added category implementation

src/main/java/com/bookstore/controller/BookController.java

@@ -46,30 +46,31 @@ public BookDto getBookById(@PathVariable Long id) {
     @GetMapping("/search")
     @PreAuthorize("hasRole('USER')")
     @Operation(summary = "Search books", description = "Search book by specific search parameters")
-    public List<BookDto> searchBooks(BookSearchParametersDto searchParameters, Pageable pageable) {
-        return bookService.searchBooks(searchParameters, pageable);
+    public List<BookDto> searchBooks(BookSearchParametersDto searchParameters) {
+        return bookService.searchBooks(searchParameters);
     }
 
     @PostMapping
     @ResponseStatus(HttpStatus.CREATED)
     @PreAuthorize("hasRole('ADMIN')")
-    @Operation(summary = "Create a new book", description = "Create a new book")
+    @Operation(summary = "Create a new book(only for admins)", description = "Create a new book")
     public BookDto createBook(@RequestBody @Valid CreateBookRequestDto bookRequestDto) {
         return bookService.createBook(bookRequestDto);
     }
 
     @PutMapping("/{id}")
     @ResponseStatus(HttpStatus.ACCEPTED)
     @PreAuthorize("hasRole('ADMIN')")
-    @Operation(summary = "Update the existing book", description = "Update the existing book")
+    @Operation(summary = "Update the existing book(only for admins)",
+            description = "Update the existing book")
     public void updateBook(@PathVariable Long id,
                            @RequestBody @Valid CreateBookRequestDto bookRequestDto) {
         bookService.updateBook(id, bookRequestDto);
     }
 
     @DeleteMapping("/{id}")
     @PreAuthorize("hasRole('ADMIN')")
-    @Operation(summary = "Delete book", description = "Delete book by specific id")
+    @Operation(summary = "Delete book(only for admins)", description = "Delete book by specific id")
     public void deleteBookById(@PathVariable Long id) {
         bookService.deleteBookById(id);
     }

src/main/java/com/bookstore/controller/CategoryController.java

@@ -0,0 +1,79 @@
+package com.bookstore.controller;
+
+import com.bookstore.dto.book.BookDtoWithoutCategoryIds;
+import com.bookstore.dto.category.CategoryDto;
+import com.bookstore.service.BookService;
+import com.bookstore.service.CategoryService;
+import io.swagger.v3.oas.annotations.Operation;
+import io.swagger.v3.oas.annotations.tags.Tag;
+import java.util.List;
+import lombok.RequiredArgsConstructor;
+import org.springframework.data.domain.Pageable;
+import org.springframework.http.HttpStatus;
+import org.springframework.security.access.prepost.PreAuthorize;
+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 = "Category management", description = "Endpoints for managing categories")
+@RequiredArgsConstructor
+@RestController
+@RequestMapping(value = "/api/categories")
+public class CategoryController {
+    private final CategoryService categoryService;
+    private final BookService bookService;
+
+    @PostMapping
+    @ResponseStatus(HttpStatus.CREATED)
+    @PreAuthorize("hasRole('ADMIN')")
+    @Operation(summary = "Create a new category(only for admins)",
+            description = "Create a new category")
+    public CategoryDto createCategory(@RequestBody CategoryDto categoryDto) {
+        return categoryService.save(categoryDto);
+    }
+
+    @GetMapping
+    @PreAuthorize("hasRole('USER')")
+    @Operation(summary = "Get all categories", description = "Get all categories")
+    public List<CategoryDto> getAll(Pageable pageable) {
+        return categoryService.findAll(pageable);
+    }
+
+    @GetMapping("/{id}")
+    @PreAuthorize("hasRole('USER')")
+    @Operation(summary = "Get category by specific id", description = "Get category by specific id")
+    public CategoryDto getCategoryById(@PathVariable Long id) {
+        return categoryService.getById(id);
+    }
+
+    @PutMapping("/{id}")
+    @ResponseStatus(HttpStatus.ACCEPTED)
+    @PreAuthorize("hasRole('ADMIN')")
+    @Operation(summary = "Update category(only for admins)", description = "Update category")
+    public CategoryDto updateCategory(@PathVariable Long id,
+                                      @RequestBody CategoryDto categoryDto) {
+        return categoryService.update(id, categoryDto);
+    }
+
+    @DeleteMapping("/{id}")
+    @PreAuthorize("hasRole('ADMIN')")
+    @Operation(summary = "Delete book(only for admins)", description = "Delete book")
+    public void deleteCategory(@PathVariable Long id) {
+        categoryService.deleteById(id);
+    }
+
+    @GetMapping("/{id}/books")
+    @PreAuthorize("hasRole('USER')")
+    @Operation(summary = "Get books by specific category_id",
+            description = "Get books by specific category_id")
+    public List<BookDtoWithoutCategoryIds> getBooksByCategoryId(@PathVariable Long id,
+                                                                Pageable pageable) {
+        return bookService.findAllByCategoryId(id, pageable);
+    }
+}

src/main/java/com/bookstore/dto/book/BookDto.java

@@ -1,6 +1,7 @@
 package com.bookstore.dto.book;
 
 import java.math.BigDecimal;
+import java.util.Set;
 import lombok.Data;
 
 @Data
@@ -12,4 +13,5 @@ public class BookDto {
     private BigDecimal price;
     private String description;
     private String coverImage;
+    private Set<Long> categoryIds;
 }

src/main/java/com/bookstore/dto/book/BookDtoWithoutCategoryIds.java

@@ -0,0 +1,15 @@
+package com.bookstore.dto.book;
+
+import java.math.BigDecimal;
+import lombok.Data;
+
+@Data
+public class BookDtoWithoutCategoryIds {
+    private Long id;
+    private String title;
+    private String author;
+    private String isbn;
+    private BigDecimal price;
+    private String description;
+    private String coverImage;
+}

src/main/java/com/bookstore/dto/book/CreateBookRequestDto.java

@@ -4,6 +4,7 @@
 import jakarta.validation.constraints.Min;
 import jakarta.validation.constraints.NotNull;
 import java.math.BigDecimal;
+import java.util.Set;
 import lombok.Data;
 
 @Data
@@ -19,4 +20,6 @@ public class CreateBookRequestDto {
     private BigDecimal price;
     private String description;
     private String coverImage;
+    @NotNull
+    private Set<Long> categoryIds;
 }

src/main/java/com/bookstore/dto/category/CategoryDto.java

@@ -0,0 +1,9 @@
+package com.bookstore.dto.category;
+
+import lombok.Data;
+
+@Data
+public class CategoryDto {
+    private String name;
+    private String description;
+}

src/main/java/com/bookstore/mapper/BookMapper.java

@@ -2,13 +2,41 @@
 
 import com.bookstore.config.MapperConfig;
 import com.bookstore.dto.book.BookDto;
+import com.bookstore.dto.book.BookDtoWithoutCategoryIds;
 import com.bookstore.dto.book.CreateBookRequestDto;
 import com.bookstore.model.Book;
+import com.bookstore.model.Category;
+import java.util.Set;
+import java.util.stream.Collectors;
+import org.mapstruct.AfterMapping;
 import org.mapstruct.Mapper;
+import org.mapstruct.MappingTarget;
+import org.mapstruct.Named;
 
 @Mapper(config = MapperConfig.class)
 public interface BookMapper {
     BookDto toDto(Book book);
 
     Book toBookModel(CreateBookRequestDto bookRequestDto);
+
+    BookDtoWithoutCategoryIds toDtoWithoutCategories(Book book);
+
+    @AfterMapping
+    default void setCategoryIds(@MappingTarget BookDto bookDto, Book book) {
+        Set<Long> ids = book.getCategories()
+                .stream()
+                .map(Category::getId)
+                .collect(Collectors.toSet());
+        bookDto.setCategoryIds(ids);
+    }
+
+    @Named("bookFromId")
+    default Book bookFromId(Long id) {
+        if (id == null) {
+            throw new RuntimeException("Id can't be null.");
+        }
+        Book book = new Book();
+        book.setId(id);
+        return book;
+    }
 }

src/main/java/com/bookstore/mapper/CategoryMapper.java

@@ -0,0 +1,13 @@
+package com.bookstore.mapper;
+
+import com.bookstore.config.MapperConfig;
+import com.bookstore.dto.category.CategoryDto;
+import com.bookstore.model.Category;
+import org.mapstruct.Mapper;
+
+@Mapper(config = MapperConfig.class)
+public interface CategoryMapper {
+    CategoryDto toDto(Category category);
+
+    Category toEntity(CategoryDto categoryDto);
+}

src/main/java/com/bookstore/model/Book.java

@@ -5,8 +5,13 @@
 import jakarta.persistence.GeneratedValue;
 import jakarta.persistence.GenerationType;
 import jakarta.persistence.Id;
+import jakarta.persistence.JoinColumn;
+import jakarta.persistence.JoinTable;
+import jakarta.persistence.ManyToMany;
 import jakarta.persistence.Table;
 import java.math.BigDecimal;
+import java.util.HashSet;
+import java.util.Set;
 import lombok.Getter;
 import lombok.Setter;
 import org.hibernate.annotations.SQLDelete;
@@ -36,5 +41,11 @@ public class Book {
     private String coverImage;
     @Column(name = "is_deleted",
             nullable = false)
+    @ManyToMany
+    @JoinTable(name = "books_categories",
+            joinColumns = @JoinColumn(name = "book_id"),
+            inverseJoinColumns = @JoinColumn(name = "category_id"))
+    private Set<Category> categories = new HashSet<>();
+    @Column(name = "is_deleted", nullable = false)
     private boolean isDeleted = false;
 }

src/main/java/com/bookstore/model/Category.java

@@ -0,0 +1,31 @@
+package com.bookstore.model;
+
+import jakarta.persistence.Column;
+import jakarta.persistence.Entity;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import jakarta.persistence.Table;
+import lombok.EqualsAndHashCode;
+import lombok.Getter;
+import lombok.Setter;
+import org.hibernate.annotations.SQLDelete;
+import org.hibernate.annotations.Where;
+
+@Getter
+@Setter
+@EqualsAndHashCode
+@Entity
+@SQLDelete(sql = "UPDATE categories SET is_deleted=true WHERE id=?")
+@Where(clause = "is_deleted=false")
+@Table(name = "categories")
+public class Category {
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+    @Column(nullable = false)
+    private String name;
+    private String description;
+    @Column(name = "is_deleted", nullable = false)
+    private boolean isDeleted = false;
+}

src/main/java/com/bookstore/repository/book/BookRepository.java

@@ -1,9 +1,27 @@
 package com.bookstore.repository.book;
 
 import com.bookstore.model.Book;
+import java.util.List;
+import java.util.Optional;
+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;
 
 public interface BookRepository extends JpaRepository<Book, Long>,
         JpaSpecificationExecutor<Book> {
+    @Query("FROM Book b JOIN FETCH b.categories c "
+            + "WHERE c.id = :categoryId")
+    List<Book> findAllByCategoryId(Long categoryId, Pageable pageable);
+
+    @EntityGraph(attributePaths = "categories")
+    Optional<Book> findById(Long id);
+
+    @Query("FROM Book b LEFT JOIN FETCH b.categories c")
+    List<Book> findAllPageable(Pageable pageable);
+
+    @EntityGraph(attributePaths = "categories")
+    List<Book> findAll(Specification<Book> bookSpecification);
 }

src/main/java/com/bookstore/repository/category/CategoryRepository.java

@@ -0,0 +1,9 @@
+package com.bookstore.repository.category;
+
+import com.bookstore.model.Category;
+import java.util.Set;
+import org.springframework.data.jpa.repository.JpaRepository;
+
+public interface CategoryRepository extends JpaRepository<Category, Long> {
+    Set<Category> findByIdIn(Set<Long> categoryIds);
+}

src/main/java/com/bookstore/service/BookService.java

@@ -1,6 +1,7 @@
 package com.bookstore.service;
 
 import com.bookstore.dto.book.BookDto;
+import com.bookstore.dto.book.BookDtoWithoutCategoryIds;
 import com.bookstore.dto.book.BookSearchParametersDto;
 import com.bookstore.dto.book.CreateBookRequestDto;
 import java.util.List;
@@ -17,5 +18,7 @@ public interface BookService {
 
     void deleteBookById(Long id);
 
-    List<BookDto> searchBooks(BookSearchParametersDto searchParameters, Pageable pageable);
+    List<BookDto> searchBooks(BookSearchParametersDto searchParameters);
+
+    List<BookDtoWithoutCategoryIds> findAllByCategoryId(Long categoryId, Pageable pageable);
 }

src/main/java/com/bookstore/service/CategoryService.java

@@ -0,0 +1,17 @@
+package com.bookstore.service;
+
+import com.bookstore.dto.category.CategoryDto;
+import java.util.List;
+import org.springframework.data.domain.Pageable;
+
+public interface CategoryService {
+    List<CategoryDto> findAll(Pageable pageable);
+
+    CategoryDto getById(Long id);
+
+    CategoryDto save(CategoryDto categoryDto);
+
+    CategoryDto update(Long id, CategoryDto categoryDto);
+
+    void deleteById(Long id);
+}