Implement Shopping Cart Management with entities ShoppingCart and Car…

…tItem... (#13)

* Implement Shopping Cart Management with entities ShoppingCart and CartItem, endpoints for adding, updating, viewing, and deleting cart items, security configurations, Liquibase integration, pagination, sorting, and BookMapper.

* Implemented QuantityRequestDto and refactored related code

* CartItemService methods merged into ShoppingCartService to prevent code duplication and improve convenience. Fixed LazyInitializationException occurrences.

src/main/java/mate/academy/bookstore/controller/ShoppingCartController.java

@@ -0,0 +1,70 @@
+package mate.academy.bookstore.controller;
+
+import io.swagger.v3.oas.annotations.Operation;
+import io.swagger.v3.oas.annotations.tags.Tag;
+import jakarta.validation.Valid;
+import lombok.RequiredArgsConstructor;
+import mate.academy.bookstore.dto.cart.CartItemRequestDto;
+import mate.academy.bookstore.dto.cart.CartItemResponseDto;
+import mate.academy.bookstore.dto.cart.QuantityRequestDto;
+import mate.academy.bookstore.dto.cart.ShoppingCartDto;
+import mate.academy.bookstore.model.User;
+import mate.academy.bookstore.service.ShoppingCartService;
+import org.springframework.http.HttpStatus;
+import org.springframework.security.access.prepost.PreAuthorize;
+import org.springframework.security.core.annotation.AuthenticationPrincipal;
+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.PostMapping;
+import org.springframework.web.bind.annotation.PutMapping;
+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;
+
+@Tag(name = "Shopping Cart Management", description = "Endpoints for managing the shopping cart")
+@RestController
+@RequestMapping("/cart")
+@RequiredArgsConstructor
+public class ShoppingCartController {
+    private final ShoppingCartService shoppingCartService;
+
+    @GetMapping
+    @PreAuthorize("hasAnyRole('USER', 'ADMIN')")
+    @ResponseStatus(HttpStatus.OK)
+    @Operation(summary = "Retrieve the shopping cart",
+            description = "Fetch the current shopping cart for the authenticated user")
+    public ShoppingCartDto getShoppingCart(@AuthenticationPrincipal User user) {
+        return shoppingCartService.getByUser(user);
+    }
+
+    @PostMapping
+    @PreAuthorize("hasAnyRole('USER', 'ADMIN')")
+    @ResponseStatus(HttpStatus.CREATED)
+    @Operation(summary = "Add a new item to the shopping cart",
+            description = "Add a new item to the user's shopping cart")
+    public CartItemResponseDto addCartItem(@RequestBody @Valid CartItemRequestDto requestDto,
+                                           @AuthenticationPrincipal User user) {
+        return shoppingCartService.addCartItem(user, requestDto);
+    }
+
+    @PutMapping("/cart-items/{cartItemId}")
+    @PreAuthorize("hasAnyRole('USER', 'ADMIN')")
+    @ResponseStatus(HttpStatus.ACCEPTED)
+    @Operation(summary = "Modify the quantity of an item in the cart",
+            description = "Update the quantity of a specified item in the user's shopping cart")
+    public CartItemResponseDto updateCartItem(@PathVariable Long cartItemId,
+                                              @RequestBody QuantityRequestDto quantity) {
+        return shoppingCartService.updateQuantity(cartItemId, quantity);
+    }
+
+    @DeleteMapping("/cart-items/{cartItemId}")
+    @PreAuthorize("hasAnyRole('USER', 'ADMIN')")
+    @ResponseStatus(HttpStatus.NO_CONTENT)
+    @Operation(summary = "Remove an item from the shopping cart",
+            description = "Delete a specified item from the user's shopping cart, if it exists")
+    public void deleteCartItem(@PathVariable Long cartItemId) {
+        shoppingCartService.deleteCartItem(cartItemId);
+    }
+}

src/main/java/mate/academy/bookstore/dto/cart/CartItemRequestDto.java

@@ -0,0 +1,13 @@
+package mate.academy.bookstore.dto.cart;
+
+import jakarta.validation.constraints.Min;
+import jakarta.validation.constraints.NotNull;
+import lombok.Data;
+
+@Data
+public class CartItemRequestDto {
+    @NotNull
+    private Long bookId;
+    @Min(1)
+    private int quantity;
+}

src/main/java/mate/academy/bookstore/dto/cart/CartItemResponseDto.java

@@ -0,0 +1,11 @@
+package mate.academy.bookstore.dto.cart;
+
+import lombok.Data;
+
+@Data
+public class CartItemResponseDto {
+    private Long id;
+    private Long bookId;
+    private String bookTitle;
+    private int quantity;
+}

src/main/java/mate/academy/bookstore/dto/cart/QuantityRequestDto.java

@@ -0,0 +1,12 @@
+package mate.academy.bookstore.dto.cart;
+
+import jakarta.validation.constraints.Min;
+import jakarta.validation.constraints.NotNull;
+import lombok.Data;
+
+@Data
+public class QuantityRequestDto {
+    @NotNull
+    @Min(1)
+    private int quantity;
+}

src/main/java/mate/academy/bookstore/dto/cart/ShoppingCartDto.java

@@ -0,0 +1,11 @@
+package mate.academy.bookstore.dto.cart;
+
+import java.util.Set;
+import lombok.Data;
+
+@Data
+public class ShoppingCartDto {
+    private Long id;
+    private Long userId;
+    private Set<CartItemResponseDto> cartItems;
+}

src/main/java/mate/academy/bookstore/mapper/CartItemMapper.java

@@ -0,0 +1,14 @@
+package mate.academy.bookstore.mapper;
+
+import mate.academy.bookstore.config.MapperConfig;
+import mate.academy.bookstore.dto.cart.CartItemResponseDto;
+import mate.academy.bookstore.model.CartItem;
+import org.mapstruct.Mapper;
+import org.mapstruct.Mapping;
+
+@Mapper(config = MapperConfig.class)
+public interface CartItemMapper {
+    @Mapping(source = "book.id", target = "bookId")
+    @Mapping(source = "book.title", target = "bookTitle")
+    CartItemResponseDto toDto(CartItem cartItem);
+}

src/main/java/mate/academy/bookstore/mapper/ShoppingCartMapper.java

@@ -0,0 +1,13 @@
+package mate.academy.bookstore.mapper;
+
+import mate.academy.bookstore.config.MapperConfig;
+import mate.academy.bookstore.dto.cart.ShoppingCartDto;
+import mate.academy.bookstore.model.ShoppingCart;
+import org.mapstruct.Mapper;
+import org.mapstruct.Mapping;
+
+@Mapper(config = MapperConfig.class, uses = {CartItemMapper.class})
+public interface ShoppingCartMapper {
+    @Mapping(source = "user.id", target = "userId")
+    ShoppingCartDto toDto(ShoppingCart shoppingCart);
+}

src/main/java/mate/academy/bookstore/model/CartItem.java

@@ -0,0 +1,36 @@
+package mate.academy.bookstore.model;
+
+import jakarta.persistence.Column;
+import jakarta.persistence.Entity;
+import jakarta.persistence.FetchType;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import jakarta.persistence.JoinColumn;
+import jakarta.persistence.ManyToOne;
+import jakarta.persistence.Table;
+import lombok.EqualsAndHashCode;
+import lombok.Getter;
+import lombok.Setter;
+
+@Getter
+@Setter
+@EqualsAndHashCode(of = {"id", "shoppingCart", "book"})
+@Entity
+@Table(name = "cart_items")
+public class CartItem {
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    @JoinColumn(name = "shopping_cart_id", nullable = false)
+    private ShoppingCart shoppingCart;
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    @JoinColumn(name = "book_id", nullable = false)
+    private Book book;
+
+    @Column(nullable = false)
+    private int quantity;
+}

src/main/java/mate/academy/bookstore/model/ShoppingCart.java

@@ -0,0 +1,41 @@
+package mate.academy.bookstore.model;
+
+import jakarta.persistence.CascadeType;
+import jakarta.persistence.Entity;
+import jakarta.persistence.FetchType;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import jakarta.persistence.JoinColumn;
+import jakarta.persistence.OneToMany;
+import jakarta.persistence.OneToOne;
+import jakarta.persistence.Table;
+import java.util.HashSet;
+import java.util.Set;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+import org.hibernate.annotations.SoftDelete;
+
+@Getter
+@Setter
+@Entity
+@SoftDelete
+@NoArgsConstructor
+@Table(name = "shopping_carts")
+public class ShoppingCart {
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @OneToOne(fetch = FetchType.LAZY)
+    @JoinColumn(name = "user_id", referencedColumnName = "id", nullable = false)
+    private User user;
+
+    @OneToMany(mappedBy = "shoppingCart", cascade = CascadeType.REMOVE)
+    private Set<CartItem> cartItems = new HashSet<>();
+
+    public ShoppingCart(User user) {
+        this.user = user;
+    }
+}

src/main/java/mate/academy/bookstore/repository/book/BookRepository.java

@@ -2,14 +2,23 @@
 
 import java.util.List;
 import mate.academy.bookstore.model.Book;
+import org.springframework.data.domain.Page;
 import org.springframework.data.domain.Pageable;
+import org.springframework.data.jpa.domain.Specification;
 import org.springframework.data.jpa.repository.EntityGraph;
 import org.springframework.data.jpa.repository.JpaRepository;
 import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
 import org.springframework.data.jpa.repository.Query;
 import org.springframework.data.repository.query.Param;
 
 public interface BookRepository extends JpaRepository<Book, Long>, JpaSpecificationExecutor<Book> {
+
+    @Query("FROM Book b JOIN FETCH b.categories")
+    List<Book> findAllBooks(Pageable pageable);
+
+    @EntityGraph(attributePaths = {"categories"})
+    Page<Book> findAll(Specification<Book> specification, Pageable pageable);
+
     @EntityGraph(attributePaths = {"categories"})
     Book findBookByIsbn(String isbn);
 

src/main/java/mate/academy/bookstore/repository/cart/CartItemRepository.java

@@ -0,0 +1,12 @@
+package mate.academy.bookstore.repository.cart;
+
+import java.util.Optional;
+import mate.academy.bookstore.model.Book;
+import mate.academy.bookstore.model.CartItem;
+import mate.academy.bookstore.model.ShoppingCart;
+import org.springframework.data.jpa.repository.JpaRepository;
+
+public interface CartItemRepository extends JpaRepository<CartItem, Long> {
+
+    Optional<CartItem> findByShoppingCartAndBook(ShoppingCart shoppingCart, Book book);
+}

src/main/java/mate/academy/bookstore/repository/cart/ShoppingCartRepository.java

@@ -0,0 +1,13 @@
+package mate.academy.bookstore.repository.cart;
+
+import java.util.Optional;
+import mate.academy.bookstore.model.ShoppingCart;
+import mate.academy.bookstore.model.User;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Query;
+
+public interface ShoppingCartRepository extends JpaRepository<ShoppingCart, Long> {
+
+    @Query("FROM ShoppingCart sc JOIN FETCH sc.cartItems WHERE sc.user = :user")
+    Optional<ShoppingCart> findByUser(User user);
+}

src/main/java/mate/academy/bookstore/repository/user/UserRepository.java

@@ -3,9 +3,11 @@
 import java.util.Optional;
 import mate.academy.bookstore.model.User;
 import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Query;
 
 public interface UserRepository extends JpaRepository<User, Long> {
     boolean existsByEmailIgnoreCase(String email);
 
+    @Query("FROM User u JOIN FETCH u.roles WHERE u.email = :email")
     Optional<User> findByEmail(String email);
 }

src/main/java/mate/academy/bookstore/service/ShoppingCartService.java

@@ -0,0 +1,21 @@
+package mate.academy.bookstore.service;
+
+import mate.academy.bookstore.dto.cart.CartItemRequestDto;
+import mate.academy.bookstore.dto.cart.CartItemResponseDto;
+import mate.academy.bookstore.dto.cart.QuantityRequestDto;
+import mate.academy.bookstore.dto.cart.ShoppingCartDto;
+import mate.academy.bookstore.model.ShoppingCart;
+import mate.academy.bookstore.model.User;
+
+public interface ShoppingCartService {
+
+    ShoppingCart create(User user);
+
+    ShoppingCartDto getByUser(User user);
+
+    CartItemResponseDto addCartItem(User user, CartItemRequestDto requestItemDto);
+
+    CartItemResponseDto updateQuantity(Long itemId, QuantityRequestDto quantity);
+
+    void deleteCartItem(Long cartItemId);
+}

src/main/java/mate/academy/bookstore/service/impl/BookServiceImpl.java

@@ -46,7 +46,7 @@ public BookDto save(CreateBookRequestDto requestDto) {
 
     @Override
     public List<BookDto> findAll(Pageable pageable) {
-        return bookRepository.findAll(pageable).stream()
+        return bookRepository.findAllBooks(pageable).stream()
                 .map(bookMapper::toDto)
                 .toList();
     }