+And we also have comparing by value method that returns comparisons that can compare entries set by
+
+145
+00:10:12,000 --> 00:10:13,000
+values.
+
+146
+00:10:13,000 --> 00:10:16,000
+Imagine that you want to search your map by.
+
+147
+00:10:16,000 --> 00:10:21,000
+Well, to be honest, compared to that source, my case is not so cool.
+
+148
+00:10:21,000 --> 00:10:21,000
+Why?
+
+149
+00:10:22,000 --> 00:10:27,000
+Because we can create object of three map and put all elements from any map there and elements will
+
+150
+00:10:27,000 --> 00:10:31,000
+be sorted automatically by case, but sorting by various.
+
+151
+00:10:31,000 --> 00:10:36,000
+That is really helpful compared to now when we answer it, what entry type is.
+
+152
+00:10:36,000 --> 00:10:43,000
+Let's investigate what matters are left here in the map interface equals and hash good methods and.
+
+153
+00:10:44,000 --> 00:10:49,000
+The default message I described, for example, here is interesting and useful message.
+
+154
+00:10:49,000 --> 00:10:55,000
+Imagine that you need to get away from that, but you don't want to get new in case Element is absent
+
+155
+00:10:55,000 --> 00:10:56,000
+in map.
+
+156
+00:10:56,000 --> 00:11:03,000
+Instead, you would like to get some default value we can call yet or default to retrieve element by
+
+157
+00:11:03,000 --> 00:11:09,000
+key in case and market for such key present or to return default value in case there is no mapping for
+
+158
+00:11:09,000 --> 00:11:10,000
+such key.
+
+159
+00:11:10,000 --> 00:11:17,000
+Pay attention to the fact that in case we exist and values that is associated with this key is no value,
+
+160
+00:11:18,000 --> 00:11:19,000
+then no will be returned.
+
+161
+00:11:20,000 --> 00:11:24,000
+Default value will be returned only in case there is no such key in the map.
+
+162
+00:11:25,000 --> 00:11:30,000
+For each matsutake takes function that should be applied for each and every one will return functional
+
+163
+00:11:30,000 --> 00:11:31,000
+programming with Java.
+
+164
+00:11:32,000 --> 00:11:34,000
+That will show you how you can apply this method.
+
+165
+00:11:35,000 --> 00:11:41,000
+Replace all text functions that will be applied to each entry and each entry in turn will be substituted
+
+166
+00:11:41,000 --> 00:11:44,000
+with the result that will be returned by this function.
+
+167
+00:11:44,000 --> 00:11:51,000
+But if absent method should be used when you don't want to override the values that is already associated
+
+168
+00:11:51,000 --> 00:11:52,000
+with a specific key.
+
+169
+00:11:52,000 --> 00:11:59,000
+So new value will be put into the map only in case there is no entry with such key or keys associated
+
+170
+00:11:59,000 --> 00:11:59,000
+with no value.
+
+171
+00:12:00,000 --> 00:12:05,000
+The removal method can help you to remove entry by specifying the key value pair here.
+
+172
+00:12:05,000 --> 00:12:06,000
+Also replace MassArt.
+
+173
+00:12:07,000 --> 00:12:12,000
+They are different from Puth method because you can say that you want to replace Element only with a
+
+174
+00:12:12,000 --> 00:12:19,000
+specific key and with a specific value, or in case of overall that method only in case such key exists.
+
+175
+00:12:20,000 --> 00:12:24,000
+Comparative absence method allows you to compute value in case he is absent.
+
+176
+00:12:24,000 --> 00:12:30,000
+We can pass the keys that doesn't exist in map and function that can compute new value.
+
+177
+00:12:30,000 --> 00:12:34,000
+In case such care exists, the value won't be updated.
+
+178
+00:12:34,000 --> 00:12:41,000
+Compute if present method takes key and functions that can compute the value based on the current key
+
+179
+00:12:41,000 --> 00:12:47,000
+and previous value that is associated with it in case he exists and previous value is not.
+
+180
+00:12:47,000 --> 00:12:53,000
+Now, the result of the function will be associated with this key compute method.
+
+181
+00:12:53,000 --> 00:12:59,000
+Attempts to compute and mapping for the specified key and its current mapped value is there is no current
+
+182
+00:12:59,000 --> 00:12:59,000
+mapping.
+
+183
+00:13:00,000 --> 00:13:02,000
+Mersch method works in the following way.
+
+184
+00:13:03,000 --> 00:13:08,000
+It is a specified key, is not already associated with a value or is associated with.
+
+185
+00:13:08,000 --> 00:13:11,000
+Now associate it with the given no new value.
+
+186
+00:13:12,000 --> 00:13:19,000
+Otherwise replace the associated value with the results of the given remapping function or removes if
+
+187
+00:13:19,000 --> 00:13:21,000
+the result is now lost for assets.
+
+188
+00:13:21,000 --> 00:13:24,000
+Require knowledge of functional programming in Java.
+
+189
+00:13:24,000 --> 00:13:29,000
+That's why they will be reviewed in detail separately in the lessons about functional programming.
+
+190
+00:13:30,000 --> 00:13:37,000
+Right now it is enough high level understanding what this message do, and now we are done with all
+
+191
+00:13:37,000 --> 00:13:42,000
+default methods in my interface and it is time to review static methods in this interface.
+
+192
+00:13:43,000 --> 00:13:49,000
+Here we see overloaded static method with the name of this method, say here since Java version nine
+
+193
+00:13:49,000 --> 00:13:51,000
+and they can create immutable.
+
+194
+00:13:51,000 --> 00:13:56,000
+That also means unverifiable map that contains a limited number of mappings.
+
+195
+00:13:57,000 --> 00:14:02,000
+And you can see that the only difference between all of these methods is a number of mappings that it
+
+196
+00:14:02,000 --> 00:14:04,000
+takes as a parameter.
+
+197
+00:14:05,000 --> 00:14:10,000
+Here's a method that takes variable lengths, argument of type entry, and based on these creates and
+
+198
+00:14:10,000 --> 00:14:18,000
+modifiable map and remasters returns and modifiable entry type based on the key value pair that is passed
+
+199
+00:14:18,000 --> 00:14:20,000
+to the method, why this method is needed.
+
+200
+00:14:20,000 --> 00:14:26,000
+This method is needed, for example, for the previous method that we have just discussed, because
+
+201
+00:14:26,000 --> 00:14:31,000
+you want to eliminate the case when your entries changed because somebody got access to it by reference.
+
+202
+00:14:32,000 --> 00:14:35,000
+That's why you might want to create an modifiable entry first.
+
+203
+00:14:35,000 --> 00:14:37,000
+And this method will help you in that.
+
+204
+00:14:38,000 --> 00:14:41,000
+And the last but not least method for today is copy of.
+
+205
+00:14:42,000 --> 00:14:48,000
+If we want to create the copy of the map that nobody will be able to modify, we have to call this method
+
+206
+00:14:48,000 --> 00:14:52,000
+and parse the map that we want to copy as an argument to this method.
+
+207
+00:14:53,000 --> 00:14:55,000
+That's all method for map interface.
+
+208
+00:14:55,000 --> 00:15:00,000
+I believe that right now, you know, map interface even better than some senior software engineers.
+
+209
+00:15:01,000 --> 00:15:03,000
+Let's recap what we have learned today.
+
+210
+00:15:03,000 --> 00:15:05,000
+Today, we learned Map Iraqi.
+
+211
+00:15:05,000 --> 00:15:10,000
+We talked about features that are introduced in the implementations of map interface.
+
+212
+00:15:11,000 --> 00:15:14,000
+We also talked about source, map and navigable map.
+
+213
+00:15:14,000 --> 00:15:16,000
+We discussed what dictionary is.
+
+214
+00:15:17,000 --> 00:15:21,000
+Now, you know what the difference is between Hash Table and Hashmat.
+
+215
+00:15:21,000 --> 00:15:24,000
+After that, we learned methods of map interface.
+
+216
+00:15:25,000 --> 00:15:27,000
+We also learned what entry type is.
+
+217
+00:15:28,000 --> 00:15:29,000
+That's all what we have for today.
+
+218
+00:15:30,000 --> 00:15:31,000
+Thanks a lot for your attention.
+
+219
+00:15:31,000 --> 00:15:33,000
+See you in the next lesson.
+