Spring Boot Entity Creation Skill

This skill creates complete entity implementations following ActivityTracking project conventions.

When to Use

•Creating a new database entity
•Adding CRUD operations for a new domain object
•Need complete service + repository + controller setup

What This Skill Generates

•JPA Entity - Domain model with proper annotations
•Repository Interface - Spring Data JPA repository
•Service Class - Business logic layer with transactions
•REST Controller - API endpoints
•Unit Tests - Service layer tests
•Integration Tests - Repository tests with Testcontainers

Entity Creation Process

Step 1: Gather Requirements

Ask for:

•Entity name (e.g., "Report", "Category", "Note")
•Fields and types
•Relationships to other entities
•Business rules and validation
•API endpoints needed

Step 2: Generate Entity

java

package com.ammons.taskactivity.entity;

/**
 * Entity representing [description of what this represents].
 *
 * @author Dean Ammons
 * @version 1.0
 * @since January 2026
 */
@Entity
@Table(name = "table_name")
@Builder
@NoArgsConstructor
@AllArgsConstructor
public class MyEntity {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(name = "field_name", nullable = false)
    @NotBlank(message = "Field name is required")
    private String fieldName;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "user_id", nullable = false)
    private User user;

    @CreationTimestamp
    @Column(name = "created_at", nullable = false, updatable = false)
    private LocalDateTime createdAt;

    @UpdateTimestamp
    @Column(name = "updated_at", nullable = false)
    private LocalDateTime updatedAt;

    // Getters and setters with explicit access modifiers
    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    // ... rest of getters/setters
}

Step 3: Generate Repository

java

package com.ammons.taskactivity.repository;

/**
 * Repository interface for MyEntity data access operations.
 *
 * @author Dean Ammons
 * @version 1.0
 * @since January 2026
 */
@Repository
public interface MyEntityRepository extends JpaRepository<MyEntity, Long> {

    List<MyEntity> findByUserId(Long userId);

    Page<MyEntity> findByUserId(Long userId, Pageable pageable);

    @Query("SELECT e FROM MyEntity e WHERE e.user.id = :userId AND e.fieldName LIKE %:keyword%")
    List<MyEntity> searchByUserAndKeyword(
        @Param("userId") Long userId,
        @Param("keyword") String keyword
    );
}

Step 4: Generate Service

java

package com.ammons.taskactivity.service;

/**
 * Service layer for managing MyEntity business logic.
 * Handles CRUD operations, validation, and business rules.
 *
 * @author Dean Ammons
 * @version 1.0
 * @since January 2026
 */
@Service
@Transactional
public class MyEntityService {

    private final MyEntityRepository repository;
    private final UserService userService;

    public MyEntityService(MyEntityRepository repository, UserService userService) {
        this.repository = repository;
        this.userService = userService;
    }

    /**
     * Retrieves all entities for a specific user.
     *
     * @param userId The user's unique identifier
     * @return List of entities belonging to the user
     */
    @Transactional(readOnly = true)
    public List<MyEntity> findByUserId(Long userId) {
        return repository.findByUserId(userId);
    }

    /**
     * Creates or updates an entity.
     *
     * @param entity The entity to save
     * @return The saved entity with generated ID
     * @throws ValidationException if validation fails
     */
    public MyEntity save(MyEntity entity) {
        validateEntity(entity);
        return repository.save(entity);
    }

    /**
     * Deletes an entity by ID.
     *
     * @param id The entity's unique identifier
     * @throws ResourceNotFoundException if entity not found
     */
    public void deleteById(Long id) {
        if (!repository.existsById(id)) {
            throw new ResourceNotFoundException("Entity not found with id: " + id);
        }
        repository.deleteById(id);
    }

    private void validateEntity(MyEntity entity) {
        if (entity.getFieldName() == null || entity.getFieldName().trim().isEmpty()) {
            throw new ValidationException("Field name is required");
        }
    }
}

Step 5: Generate REST Controller

java

package com.ammons.taskactivity.controller;

/**
 * REST API controller for MyEntity operations.
 * Provides CRUD endpoints with proper HTTP semantics.
 *
 * @author Dean Ammons
 * @version 1.0
 * @since January 2026
 */
@RestController
@RequestMapping("/api/myentities")
@CrossOrigin(origins = "*")
public class MyEntityController {

    private final MyEntityService service;

    public MyEntityController(MyEntityService service) {
        this.service = service;
    }

    @GetMapping
    public ResponseEntity<List<MyEntity>> getAll(Principal principal) {
        Long userId = getUserIdFromPrincipal(principal);
        List<MyEntity> entities = service.findByUserId(userId);
        return ResponseEntity.ok(entities);
    }

    @GetMapping("/{id}")
    public ResponseEntity<MyEntity> getById(@PathVariable Long id) {
        return service.findById(id)
            .map(ResponseEntity::ok)
            .orElse(ResponseEntity.notFound().build());
    }

    @PostMapping
    public ResponseEntity<MyEntity> create(
            @Valid @RequestBody MyEntity entity,
            Principal principal) {
        Long userId = getUserIdFromPrincipal(principal);
        entity.setUser(new User(userId));
        MyEntity saved = service.save(entity);
        return ResponseEntity.status(HttpStatus.CREATED).body(saved);
    }

    @PutMapping("/{id}")
    public ResponseEntity<MyEntity> update(
            @PathVariable Long id,
            @Valid @RequestBody MyEntity entity) {
        return service.findById(id)
            .map(existing -> {
                entity.setId(id);
                MyEntity updated = service.save(entity);
                return ResponseEntity.ok(updated);
            })
            .orElse(ResponseEntity.notFound().build());
    }

    @DeleteMapping("/{id}")
    public ResponseEntity<Void> delete(@PathVariable Long id) {
        try {
            service.deleteById(id);
            return ResponseEntity.noContent().build();
        } catch (ResourceNotFoundException e) {
            return ResponseEntity.notFound().build();
        }
    }

    private Long getUserIdFromPrincipal(Principal principal) {
        // Extract user ID from JWT principal
        return 1L;  // Implement based on your auth setup
    }
}

Step 6: Generate Tests

java

/**
 * Unit tests for MyEntityService business logic.
 *
 * @author Dean Ammons
 * @version 1.0
 * @since January 2026
 */
@ExtendWith(MockitoExtension.class)
class MyEntityServiceTest {

    @Mock
    private MyEntityRepository repository;

    @Mock
    private UserService userService;

    @InjectMocks
    private MyEntityService service;

    @Test
    @DisplayName("Should save entity successfully")
    void shouldSaveEntity() {
        // Given
        MyEntity entity = MyEntity.builder()
            .fieldName("Test")
            .build();
        when(repository.save(any())).thenReturn(entity);

        // When
        MyEntity saved = service.save(entity);

        // Then
        assertNotNull(saved);
        verify(repository).save(entity);
    }
}

Project Conventions Enforced

✅ Explicit Access Modifiers - Every class, method, field ✅ JavaDoc - File-level with @author, @version, @since ✅ Constructor Injection - No field injection ✅ Validation - Bean Validation annotations ✅ Transactions - @Transactional on service methods ✅ Error Handling - Proper exception types ✅ Testing - Unit + integration tests

Database Migration

After creating entity, remind to:

•Add table to schema.sql for fresh installs
•Create migration script for existing databases
•Update production database

sql

CREATE TABLE IF NOT EXISTS my_entities (
    id BIGSERIAL PRIMARY KEY,
    field_name VARCHAR(255) NOT NULL,
    user_id BIGINT NOT NULL REFERENCES users(id),
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

CREATE INDEX idx_my_entities_user_id ON my_entities(user_id);

Angular Service (Optional)

typescript

/**
 * Service for managing MyEntity operations via REST API.
 *
 * Author: Dean Ammons
 * Date: January 2026
 */
@Injectable({ providedIn: "root" })
export class MyEntityService {
    private apiUrl = "/api/myentities";

    constructor(private http: HttpClient) {}

    getAll(): Observable<MyEntity[]> {
        return this.http.get<MyEntity[]>(this.apiUrl);
    }

    create(entity: MyEntity): Observable<MyEntity> {
        return this.http.post<MyEntity>(this.apiUrl, entity);
    }

    update(id: number, entity: MyEntity): Observable<MyEntity> {
        return this.http.put<MyEntity>(`${this.apiUrl}/${id}`, entity);
    }

    delete(id: number): Observable<void> {
        return this.http.delete<void>(`${this.apiUrl}/${id}`);
    }
}

Checklist

Memory Bank References

•Check ai/java-conventions.md for coding standards
•Check ai/common-patterns.md for templates
•Check ai/architecture-patterns.md for entity patterns