Add RoleCountProjection, fix performance of getRoleCounts()

src/main/java/com/attendenceSystem/module/user/provider/UserStatisticProvider.java

@@ -1,6 +1,5 @@
 package com.attendenceSystem.module.user.provider;
 
-import java.util.Arrays;
 import java.util.Map;
 import java.util.stream.Collectors;
 
@@ -30,8 +29,13 @@ public class UserStatisticProvider {
     }
 
     public Map<String, Long> getRoleCounts() {
-        return Arrays.stream(Role.values())
-                .collect(Collectors.toMap(Enum::name, userRepository::countByRole));
+        return userRepository.countUsersGroupByRole()
+                .stream()
+                .filter(p -> p != null && p.getRole() != null)
+                .collect(
+                        Collectors.toMap(
+                                p -> p.getRole().name(),
+                                p -> p.getCount()));
     }
-    
+
 }

src/main/java/com/attendenceSystem/module/user/repository/UserRepository.java

@@ -16,9 +16,11 @@ import com.attendenceSystem.module.user.entity.enums.Department;
 import com.attendenceSystem.module.user.entity.enums.Specialization;
 import com.attendenceSystem.module.user.entity.enums.Role;
 import com.attendenceSystem.module.user.entity.enums.Status;
+import com.attendenceSystem.module.user.repository.projection.RoleCountProjection;
 
 @Repository
 public interface UserRepository extends JpaRepository<User, Long> {
+
     Optional<User> findById(Long id);
 
     Optional<User> findUserByUsername(String username);
@@ -60,4 +62,7 @@ public interface UserRepository extends JpaRepository<User, Long> {
     List<UserSimpleResponse> findFullNameByDepartmentAndRoleNot(
             @Param("department") Department department,
             @Param("role") Role role);
+
+    @Query("SELECT u.role AS role, COUNT(u) AS count FROM User u GROUP BY u.role")
+    List<RoleCountProjection> countUsersGroupByRole();
 }

src/main/java/com/attendenceSystem/module/user/repository/projection/RoleCountProjection.java

@@ -0,0 +1,10 @@
+package com.attendenceSystem.module.user.repository.projection;
+
+import com.attendenceSystem.module.user.entity.enums.Role;
+
+public interface RoleCountProjection {
+    Role getRole();
+
+    Long getCount();
+
+}