task solved

src/main/java/mate/academy/StartClass.java

@@ -1,59 +1,53 @@
 package mate.academy;
 
+import java.math.BigDecimal;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
 import mate.academy.dao.BookDao;
 import mate.academy.dao.BookDaoImpl;
 import mate.academy.model.Book;
 import mate.academy.service.BookService;
 import mate.academy.service.BookServiceImpl;
 
-import java.math.BigDecimal;
-import java.util.ArrayList;
-import java.util.List;
-import java.util.Optional;
-import java.util.stream.Collectors;
-
 public class StartClass {
-    private final static BookDao bookDao = new BookDaoImpl();
-    private final static BookService bookService = new BookServiceImpl(bookDao);
-    private final static int AMOUNT_OF_BOOKS = 5;
-    private final static Long FIRST_BOOK_ID = 1L;
-    private final static Long SECOND_BOOK_ID = 2L;
-    private final static Long THIRD_BOOK_ID = 3L;
-    private final static Long FOURTH_BOOK_ID = 4L;
-    private final static Long FIFTH_BOOK_ID = 5L;
-
-
     public static void main(String[] args) {
+        final Long secondBookId = 2L;
+        final Long thirdBookId = 3L;
+
+        final BookDao bookDao = new BookDaoImpl();
+        final BookService bookService = new BookServiceImpl(bookDao);
         List<Book> books = createBook();
-        Book newBook = new Book("okok", BigDecimal.valueOf(420));
+        Book newBook = new Book(3L,"okok", BigDecimal.valueOf(420));
 
         bookService.create(books.get(0));//C
         bookService.create(books.get(1));
         bookService.create(books.get(2));
         bookService.create(books.get(3));
         bookService.create(books.get(4));
 
-        Optional<Book> book = bookService.readID(SECOND_BOOK_ID);//R
+        Optional<Book> book = bookService.readID(secondBookId);//R
 
-        boolean delete = bookService.delete(THIRD_BOOK_ID);//D
+        boolean delete = bookService.delete(thirdBookId);//D
 
         Book update = bookService.update(newBook);//U
 
         List<Book> listOfBooks = bookService.readAll();
 
-        System.out.println("We have " + book +
-                ", we delete third book? -> " + delete +
-                " and we updated this book -> " + update);
+        System.out.println("We have " + book
+                + ", we delete third book? -> " + delete
+                + " and we updated this book -> " + update);
         for (int i = 0; i < listOfBooks.size(); i++) {
             System.out.println("Our " + i + "th book: " + listOfBooks.get(i));
         }
     }
 
     private static List<Book> createBook() {
+        final int amountOfBooks = 5;
         String title = "Java";
         BigDecimal price = BigDecimal.valueOf(12.32);
         List<Book> books = new ArrayList<>();
-        for (int i = 0; i < AMOUNT_OF_BOOKS; i++) {
+        for (int i = 0; i < amountOfBooks; i++) {
             books.add(new Book(title + i,
                     price.add(BigDecimal.valueOf(i))));
         }

src/main/java/mate/academy/dao/BookDao.java

@@ -1,14 +1,17 @@
 package mate.academy.dao;
 
-import mate.academy.model.Book;
 import java.util.List;
 import java.util.Optional;
+import mate.academy.model.Book;
 
 public interface BookDao {
-    void createTable();
-    Book save(Book book);
+    Book create(Book book);
+
     Optional<Book> findById(Long id);
+
     List<Book> findAll();
+
     Book update(Book book);
+
     boolean deleteById(Long id);
 }

src/main/java/mate/academy/dao/BookDaoImpl.java

@@ -1,17 +1,21 @@
 package mate.academy.dao;
 
-import mate.academy.lib.Dao;
-import mate.academy.model.Book;
-
 import java.io.IOException;
 import java.math.BigDecimal;
 import java.nio.file.Files;
 import java.nio.file.Path;
-import java.sql.*;
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.sql.Statement;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Optional;
 import java.util.stream.Collectors;
+import mate.academy.lib.Dao;
+import mate.academy.model.Book;
+import mate.academy.model.DataProcessingException;
 
 @Dao
 public class BookDaoImpl implements BookDao {
@@ -22,13 +26,12 @@ public class BookDaoImpl implements BookDao {
     private static final String PRICE = "price";
     private static final String ADD_LINE = " ";
     private static final String INIT_DB_SQL = "src/main/resources/init_db.sql";
-    private static final String TAKE_BOOK_FROM_DB = "SELECT * FROM book WHERE id = ?";
-    private static final String DELETE_BOOK_FROM_DB = "DELETE * FROM book WHERE id = ?";
-    private static final String TAKE_BOOKS_FROM_DB = "SELECT * FROM book";
-    private static final String SAVE_BOOK_IN_DB = "INSERT INTO book (title, price) VALUES (?, ?)";
+    private static final String TAKE_BOOK_FROM_DB = "SELECT * FROM books WHERE id = ?";
+    private static final String DELETE_BOOK_FROM_DB = "DELETE FROM books WHERE id = ?";
+    private static final String TAKE_BOOKS_FROM_DB = "SELECT * FROM books";
+    private static final String SAVE_BOOK_IN_DB = "INSERT INTO books (title, price) VALUES (?, ?)";
 
-    @Override
-    public void createTable() {
+    public BookDaoImpl() {
         try (Connection connection = ConnectionUtil.getConnection()) {
             String sqlCodeForTable = Files.readAllLines(Path.of(INIT_DB_SQL))
                     .stream()
@@ -37,23 +40,23 @@ public void createTable() {
             PreparedStatement statement = connection.prepareStatement(sqlCodeForTable);
             statement.executeUpdate();
         } catch (SQLException | IOException e) {
-            throw new RuntimeException(e);
+            throw new DataProcessingException(e);
         }
     }
 
     @Override
-    public Book save(Book book) {
+    public Book create(Book book) {
         try (Connection connection = ConnectionUtil.getConnection();
-             PreparedStatement statement = connection.prepareStatement(SAVE_BOOK_IN_DB,
-                     Statement.RETURN_GENERATED_KEYS)) {
+                PreparedStatement statement = connection.prepareStatement(SAVE_BOOK_IN_DB,
+                            Statement.RETURN_GENERATED_KEYS)) {
 
             statement.setString(FIRST_QUESTION_MARK_INDEX,
                     book.getTitle());
             statement.setBigDecimal(SECOND_QUESTION_MARK_INDEX,
                     book.getPrice());
             int end = statement.executeUpdate();
             if (end < 1) {
-                throw new RuntimeException("Failed to save book");
+                throw new DataProcessingException("Failed to save book");
             }
             ResultSet generatedKeys = statement.getGeneratedKeys();
             if (generatedKeys.next()) {
@@ -62,15 +65,15 @@ public Book save(Book book) {
             }
 
         } catch (SQLException e) {
-            throw new RuntimeException(e);
+            throw new DataProcessingException(e);
         }
         return book;
     }
 
     @Override
     public Optional<Book> findById(Long id) {
         try (Connection connection = ConnectionUtil.getConnection();
-             PreparedStatement statement = connection.prepareStatement(TAKE_BOOK_FROM_DB)) {
+                PreparedStatement statement = connection.prepareStatement(TAKE_BOOK_FROM_DB)) {
 
             statement.setLong(FIRST_QUESTION_MARK_INDEX, id);
             ResultSet resultSet = statement.executeQuery();
@@ -87,15 +90,15 @@ public Optional<Book> findById(Long id) {
                 return Optional.of(book);
             }
         } catch (SQLException e) {
-            throw new RuntimeException(e);
+            throw new DataProcessingException(e);
         }
-        return null;
+        return Optional.empty();
     }
 
     @Override
     public List<Book> findAll() {
         try (Connection connection = ConnectionUtil.getConnection();
-             PreparedStatement statement = connection.prepareStatement(TAKE_BOOKS_FROM_DB)) {
+                PreparedStatement statement = connection.prepareStatement(TAKE_BOOKS_FROM_DB)) {
             ResultSet resultSet = statement.executeQuery();
             List<Book> books = new ArrayList<>();
             while (resultSet.next()) {
@@ -111,33 +114,32 @@ public List<Book> findAll() {
             }
             return books;
         } catch (SQLException e) {
-            throw new RuntimeException(e);
+            throw new DataProcessingException(e);
         }
     }
 
     @Override
     public boolean deleteById(Long id) {
         try (Connection connection = ConnectionUtil.getConnection();
-             PreparedStatement statement = connection.prepareStatement(DELETE_BOOK_FROM_DB)) {
+                PreparedStatement statement = connection.prepareStatement(DELETE_BOOK_FROM_DB)) {
 
             statement.setLong(FIRST_QUESTION_MARK_INDEX, id);
-            ResultSet resultSet = statement.executeQuery();
-
-            if (resultSet.next()) {
-                return true;
-            }
+            statement.executeUpdate();
+            return true;
         } catch (SQLException e) {
-            throw new RuntimeException(e);
+            throw new DataProcessingException(e);
         }
-        return false;
     }
 
     @Override
     public Book update(Book book) {
+        if (book.getId() == null) {
+            throw new DataProcessingException();
+        }
         long bookID = book.getId();
         boolean deleteById = deleteById(bookID);
         if (deleteById) {
-            save(book);
+            create(book);
         }
         return book;
     }

src/main/java/mate/academy/dao/ConnectionUtil.java

@@ -3,19 +3,22 @@
 import java.sql.Connection;
 import java.sql.DriverManager;
 import java.sql.SQLException;
+import mate.academy.model.DataProcessingException;
 
 public class ConnectionUtil {
     private static final String DB_URL = "jdbc:mysql://localhost:3306/test";
     private static final String DB_USER = "root";
     private static final String DB_PASSWORD = "root";
     private static final String CLASS_NAME = "com.mysql.cj.jdbc.Driver";
+
     static {
         try {
             Class.forName(CLASS_NAME);
         } catch (ClassNotFoundException e) {
-            throw new RuntimeException(e);
+            throw new DataProcessingException(e);
         }
     }
+
     public static Connection getConnection() throws SQLException {
         return DriverManager.getConnection(DB_URL,DB_USER,DB_PASSWORD);
     }

src/main/java/mate/academy/model/Book.java

@@ -50,10 +50,10 @@ public Book setPrice(BigDecimal price) {
 
     @Override
     public String toString() {
-        return "Book{" +
-                "id=" + id +
-                ", title='" + title + '\'' +
-                ", price=" + price +
-                '}';
+        return "Book{"
+                + "id=" + id
+                + ", title='" + title + '\''
+                + ", price=" + price
+                + '}';
     }
 }

src/main/java/mate/academy/model/DataProcessingException.java

@@ -0,0 +1,18 @@
+package mate.academy.model;
+
+public class DataProcessingException extends RuntimeException {
+    public DataProcessingException() {
+    }
+
+    public DataProcessingException(String message) {
+        super(message);
+    }
+
+    public DataProcessingException(String message, Throwable cause) {
+        super(message, cause);
+    }
+
+    public DataProcessingException(Throwable cause) {
+        super(cause);
+    }
+}

src/main/java/mate/academy/service/BookService.java

@@ -1,13 +1,17 @@
 package mate.academy.service;
 
-import mate.academy.model.Book;
 import java.util.List;
 import java.util.Optional;
+import mate.academy.model.Book;
 
 public interface BookService {
     Book create(Book book);
+
     Optional<Book> readID(Long id);
+
     List<Book> readAll();
+
     Book update(Book book);
+
     boolean delete(Long id);
 }

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

@@ -1,23 +1,20 @@
 package mate.academy.service;
 
-import mate.academy.dao.BookDao;
-import mate.academy.model.Book;
-
 import java.util.List;
 import java.util.Optional;
+import mate.academy.dao.BookDao;
+import mate.academy.model.Book;
 
-public class BookServiceImpl implements BookService{
+public class BookServiceImpl implements BookService {
     private BookDao bookDao;
 
     public BookServiceImpl(BookDao bookDao) {
         this.bookDao = bookDao;
-        bookDao.createTable();
     }
 
-
     @Override
     public Book create(Book book) {
-        return bookDao.save(book);
+        return bookDao.create(book);
     }
 
     @Override

src/main/resources/init_db.sql

@@ -1,4 +1,4 @@
-CREATE TABLE  books (
+CREATE TABLE IF NOT EXISTS books (
     id INT NOT NULL AUTO_INCREMENT,
     title VARCHAR(255),
     price INT,