상품

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상품 도메인 개발

@Entity
@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(name = "dtype")
@Getter @Setter
public abstract class Item {
    @Id @GeneratedValue
    @Column(name = "item_id")
    private Long id;
    private String name;
    private int price;
    private int stockQuantity;

    @ManyToMany(mappedBy = "items")
    private List<Category> categories = new ArrayList<Category>();
    //==비즈니스 로직==//
    public void addStock(int quantity) {
        this.stockQuantity += quantity;
    }
    public void removeStock(int quantity) {
        int restStock = this.stockQuantity - quantity;
        if (restStock < 0) {
            throw new NotEnoughStockException("need more stock");
        }
        this.stockQuantity = restStock;
    }
}

예외 추가 (NotEnoughStockException)

 public class NotEnoughStockException extends RuntimeException {
    public NotEnoughStockException() {
    }
    public NotEnoughStockException(String message) {
        super(message);
    }
    public NotEnoughStockException(String message, Throwable cause) {
        super(message, cause);
    }   
    public NotEnoughStockException(Throwable cause) {
        super(cause);
    } 
}

상품 리포지토리

@Repository
@RequiredArgsConstructor
public class ItemRepository {
    private final EntityManager em;
    public void save(Item item) {
        if (item.getId() == null) {
            em.persist(item);
        } else {
            em.merge(item);
        }
    }
    public Item findOne(Long id) {
        return em.find(Item.class, id);
    }
    public List<Item> findAll() {
        return em.createQuery("select i from Item i",Item.class).getResultList();
    }
}

em.merge(item) : id가 있으면 데이터베이스에 저장된 엔티티를 수정한다.

상품 서비스

상품 서비스는 그저 상품 리포지토리에 위임을 하는 역할이다.

@Service
@Transactional(readOnly = true)
@RequiredArgsConstructor
public class ItemService {
    private final ItemRepository itemRepository;
    @Transactional
    public void saveItem(Item item) {
        itemRepository.save(item);
    }
    public List<Item> findItems() {
        return itemRepository.findAll();
    }
    public Item findOne(Long itemId) {
        return itemRepository.findOne(itemId);
    } 
}

주문

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복잡한 로직들이 많다 정신 차리자

주문 엔티티

@Entity
@Table(name = "orders")
@Getter @Setter
public class Order {
  @Id @GeneratedValue
  @Column(name = "order_id")
  private Long id;

  @ManyToOne(fetch = FetchType.LAZY) 
  @JoinColumn(name = "member_id") 
  private Member member; //주문 회원

  @OneToMany(mappedBy = "order", cascade = CascadeType.ALL)
  private List<OrderItem> orderItems = new ArrayList<>();

  @OneToOne(cascade = CascadeType.ALL, fetch = FetchType.LAZY) 
  @JoinColumn(name = "delivery_id")
  private Delivery delivery; //배송정보

  private LocalDateTime orderDate; //주문시간 @Enumerated(EnumType.STRING)
  private OrderStatus status; //주문상태 [ORDER, CANCEL]
  //==연관관계 메서드==//
  public void setMember(Member member) {
      this.member = member;
      member.getOrders().add(this);
  }
  public void addOrderItem(OrderItem orderItem) {
      orderItems.add(orderItem);
      orderItem.setOrder(this);
  }
  public void setDelivery(Delivery delivery) {
      this.delivery = delivery;
      delivery.setOrder(this);
  }
  //==생성 메서드==//
  public static Order createOrder(Member member, Delivery delivery, OrderItem... orderItems) {
    Order order = new Order();
    order.setMember(member);
    order.setDelivery(delivery);
    for (OrderItem orderItem : orderItems) {
        order.addOrderItem(orderItem);
    }
    order.setStatus(OrderStatus.ORDER);
    order.setOrderDate(LocalDateTime.now());
    return order;
  }
  //==비즈니스 로직==//
  /** 주문 취소 */
  public void cancel() {
    if (delivery.getStatus() == DeliveryStatus.COMP) {
      throw new IllegalStateException("이미 배송완료된 상품은 취소가 불가능합니다."); 
    }
    this.setStatus(OrderStatus.CANCEL);
    for (OrderItem orderItem : orderItems) {
      orderItem.cancel();
    }
  }
  //==조회 로직==//
  /**전체 주문 가격 조회*/ 
    public int getTotalPrice() {
      int totalPrice = 0;
      for (OrderItem orderItem : orderItems) {
          totalPrice += orderItem.getTotalPrice();
      }
      return totalPrice;
    }
  }