1. Add Data transfer object(DTOs) 2. use builder pattern #52

pom.xml

@@ -37,6 +37,17 @@
 			<artifactId>spring-boot-starter-data-jpa</artifactId>
 		</dependency>
 
+		<dependency>
+			<groupId>org.projectlombok</groupId>
+			<artifactId>lombok</artifactId>
+			<optional>true</optional>
+		</dependency>
+		<dependency>
+			<groupId>org.modelmapper</groupId>
+			<artifactId>modelmapper</artifactId>
+			<version>3.0.0</version>
+		</dependency>
+
 
 		<dependency>
 			<groupId>org.springframework.boot</groupId>

src/main/java/com/libraryman_api/book/Book.java

@@ -1,9 +1,17 @@
 package com.libraryman_api.book;
 
 import jakarta.persistence.*;
+import lombok.*;
+
 
 
 @Entity
+@AllArgsConstructor
+@NoArgsConstructor
+@Getter
+@Setter
+@Builder
+@ToString
 public class Book {
     @Id
 
@@ -33,91 +41,5 @@ public class Book {
     @Column(name = "copies_available", nullable = false)
     private int copiesAvailable;
 
-    public Book() {
-    }
-
-    public Book(String title, String author, String isbn, String publisher, int publishedYear, String genre, int copiesAvailable) {
-        this.title = title;
-        this.author = author;
-        this.isbn = isbn;
-        this.publisher = publisher;
-        this.publishedYear = publishedYear;
-        this.genre = genre;
-        this.copiesAvailable = copiesAvailable;
-    }
-
-    public int getBookId() {
-        return bookId;
-    }
-
-    public String getTitle() {
-        return title;
-    }
-
-    public String getAuthor() {
-        return author;
-    }
-
-    public String getIsbn() {
-        return isbn;
-    }
-
-    public String getPublisher() {
-        return publisher;
-    }
-
-    public int getPublishedYear() {
-        return publishedYear;
-    }
-
-    public String getGenre() {
-        return genre;
-    }
-
-    public int getCopiesAvailable() {
-        return copiesAvailable;
-    }
-
-
-    public void setTitle(String title) {
-        this.title = title;
-    }
-
-    public void setAuthor(String author) {
-        this.author = author;
-    }
-
-    public void setIsbn(String isbn) {
-        this.isbn = isbn;
-    }
-
-    public void setPublisher(String publisher) {
-        this.publisher = publisher;
-    }
-
-    public void setPublishedYear(int publishedYear) {
-        this.publishedYear = publishedYear;
-    }
-
-    public void setGenre(String genre) {
-        this.genre = genre;
-    }
-
-    public void setCopiesAvailable(int copiesAvailable) {
-        this.copiesAvailable = copiesAvailable;
-    }
 
-    @Override
-    public String toString() {
-        return "Books{" +
-                "bookId=" + bookId +
-                ", title='" + title + '\'' +
-                ", author='" + author + '\'' +
-                ", isbn='" + isbn + '\'' +
-                ", publisher='" + publisher + '\'' +
-                ", publishedYear=" + publishedYear +
-                ", genre='" + genre + '\'' +
-                ", copiesAvailable=" + copiesAvailable +
-                '}';
-    }
 }

src/main/java/com/libraryman_api/book/BookController.java

@@ -23,22 +23,23 @@ public class BookController {
     /**
      * Retrieves a list of all books in the library.
      *
-     * @return a list of {@link Book} objects representing all the books in the library.
+     * @return a list of {@link BookDto} objects representing all the books in the library.
      */
     @GetMapping
-    public List<Book> getAllBooks() {
+    public List<BookDto> getAllBooks() {
+
         return bookService.getAllBooks();
     }
 
     /**
      * Retrieves a book by its ID.
      *
      * @param id the ID of the book to retrieve.
-     * @return a {@link ResponseEntity} containing the {@link Book} object, if found.
+     * @return a {@link ResponseEntity} containing the {@link BookDto} object, if found.
      * @throws ResourceNotFoundException if the book with the specified ID is not found.
      */
     @GetMapping("/{id}")
-    public ResponseEntity<Book> getBookById(@PathVariable int id) {
+    public ResponseEntity<BookDto> getBookById(@PathVariable int id) {
         return bookService.getBookById(id)
                 .map(ResponseEntity::ok)
                 .orElseThrow(() -> new ResourceNotFoundException("Book not found"));
@@ -47,24 +48,24 @@ public ResponseEntity<Book> getBookById(@PathVariable int id) {
     /**
      * Adds a new book to the library.
      *
-     * @param book the {@link Book} object representing the new book to add.
+     * @param bookDto the {@link Book} object representing the new book to add.
      * @return the added {@link Book} object.
      */
     @PostMapping
-    public Book addBook(@RequestBody Book book) {
-        return bookService.addBook(book);
+    public BookDto addBook(@RequestBody BookDto bookDto) {
+        return bookService.addBook(bookDto);
     }
 
     /**
      * Updates an existing book in the library.
      *
      * @param id          the ID of the book to update.
-     * @param bookDetails the {@link Book} object containing the updated book details.
+     * @param bookDtoDetails the {@link Book} object containing the updated book details.
      * @return the updated {@link Book} object.
      */
     @PutMapping("/{id}")
-    public Book updateBook(@PathVariable int id, @RequestBody Book bookDetails) {
-        return bookService.updateBook(id, bookDetails);
+    public BookDto updateBook(@PathVariable int id, @RequestBody BookDto bookDtoDetails) {
+        return bookService.updateBook(id, bookDtoDetails);
     }
 
     /**

src/main/java/com/libraryman_api/book/BookDto.java

@@ -0,0 +1,34 @@
+package com.libraryman_api.book;
+
+import jakarta.persistence.Column;
+import lombok.*;
+
+@Getter
+@Setter
+@AllArgsConstructor
+@NoArgsConstructor
+@ToString
+@Builder
+public class BookDto {
+
+
+    private int bookId;
+
+    private String title;
+
+    private String author;
+
+    private String isbn;
+
+    private String publisher;
+
+    private int publishedYear;
+
+    private String genre;
+
+
+    private int copiesAvailable;
+
+
+
+}

src/main/java/com/libraryman_api/book/BookService.java

@@ -1,6 +1,8 @@
 package com.libraryman_api.book;
 
 import com.libraryman_api.exception.ResourceNotFoundException;
+import org.modelmapper.ModelMapper;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Service;
 
 import java.util.List;
@@ -25,13 +27,16 @@
 public class BookService {
 
     private final BookRepository bookRepository;
+    @Autowired
+    private ModelMapper mapper;
 
     /**
      * Constructs a new {@code BookService} with the specified {@code BookRepository}.
      *
      * @param bookRepository the repository to be used by this service to interact with the database
      */
     public BookService(BookRepository bookRepository) {
+
         this.bookRepository = bookRepository;
     }
 
@@ -40,8 +45,9 @@ public BookService(BookRepository bookRepository) {
      *
      * @return a list of all books
      */
-    public List<Book> getAllBooks() {
-        return bookRepository.findAll();
+    public List<BookDto> getAllBooks() {
+        List<Book> allBooks = bookRepository.findAll();
+         return allBooks.stream().map(this::EntityToDto).toList();
     }
 
     /**
@@ -50,39 +56,44 @@ public List<Book> getAllBooks() {
      * @param bookId the ID of the book to retrieve
      * @return an {@code Optional} containing the found book, or {@code Optional.empty()} if no book was found
      */
-    public Optional<Book> getBookById(int bookId) {
-        return bookRepository.findById(bookId);
+    public Optional<BookDto> getBookById(int bookId) {
+
+        Optional<Book> getBook = bookRepository.findById(bookId);
+        return getBook.map(this::EntityToDto);
     }
 
     /**
      * Adds a new book to the database.
      *
-     * @param book the book to be added
+     * @param bookDto the book to be added
      * @return the saved book
      */
-    public Book addBook(Book book) {
-        return bookRepository.save(book);
+    public BookDto addBook(BookDto bookDto) {
+        Book book = DtoToEntity(bookDto);
+        Book savedBook = bookRepository.save(book);
+        return EntityToDto(savedBook);
     }
 
     /**
      * Updates an existing book with the given details.
      *
      * @param bookId the ID of the book to update
-     * @param bookDetails the new details for the book
+     * @param bookDtoDetails the new details for the book
      * @return the updated book
      * @throws ResourceNotFoundException if the book with the specified ID is not found
      */
-    public Book updateBook(int bookId, Book bookDetails) {
+    public BookDto updateBook(int bookId, BookDto bookDtoDetails) {
         Book book = bookRepository.findById(bookId)
                 .orElseThrow(() -> new ResourceNotFoundException("Book not found"));
-        book.setTitle(bookDetails.getTitle());
-        book.setAuthor(bookDetails.getAuthor());
-        book.setIsbn(bookDetails.getIsbn());
-        book.setPublisher(bookDetails.getPublisher());
-        book.setPublishedYear(bookDetails.getPublishedYear());
-        book.setGenre(bookDetails.getGenre());
-        book.setCopiesAvailable(bookDetails.getCopiesAvailable());
-        return bookRepository.save(book);
+        book.setTitle(bookDtoDetails.getTitle());
+        book.setAuthor(bookDtoDetails.getAuthor());
+        book.setIsbn(bookDtoDetails.getIsbn());
+        book.setPublisher(bookDtoDetails.getPublisher());
+        book.setPublishedYear(bookDtoDetails.getPublishedYear());
+        book.setGenre(bookDtoDetails.getGenre());
+        book.setCopiesAvailable(bookDtoDetails.getCopiesAvailable());
+        Book updatedBook = bookRepository.save(book);
+        return EntityToDto(updatedBook);
     }
 
     /**
@@ -97,4 +108,13 @@ public void deleteBook(int bookId) {
         bookRepository.delete(book);
     }
 
+
+
+    public BookDto EntityToDto(Book book){
+        return mapper.map(book,BookDto.class);
+    }
+    public Book DtoToEntity(BookDto bookDto){
+        return mapper.map(bookDto,Book.class);
+    }
+
 }

src/main/java/com/libraryman_api/borrowing/BorrowingController.java

@@ -31,19 +31,20 @@ public BorrowingController(BorrowingService borrowingService) {
      * @return a list of {@link Borrowings} objects representing all borrowings.
      */
     @GetMapping
-    public List<Borrowings> getAllBorrowings() {
+    public List<BorrowingsDto> getAllBorrowings() {
+
         return borrowingService.getAllBorrowings();
     }
 
     /**
      * Records a new book borrowing.
      *
-     * @param borrowing the {@link Borrowings} object containing borrowing details.
+     * @param borrowingDto the {@link Borrowings} object containing borrowing details.
      * @return the saved {@link Borrowings} object representing the borrowing record.
      */
     @PostMapping
-    public Borrowings borrowBook(@RequestBody Borrowings borrowing) {
-        return borrowingService.borrowBook(borrowing);
+    public BorrowingsDto borrowBook(@RequestBody BorrowingsDto borrowingDto) {
+        return borrowingService.borrowBook(borrowingDto);
     }
 
     /**
@@ -52,8 +53,8 @@ public Borrowings borrowBook(@RequestBody Borrowings borrowing) {
      * @param id the ID of the borrowing record to update.
      */
     @PutMapping("/{id}/return")
-    public void returnBook(@PathVariable int id) {
-        borrowingService.returnBook(id);
+    public BorrowingsDto returnBook(@PathVariable int id) {
+        return borrowingService.returnBook(id);
     }
 
     /**
@@ -75,7 +76,7 @@ public String payFine(@PathVariable int id) {
      * @return a list of {@link Borrowings} objects representing the member's borrowings.
      */
     @GetMapping("member/{memberId}")
-    public List<Borrowings> getAllBorrowingsOfAMember(@PathVariable int memberId) {
+    public List<BorrowingsDto> getAllBorrowingsOfAMember(@PathVariable int memberId) {
         return borrowingService.getAllBorrowingsOfMember(memberId);
     }
 
@@ -87,7 +88,7 @@ public List<Borrowings> getAllBorrowingsOfAMember(@PathVariable int memberId) {
      * @throws ResourceNotFoundException if the borrowing record with the specified ID is not found.
      */
     @GetMapping("{borrowingId}")
-    public Borrowings getBorrowingById(@PathVariable int borrowingId) {
+    public BorrowingsDto getBorrowingById(@PathVariable int borrowingId) {
         return borrowingService.getBorrowingById(borrowingId)
                 .orElseThrow(() -> new ResourceNotFoundException("Borrowing not found"));
     }