[volume-3] 도메인 모델링 및 구현

CLAUDE.md

@@ -58,14 +58,18 @@ infrastructure/  → JpaRepository 구현체
 support/error/   → CoreException, ErrorType (에러 코드 enum)
 ```
 
-- Repository 패턴: domain에 인터페이스, infrastructure에 구현체
+- 본 프로젝트는 레이어드 아키텍처를 따르며, DIP (의존성 역전 원칙) 을 준수합니다.
+  - Repository 패턴: domain에 인터페이스, infrastructure에 구현체
+- API request, response DTO와 응용 레이어의 DTO는 분리해 작성
 - Facade 패턴: application 레이어에서 여러 도메인 서비스 조합
 - API 버전닝: `/api/v1/` 경로 기반
 - 글로벌 예외 처리: `ApiControllerAdvice`에서 `CoreException` → `ApiResponse` 변환
 
-### BaseEntity (modules/jpa)
-
-모든 엔티티의 부모 클래스. Auto-increment ID, `createdAt`/`updatedAt`/`deletedAt` 자동 관리, `delete()`/`restore()` 소프트 삭제 지원.
+#### 도메인 & 객체 설계 전략
+- 도메인 객체는 비즈니스 규칙을 캡슐화해야 합니다.
+- 애플리케이션 서비스는 서로 다른 도메인을 조립해, 도메인 로직을 조정하여 기능을 제공해야 합니다.
+- 규칙이 여러 서비스에 나타나면 도메인 객체에 속할 가능성이 높습니다.
+- 각 기능에 대한 책임과 결합도에 대해 개발자의 의도를 확인하고 개발을 진행합니다.
 
 ## Testing
 
@@ -118,3 +122,5 @@ support/error/   → CoreException, ErrorType (에러 코드 enum)
 - 불필요한 코드 제거 및 품질 개선
 - 객체지향적 코드 작성, 성능 최적화
 - 모든 테스트 케이스가 통과해야 함
+
+

apps/commerce-api/src/main/java/com/loopers/application/like/LikeFacade.java

@@ -0,0 +1,26 @@
+package com.loopers.application.like;
+
+import com.loopers.domain.like.LikeService;
+import com.loopers.domain.product.ProductService;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+@Service
+@RequiredArgsConstructor
+@Transactional
+public class LikeFacade {
+
+    private final LikeService likeService;
+    private final ProductService productService;
+
+    public void toggleLike(Long productId, Long userId) {
+        if (likeService.isLiked(productId, userId)) {
+            likeService.unlike(productId, userId);
+            productService.decreaseLikeCount(productId);
+        } else {
+            likeService.like(productId, userId);
+            productService.increaseLikeCount(productId);
+        }
+    }
+}

apps/commerce-api/src/main/java/com/loopers/application/order/OrderCommand.java

@@ -0,0 +1,9 @@
+package com.loopers.application.order;
+
+import java.util.Map;
+
+public record OrderCommand(
+    Long userId,
+    Map<Long, Integer> productQuantities
+) {
+}

apps/commerce-api/src/main/java/com/loopers/application/order/OrderFacade.java

@@ -0,0 +1,42 @@
+package com.loopers.application.order;
+
+import com.loopers.domain.order.Order;
+import com.loopers.domain.order.OrderItemSpec;
+import com.loopers.domain.order.OrderService;
+import com.loopers.domain.product.Product;
+import com.loopers.domain.product.ProductService;
+import java.util.ArrayList;
+import java.util.List;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+@Service
+@RequiredArgsConstructor
+@Transactional
+public class OrderFacade {
+
+    private final ProductService productService;
+    private final OrderService orderService;
+
+    public OrderInfo order(OrderCommand command) {
+        List<Long> productIds = new ArrayList<>(command.productQuantities().keySet());
+        List<Product> products = productService.getByIds(productIds);
+
+        products.forEach(product ->
+            productService.decreaseStock(product.getId(), command.productQuantities().get(product.getId())));
+
+        List<OrderItemSpec> itemSpecs = products.stream()
+            .map(product -> new OrderItemSpec(
+                product.getId(),
+                product.getPrice(),
+                command.productQuantities().get(product.getId())
+            ))
+            .toList();
+
+        // 도메인 서비스에 주문 애그리거트 생성/저장 위임
+        Order savedOrder = orderService.placeOrder(command.userId(), itemSpecs);
+
+        return OrderInfo.from(savedOrder);
+    }
+}

apps/commerce-api/src/main/java/com/loopers/application/order/OrderInfo.java

@@ -0,0 +1,23 @@
+package com.loopers.application.order;
+
+import com.loopers.domain.order.Order;
+import com.loopers.domain.order.OrderStatus;
+import java.time.ZonedDateTime;
+
+public record OrderInfo(
+    Long id,
+    Long userId,
+    OrderStatus status,
+    Integer totalPrice,
+    ZonedDateTime orderDt
+) {
+    public static OrderInfo from(Order order) {
+        return new OrderInfo(
+            order.getId(),
+            order.getRefUserId(),
+            order.getStatus(),
+            order.getTotalPrice().value(),
+            order.getOrderDt()
+        );
+    }
+}

apps/commerce-api/src/main/java/com/loopers/application/product/CreateProductCommand.java

@@ -0,0 +1,14 @@
+package com.loopers.application.product;
+
+import java.util.Map;
+
+public record CreateProductCommand(
+    Map<Long, ProductItem> products
+) {
+    public record ProductItem(
+        String name,
+        Integer price,
+        Integer stock
+    ) {
+    }
+}

apps/commerce-api/src/main/java/com/loopers/application/product/ProductFacade.java

@@ -0,0 +1,72 @@
+package com.loopers.application.product;
+
+import com.loopers.domain.brand.Brand;
+import com.loopers.domain.brand.BrandService;
+import com.loopers.domain.product.CreateProductRequest;
+import com.loopers.domain.product.Product;
+import com.loopers.domain.product.ProductSearchCondition;
+import com.loopers.domain.product.ProductService;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+@Service
+@RequiredArgsConstructor
+@Transactional
+public class ProductFacade {
+
+    private final BrandService brandService;
+    private final ProductService productService;
+
+    public List<ProductInfo> createProducts(CreateProductCommand command) {
+        command.products().keySet().forEach(brandService::getById);
+
+        Map<Long, CreateProductRequest> domainRequest = new HashMap<>();
+        command.products().forEach((brandId, item) -> {
+            domainRequest.put(brandId, new CreateProductRequest(
+                item.name(),
+                item.price(),
+                item.stock()
+            ));
+        });
+
+        List<Product> products = productService.createProducts(domainRequest);
+        return products.stream()
+            .map(product -> {
+                Brand brand = brandService.getById(product.getRefBrandId());
+                return ProductInfo.of(product, brand);
+            })
+            .toList();
+    }
+
+    @Transactional(readOnly = true)
+    public ProductInfo getProduct(Long productId) {
+        Product product = productService.getById(productId);
+        Brand brand = brandService.getById(product.getRefBrandId());
+        return ProductInfo.of(product, brand);
+    }
+
+    @Transactional(readOnly = true)
+    public List<ProductInfo> getProducts(ProductSearchCommand command) {
+        if (command.hasBrandId()) {
+            brandService.getById(command.brandId());
+        }
+
+        ProductSearchCondition condition = new ProductSearchCondition(
+            command.brandId(),
+            command.sortType(),
+            command.page(),
+            command.size()
+        );
+
+        return productService.findProducts(condition).stream()
+            .map(product -> {
+                Brand brand = brandService.getById(product.getRefBrandId());
+                return ProductInfo.of(product, brand);
+            })
+            .toList();
+    }
+}

apps/commerce-api/src/main/java/com/loopers/application/product/ProductInfo.java

@@ -0,0 +1,29 @@
+package com.loopers.application.product;
+
+import com.loopers.domain.brand.Brand;
+import com.loopers.domain.product.Product;
+
+public record ProductInfo(
+    Long id,
+    String name,
+    Integer price,
+    Integer stock,
+    Integer likeCount,
+    Long brandId,
+    String brandName,
+    String brandDescription
+) {
+
+    public static ProductInfo of(Product product, Brand brand) {
+        return new ProductInfo(
+            product.getId(),
+            product.getName(),
+            product.getPrice().value(),
+            product.getStock(),
+            product.getLikeCount(),
+            brand.getId(),
+            brand.getName(),
+            brand.getDescription()
+        );
+    }
+}

apps/commerce-api/src/main/java/com/loopers/application/product/ProductSearchCommand.java

@@ -0,0 +1,14 @@
+package com.loopers.application.product;
+
+import com.loopers.domain.product.ProductSortType;
+
+public record ProductSearchCommand(
+    Long brandId,
+    ProductSortType sortType,
+    int page,
+    int size
+) {
+    public boolean hasBrandId() {
+        return brandId != null;
+    }
+}

apps/commerce-api/src/main/java/com/loopers/domain/brand/Brand.java

@@ -0,0 +1,52 @@
+package com.loopers.domain.brand;
+
+import com.loopers.support.error.CoreException;
+import com.loopers.support.error.ErrorMessage;
+import com.loopers.support.error.ErrorType;
+
+/**
+ *  브랜드 도메인 객체
+ */
+public class Brand {
+
+    private final Long id;
+    private String name;
+    private String description;
+
+    private Brand(Long id, String name, String description) {
+        this.id = id;
+        this.name = name;
+        this.description = description;
+    }
+
+    public static Brand create(Long id, String name, String description) {
+        validateName(name);
+
+        return new Brand(id, name, description);
+    }
+
+    private static void validateName(String name) {
+        if (name == null || name.isBlank()) {
+            throw new CoreException(ErrorType.BAD_REQUEST, ErrorMessage.Brand.BRAND_NAME_REQUIRED);
+        }
+    }
+
+    public void update(String name, String description) {
+        validateName(name);
+
+        this.name = name;
+        this.description = description;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public String getDescription() {
+        return description;
+    }
+}

apps/commerce-api/src/main/java/com/loopers/domain/brand/BrandRepository.java

@@ -0,0 +1,11 @@
+package com.loopers.domain.brand;
+
+import java.util.Optional;
+
+public interface BrandRepository {
+
+    Brand create(Brand brand);
+    Brand update(Brand brand);
+    Optional<Brand> findById(Long id);
+    boolean existsById(Long id);
+}

apps/commerce-api/src/main/java/com/loopers/domain/brand/BrandService.java

@@ -0,0 +1,30 @@
+package com.loopers.domain.brand;
+
+import com.loopers.support.error.CoreException;
+import com.loopers.support.error.ErrorMessage;
+import com.loopers.support.error.ErrorType;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+
+@Service
+@RequiredArgsConstructor
+public class BrandService {
+
+    private final BrandRepository brandRepository;
+
+    public Brand create(String name, String description) {
+        Brand brand = Brand.create(null, name, description);
+        return  brandRepository.create(brand);
+    }
+
+    public Brand update(Long id, String name, String description) {
+        Brand brand = getById(id);
+        brand.update(name, description);
+        return brandRepository.update(brand);
+    }
+
+    public Brand getById(Long id) {
+        return brandRepository.findById(id)
+            .orElseThrow(() -> new CoreException(ErrorType.BAD_REQUEST, ErrorMessage.Brand.BRAND_NOT_FOUND));
+    }
+}

apps/commerce-api/src/main/java/com/loopers/domain/common/Money.java

@@ -0,0 +1,27 @@
+package com.loopers.domain.common;
+
+import com.loopers.support.error.CoreException;
+import com.loopers.support.error.ErrorMessage;
+import com.loopers.support.error.ErrorType;
+
+/**
+ * 금액 Value Object
+ */
+public record Money(Integer value) {
+
+    public static final Money ZERO = new Money(0);
+
+    public Money {
+        if (value == null || value < 0) {
+            throw new CoreException(ErrorType.BAD_REQUEST, ErrorMessage.Money.AMOUNT_INVALID);
+        }
+    }
+
+    public Money add(Money other) {
+        return new Money(this.value + other.value);
+    }
+
+    public Money multiply(int multiplier) {
+        return new Money(this.value * multiplier);
+    }
+}