[6주차] 장바구니 만들기

build.gradle.kts

@@ -16,12 +16,18 @@ repositories {
 }
 
 dependencies {
+    implementation ("org.springframework.boot:spring-boot-starter-data-jpa")
     implementation("org.springframework.boot:spring-boot-starter-web")
     implementation("org.springframework.boot:spring-boot-starter-validation")
 
+    compileOnly ("org.projectlombok:lombok")
+    annotationProcessor ("org.projectlombok:lombok")
+
     developmentOnly("org.springframework.boot:spring-boot-devtools")
 
     testImplementation("org.springframework.boot:spring-boot-starter-test")
+    testCompileOnly ("org.projectlombok:lombok")
+    testAnnotationProcessor ("org.projectlombok:lombok")
 }
 
 tasks.withType<Test> {

src/main/java/com/example/demo/application/CartService.java

@@ -0,0 +1,54 @@
+package com.example.demo.application;
+
+import com.example.demo.model.Cart;
+import com.example.demo.model.LineItemId;
+import com.example.demo.model.Product;
+import com.example.demo.model.ProductId;
+import com.example.demo.model.ProductOption;
+import com.example.demo.repository.CartRepository;
+import com.example.demo.repository.ProductRepository;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+@Service
+@Transactional
+public class CartService {
+
+    private final CartRepository cartRepository;
+    private final ProductRepository productRepository;
+
+    public CartService(CartRepository cartRepository, ProductRepository productRepository) {
+        this.cartRepository = cartRepository;
+        this.productRepository = productRepository;
+    }
+
+    public void addItemToCart(Long cartId, ProductId productId, ProductOption option, int quantity) {
+        Cart cart = cartRepository.findById(cartId)
+                .orElseThrow(() -> new IllegalArgumentException("장바구니가 존재하지 않습니다."));
+        Product product = productRepository.findById(productId)
+                .orElseThrow(() -> new IllegalArgumentException("상품이 존재하지 않습니다."));
+
+        cart.addProduct(productId, option, quantity);
+    }
+
+    public void removeItemFromCart(Long cartId, LineItemId lineItemId) {
+        Cart cart = cartRepository.findById(cartId)
+                .orElseThrow(() -> new IllegalArgumentException("장바구니가 존재하지 않습니다."));
+
+        cart.removeLineItemById(lineItemId);
+    }
+
+    public void clearCart(Long cartId) {
+        Cart cart = cartRepository.findById(cartId)
+                .orElseThrow(() -> new IllegalArgumentException("장바구니가 존재하지 않습니다."));
+
+        cart.clearItems();
+    }
+
+    @Transactional(readOnly = true)
+    public Cart getCart(Long cartId) {
+        return cartRepository.findById(cartId)
+                .orElseThrow(() -> new IllegalArgumentException("장바구니가 존재하지 않습니다."));
+    }
+
+}

src/main/java/com/example/demo/controllers/CartController.java

@@ -1,14 +1,48 @@
 package com.example.demo.controllers;
 
+import com.example.demo.application.CartService;
+import com.example.demo.controllers.dto.CartResponseDto;
+import com.example.demo.controllers.dto.LineItemResponseDto;
+import com.example.demo.model.Cart;
+import lombok.RequiredArgsConstructor;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.DeleteMapping;
 import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RestController;
 
 @RestController
-@RequestMapping("/cart")
+@RequestMapping("/carts")
+@RequiredArgsConstructor
 public class CartController {
-    @GetMapping
-    String detail() {
-        return "";
+
+    private final CartService cartService;
+
+    @GetMapping("/{cartId}")
+    public CartResponseDto getCart(@PathVariable Long cartId) {
+
+        Cart cart = cartService.getCart(cartId);
+
+        return new CartResponseDto(
+                cartId,
+                cart.getTotalQuantity(),
+                cart.getLineItems().stream()
+                        .map(lineItem -> new LineItemResponseDto(
+                                        lineItem.getProductId().id(),
+                                        lineItem.getProductOption().color(),
+                                        lineItem.getProductOption().size(),
+                                        lineItem.getQuantity()
+                                )
+                        ).toList()
+        );
+    }
+
+
+    @DeleteMapping("/{cartId}")
+    public ResponseEntity<Void> deleteCart(@PathVariable Long cartId) {
+        cartService.clearCart(cartId);
+        return new ResponseEntity<>(HttpStatus.NO_CONTENT);
     }
 }

src/main/java/com/example/demo/controllers/LineItemController.java

@@ -1,17 +1,44 @@
 package com.example.demo.controllers;
 
+import com.example.demo.application.CartService;
+import com.example.demo.controllers.dto.LineItemRequestDto;
+import com.example.demo.model.LineItemId;
+import com.example.demo.model.ProductId;
+import com.example.demo.model.ProductOption;
+import lombok.RequiredArgsConstructor;
 import org.springframework.http.HttpStatus;
+import org.springframework.web.bind.annotation.DeleteMapping;
+import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.ResponseStatus;
 import org.springframework.web.bind.annotation.RestController;
 
 @RestController
-@RequestMapping("/cart/line-items")
+@RequestMapping("/carts/{cartId}/line-items")
+@RequiredArgsConstructor
 public class LineItemController {
+
+    private final CartService cartService;
+
     @PostMapping
     @ResponseStatus(HttpStatus.CREATED)
-    void create() {
-        //
+    public void create(@PathVariable Long cartId, @RequestBody LineItemRequestDto requestDto) {
+
+        cartService.addItemToCart(
+                cartId,
+                new ProductId(requestDto.getProductId()),
+                new ProductOption(requestDto.getColor(), requestDto.getSize()),
+                requestDto.getQuantity());
+
     }
+
+    @DeleteMapping("/{lineItemId}")
+    @ResponseStatus(HttpStatus.NO_CONTENT)
+    public void deleteLineItem(@PathVariable Long cartId, @PathVariable String lineItemId) {
+        cartService.removeItemFromCart(
+                cartId, new LineItemId(lineItemId));
+    }
+
 }

src/main/java/com/example/demo/controllers/dto/CartResponseDto.java

@@ -0,0 +1,27 @@
+package com.example.demo.controllers.dto;
+
+import java.util.List;
+
+public class CartResponseDto {
+    private Long cartId;
+    private int totalQuantity;
+    private List<LineItemResponseDto> lineItems;
+
+    public CartResponseDto(Long cartId, int totalQuantity, List<LineItemResponseDto> lineItems) {
+        this.cartId = cartId;
+        this.totalQuantity = totalQuantity;
+        this.lineItems = lineItems;
+    }
+
+    public Long getCartId() {
+        return cartId;
+    }
+
+    public int getTotalQuantity() {
+        return totalQuantity;
+    }
+
+    public List<LineItemResponseDto> getLineItems() {
+        return lineItems;
+    }
+}

src/main/java/com/example/demo/controllers/dto/LineItemRequestDto.java

@@ -0,0 +1,31 @@
+package com.example.demo.controllers.dto;
+
+public class LineItemRequestDto {
+    private String productId;
+    private String color;
+    private String size;
+    private int quantity;
+
+    public LineItemRequestDto(String productId, String color, String size, int quantity) {
+        this.productId = productId;
+        this.color = color;
+        this.size = size;
+        this.quantity = quantity;
+    }
+
+    public String getProductId() {
+        return productId;
+    }
+
+    public String getColor() {
+        return color;
+    }
+
+    public String getSize() {
+        return size;
+    }
+
+    public int getQuantity() {
+        return quantity;
+    }
+}

src/main/java/com/example/demo/controllers/dto/LineItemResponseDto.java

@@ -0,0 +1,32 @@
+package com.example.demo.controllers.dto;
+
+public class LineItemResponseDto {
+
+    private String productId;
+    private String color;
+    private String size;
+    private int quantity;
+
+    public LineItemResponseDto(String productId, String color, String size, int quantity) {
+        this.productId = productId;
+        this.color = color;
+        this.size = size;
+        this.quantity = quantity;
+    }
+
+    public String getProductId() {
+        return productId;
+    }
+
+    public String getColor() {
+        return color;
+    }
+
+    public String getSize() {
+        return size;
+    }
+
+    public int getQuantity() {
+        return quantity;
+    }
+}

src/main/java/com/example/demo/model/Cart.java

@@ -0,0 +1,94 @@
+package com.example.demo.model;
+
+import jakarta.persistence.CascadeType;
+import jakarta.persistence.Entity;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import jakarta.persistence.OneToMany;
+import jakarta.persistence.Table;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+@Entity
+@Table(name="carts")
+public class Cart {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @OneToMany(mappedBy = "cart", cascade = CascadeType.ALL, orphanRemoval = true)
+    private List<LineItem> lineItems = new ArrayList<>();
+
+    private int totalQuantity;
+
+    public Cart() {
+    }
+
+    public Cart(List<LineItem> lineItems) {
+        this.lineItems = new ArrayList<>(lineItems);
+        lineItems.forEach(lineItem -> lineItem.setCart(this));
+        calculateTotalQuantity();
+    }
+
+    public List<LineItem> getLineItems() {
+        return Collections.unmodifiableList(lineItems);
+    }
+
+    public int getTotalQuantity() {
+        return totalQuantity;
+    }
+
+    public void addProduct(ProductId productId, ProductOption productOption, int quantity) {
+
+        LineItem lineItem = findLineItem(productId, productOption);
+
+        if (lineItem != null) {
+            lineItem.addQuantity(quantity, productOption);
+            calculateTotalQuantity();
+            checkValidQuantity();
+            return;
+        }
+
+        lineItem = new LineItem(productId, productOption, quantity);
+        lineItems.add(lineItem);
+        lineItem.setCart(this);
+        calculateTotalQuantity();
+        checkValidQuantity();
+    }
+
+    public void checkValidQuantity() {
+        if (totalQuantity > 20) {
+            throw new IllegalArgumentException("담을수 있는 수량을 초과했습니다.");
+        }
+    }
+
+    private void calculateTotalQuantity() {
+        this.totalQuantity = lineItems.stream()
+                .mapToInt(LineItem::getQuantity)
+                .sum();
+    }
+
+
+    private LineItem findLineItem(ProductId productId, ProductOption productOption) {
+        return lineItems.stream()
+                .filter(lineItem ->
+                        lineItem.isSameProduct(productId,productOption))
+                .findFirst()
+                .orElse(null);
+    }
+
+    public void clearItems() {
+        lineItems.clear();
+        calculateTotalQuantity();
+    }
+
+    public void removeLineItemById(LineItemId lineItemId) {
+        if (lineItemId == null) return;
+        lineItems.removeIf(lineItem ->lineItem.getId().equals(lineItemId));
+        calculateTotalQuantity();
+    }
+}