feat: implement feature to Get Members of an Organisation.

src/main/java/hng_java_boilerplate/organisation/controller/OrganisationController.java

@@ -33,6 +33,18 @@ public ResponseEntity<CreateOrganisationResponseDto> createOrganisation(
         );
     }
 
+    @GetMapping("/{org_id}/users")
+    public ResponseEntity<?> getOrganisationUsers(@PathVariable(name = "org_id") String orgId,
+                                              @RequestParam(name = "page", defaultValue = "0") int page,
+                                              @RequestParam(name = "size", defaultValue = "10") int pageSize) {
+        try {
+            return ResponseEntity.ok(organisationService.getOrganisationUsers(orgId, page, pageSize));
+        } catch (Exception e) {
+            return ResponseEntity.badRequest().body(e.getMessage());
+        }
+    }
+}
+
     @PostMapping("/{organisationId}/users")
     public ResponseEntity<?> addUserToOrganisation(
             @PathVariable("organisationId") String organisationId,
@@ -50,4 +62,4 @@ public ResponseEntity<?> getOrganisationById(@PathVariable String organisationId
         Organisation organisation = organisationService.getOrganisationById(organisationId);
         return ResponseEntity.ok(organisation);
     }
-}
+}

src/main/java/hng_java_boilerplate/organisation/dto/ApiResponseDTO.java

@@ -0,0 +1,14 @@
+package hng_java_boilerplate.organisation.dto;
+
+import com.fasterxml.jackson.annotation.JsonProperty;
+import lombok.Builder;
+import lombok.Data;
+
+@Builder
+@Data
+public class ApiResponseDTO {
+    @JsonProperty("status_code")
+    private int statusCode;
+    private String message;
+    private Object data;
+}

src/main/java/hng_java_boilerplate/organisation/service/OrganisationService.java

@@ -1,19 +1,27 @@
 package hng_java_boilerplate.organisation.service;
 
 import hng_java_boilerplate.activitylog.service.ActivityLogService;
+import hng_java_boilerplate.organisation.dto.ApiResponseDTO;
 import hng_java_boilerplate.exception.NotFoundException;
 import hng_java_boilerplate.organisation.dto.CreateOrganisationRequestDto;
 import hng_java_boilerplate.organisation.dto.CreateOrganisationResponseDto;
 import hng_java_boilerplate.organisation.dto.DataDto;
 import hng_java_boilerplate.organisation.entity.Organisation;
 import hng_java_boilerplate.organisation.exception.OrganisationNameAlreadyExistsException;
 import hng_java_boilerplate.organisation.repository.OrganisationRepository;
+import hng_java_boilerplate.user.dto.request.GetUserDto;
 import hng_java_boilerplate.user.entity.User;
 import hng_java_boilerplate.user.repository.UserRepository;
 import lombok.RequiredArgsConstructor;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.PageRequest;
+import org.springframework.data.domain.Pageable;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
 import org.springframework.security.core.Authentication;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
+import org.springframework.web.server.ResponseStatusException;
 
 import java.time.LocalDateTime;
 import java.util.List;
@@ -82,8 +90,41 @@ public CreateOrganisationResponseDto create(
                 .build();
     }
 
+    public ResponseEntity<ApiResponseDTO> getOrganisationUsers(String orgId, int page, int pageSize) {
+        organisationRepository.findById(orgId)
+                .orElseThrow(() -> new ResponseStatusException(HttpStatus.NOT_FOUND, "Organisation not found"));
+
+        Pageable pageable = PageRequest.of(page, pageSize);
+        Page<User> users = userRepository.findByOrganisations_Id(orgId, pageable);
+
+        if (users.isEmpty()) {
+            return ResponseEntity.status(HttpStatus.NOT_FOUND)
+                    .body(ApiResponseDTO.builder()
+                            .statusCode(400)
+                            .message("No users found for organisation with ID: " + orgId)
+                            .data(null)
+                            .build());
+        }
+
+        List<GetUserDto> userDtoList = users.getContent().stream()
+                .map(user -> GetUserDto.builder()
+                        .id(user.getId())
+                        .name(user.getName())
+                        .email(user.getEmail())
+                        .build())
+                .toList();
+
+        return ResponseEntity.status(HttpStatus.OK)
+                .body(ApiResponseDTO.builder()
+                        .statusCode(200)
+                        .message("Users retrieved successfully for organisation with ID: " + orgId)
+                        .data(userDtoList)
+                        .build());
+    }
+}
+
     public Organisation getOrganisationById(String organisationId) {
         return organisationRepository.findById(organisationId)
                 .orElseThrow(() -> new NotFoundException("Organization not found"));
     }
-}
+}

src/main/java/hng_java_boilerplate/user/repository/UserRepository.java

@@ -2,7 +2,10 @@
 
 import hng_java_boilerplate.user.entity.User;
 import hng_java_boilerplate.user.enums.Role;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.Pageable;
 import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.web.bind.annotation.RequestParam;
 
 import java.util.List;
 import java.util.Optional;
@@ -17,4 +20,6 @@ public interface UserRepository extends JpaRepository<User, String> {
     void deleteByEmail(String mail);
 
     List<User> findUserByUserRole(Role role);
+
+    Page<User> findByOrganisations_Id( String orgId, Pageable pageable);
 }

src/test/java/hng_java_boilerplate/organisation/service/OrganisationServiceTest.java

@@ -2,6 +2,7 @@
 
 import hng_java_boilerplate.exception.NotFoundException;
 import hng_java_boilerplate.activitylog.service.ActivityLogService;
+import hng_java_boilerplate.organisation.dto.ApiResponseDTO;
 import hng_java_boilerplate.organisation.dto.CreateOrganisationRequestDto;
 import hng_java_boilerplate.organisation.dto.CreateOrganisationResponseDto;
 import hng_java_boilerplate.organisation.entity.Organisation;
@@ -10,6 +11,7 @@
 import hng_java_boilerplate.organisation.exception.OrganisationNameAlreadyExistsException;
 import hng_java_boilerplate.organisation.exception.ValidationError;
 import hng_java_boilerplate.organisation.repository.OrganisationRepository;
+import hng_java_boilerplate.user.dto.request.GetUserDto;
 import hng_java_boilerplate.user.entity.User;
 import hng_java_boilerplate.user.repository.UserRepository;
 import org.junit.jupiter.api.BeforeEach;
@@ -18,6 +20,9 @@
 import org.mockito.InjectMocks;
 import org.mockito.Mock;
 import org.mockito.junit.jupiter.MockitoExtension;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.PageImpl;
+import org.springframework.data.domain.PageRequest;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
 import org.springframework.security.core.Authentication;
@@ -53,6 +58,8 @@ class OrganisationServiceTest {
     private User user;
     private Organisation organisation;
 
+    private Organisation organisation;
+
     @BeforeEach
     void setUp() {
         orgRequest = new CreateOrganisationRequestDto(
@@ -71,6 +78,11 @@ void setUp() {
         organisation = new Organisation();
         organisation.setId("org-123");
         organisation.setName("Test Organisation");
+
+        user = new User();
+        user.setId("user-123");
+        user.setName("John Doe");
+        user.setEmail("[email protected]");
         organisation.setDescription("A test org");
     }
 
@@ -137,7 +149,58 @@ void create_shouldThrowValidationException_whenRequestIsInvalid() {
     }
 
     @Test
-    void getOrganisationById_shouldReturnOrganisation_whenOrganisationExists() {
+    void getOrganisationUsers_shouldReturnNotFound_whenOrganisationDoesNotExist() {
+        when(organisationRepository.findById("org-123")).thenReturn(Optional.empty());
+
+        Exception exception = assertThrows(Exception.class, () ->
+                organisationService.getOrganisationUsers("org-123", 0, 10)
+        );
+
+        assertEquals("404 NOT_FOUND \"Organisation not found\"", exception.getMessage());
+        verify(organisationRepository, times(1)).findById("org-123");
+    }
+
+    @Test
+    void getOrganisationUsers_shouldReturnNotFound_whenNoUsersFound() {
+        when(organisationRepository.findById("org-123")).thenReturn(Optional.of(organisation));
+        when(userRepository.findByOrganisations_Id("org-123", PageRequest.of(0, 10)))
+                .thenReturn(Page.empty());
+
+        ResponseEntity<ApiResponseDTO> response = organisationService.getOrganisationUsers("org-123", 0, 10);
+
+        assertNotNull(response);
+        assertEquals(HttpStatus.NOT_FOUND, response.getStatusCode());
+        assertEquals(400, response.getBody().getStatusCode());
+        assertEquals("No users found for organisation with ID: org-123", response.getBody().getMessage());
+        assertNull(response.getBody().getData());
+    }
+
+    @Test
+    void getOrganisationUsers_shouldReturnUsers_whenUsersExist() {
+        when(organisationRepository.findById("org-123")).thenReturn(Optional.of(organisation));
+        List<User> users = List.of(user);
+        Page<User> userPage = new PageImpl<>(users);
+        when(userRepository.findByOrganisations_Id("org-123", PageRequest.of(0, 10)))
+                .thenReturn(userPage);
+
+        ResponseEntity<ApiResponseDTO> response = organisationService.getOrganisationUsers("org-123", 0, 10);
+
+        assertNotNull(response);
+        assertEquals(HttpStatus.OK, response.getStatusCode());
+        assertEquals(200, response.getBody().getStatusCode());
+        assertEquals("Users retrieved successfully for organisation with ID: org-123", response.getBody().getMessage());
+        assertNotNull(response.getBody().getData());
+
+        List<GetUserDto> userDtos = (List<GetUserDto>) response.getBody().getData();
+        assertEquals(1, userDtos.size());
+        assertEquals("user-123", userDtos.get(0).getId());
+        assertEquals("John Doe", userDtos.get(0).getName());
+        assertEquals("[email protected]", userDtos.get(0).getEmail());
+    }
+
+}
+
+void getOrganisationById_shouldReturnOrganisation_whenOrganisationExists() {
         String organisationId = "org-123";
         when(organisationRepository.findById(organisationId)).thenReturn(Optional.of(organisation));