created UtilConnection;

README.md

@@ -25,7 +25,7 @@ public class Main {
 }
 ```
 **WARNING!!!** Path to your project must contain only english letters. Also, it mustn't contain spaces. In other case `Injector` won't work correctly.
-- Your table should be named `books` and contain these columns: `id`, `title`, `price`.
+- Your table should be named `book` and contain these columns: `id`, `title`, `price`.
 ### Java classes structure:
 - Book
 

checklist.md

@@ -3,7 +3,7 @@
 * Try to avoid code duplication. Especially, when you are working with ResultSet.
   Move retrieving data from ResultSet into Entity object to a separate private method.
 
-* Don't make `books.title` UNIQUE. This is not required in this task.
+* Don't make `book.title` UNIQUE. This is not required in this task.
 
 * When creating a table in MySQL, use `bigint` column type for storing id.
 
@@ -12,11 +12,11 @@
 
 * Use `PreparedStatement` over `Statement`, even for a static query with no parameters in `findAll()` method. It's the best practice, and it's slightly faster.
 
-* Column naming (`books.` is a table name in these examples):
+* Column naming (`book.` is a table name in these examples):
 
-Wrong: `books.bookTitle`, `books.BOOK_TITLE`
+Wrong: `book.bookTitle`, `book.BOOK_TITLE`
 
-Good: `books.title`
+Good: `book.title`
 
 * Use `Statement.RETURN_GENERATED_KEYS` only in `create` statement, it's not needed in other methods.
 
@@ -48,19 +48,19 @@ Good: `books.title`
 
     - Bad practice:
         ```sql  
-        insert into books (..) VALUES (..);    
+        insert into book (..) VALUES (..);    
         ``` 
     - Good practice: 
         ```sql
-        INSERT INTO books (..) VALUES (..);
+        INSERT INTO book (..) VALUES (..);
         ```   
 * Let's save each query in a separate variable.
     - Bad practice:
         ```java
             public List<Book> findAll() {
                 try (Connection connection = ConnectionUtil.getConnection()
                     PreparedStatement preparedStatement = connection
-                        .prepareStatement("SELECT * FROM books")) { // it's bad
+                        .prepareStatement("SELECT * FROM book")) { // it's bad
                     ...
                 } catch (SQLException ex) {
                     ...
@@ -70,7 +70,7 @@ Good: `books.title`
     - Good practice: 
         ```java
             public List<Book> findAll() {
-                String query = "SELECT * FROM books"; // it's good
+                String query = "SELECT * FROM book"; // it's good
                 try (Connection connection = ConnectionUtil.getConnection();
                     PreparedStatement preparedStatement = connection.prepareStatement(query)) {
                     ...
@@ -105,11 +105,11 @@ Good: `books.title`
 
     - Bad practice:
         ```sql  
-        SELECT * FROM schemaname.books WHERE id = 1;                     
+        SELECT * FROM schemaname.book WHERE id = 1;                     
         ``` 
     - Good practice: 
         ```sql
-        SELECT * FROM books WHERE id = 1;
+        SELECT * FROM book WHERE id = 1;
         ```         
 * When you convert `ResultSet` to `Book` better create an object using setters or constructor but not both of them, because it's not consistent to use both ways of initialization of object.
 

pom.xml

@@ -18,6 +18,14 @@
         </maven.checkstyle.plugin.configLocation>
     </properties>
 
+    <dependencies>
+        <dependency>
+            <groupId>mysql</groupId>
+            <artifactId>mysql-connector-java</artifactId>
+            <version>8.0.33</version>
+        </dependency>
+    </dependencies>
+
     <build>
         <plugins>
             <plugin>

src/main/java/mate/academy/Main.java

@@ -1,7 +1,29 @@
 package mate.academy;
 
+import java.math.BigDecimal;
+import java.util.List;
+import mate.academy.dao.BookDao;
+import mate.academy.entity.Book;
+import mate.academy.lib.Injector;
+
 public class Main {
-    public static void main(String[] args) {
+    private static final Injector injector = Injector.getInstance("mate.academy.dao");
 
+    public static void main(String[] args) {
+        BookDao bookDao = (BookDao) injector.getInstance(BookDao.class);
+        List<Book> books = List.of(new Book("First Book", BigDecimal.valueOf(45)),
+                new Book("Second Book", BigDecimal.valueOf(12)),
+                new Book("Third Book", BigDecimal.valueOf(26)));
+        for (Book book : books) {
+            bookDao.create(book);
+        }
+        bookDao.findById(1L);
+        System.out.println(bookDao.findAll());
+        Book book = new Book();
+        book.setId(43L);
+        book.setTitle("Update First Book");
+        book.setPrice(BigDecimal.valueOf(45));
+        bookDao.update(book);
+        bookDao.deleteById(43L);
     }
 }

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

@@ -0,0 +1,17 @@
+package mate.academy.dao;
+
+import java.util.List;
+import java.util.Optional;
+import mate.academy.entity.Book;
+
+public interface BookDao {
+    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

@@ -0,0 +1,118 @@
+package mate.academy.dao;
+
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.sql.Types;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+import mate.academy.entity.Book;
+import mate.academy.exception.DataProcessingException;
+import mate.academy.lib.Dao;
+import mate.academy.util.ConnectionUtil;
+
+@Dao
+public class BookDaoImpl implements BookDao {
+    private static final String CREATE_SQL = "INSERT INTO book (title, price) VALUES (?, ?)";
+    private static final String FIND_BY_ID_SQL = "SELECT * FROM book WHERE id = ?";
+    private static final String FIND_ALL_SQL = "SELECT * FROM book";
+    private static final String UPDATE_BY_ID_SQL = "UPDATE book SET title = ?, "
+            + "price = ? WHERE id = ?";
+    private static final String DELETE_BY_ID_SQL = "DELETE FROM book WHERE id = ?";
+
+    @Override
+    public Book create(Book book) {
+        try (Connection connection = ConnectionUtil.getConnection();
+                PreparedStatement statement = connection
+                        .prepareStatement(CREATE_SQL, Statement.RETURN_GENERATED_KEYS)) {
+            statement.setString(1, book.getTitle());
+            statement.setBigDecimal(2, book.getPrice());
+            int rowsAffected = statement.executeUpdate();
+            if (rowsAffected < 1) {
+                throw new DataProcessingException("At least one row was expected to be affected, "
+                        + "but 0 rows were affected");
+            }
+            ResultSet generatedKeys = statement.getGeneratedKeys();
+            if (generatedKeys.next()) {
+                book.setId(generatedKeys.getLong(1));
+            }
+        } catch (SQLException e) {
+            throw new DataProcessingException("An error occurred while creating the book", e);
+        }
+        return book;
+    }
+
+    @Override
+    public Optional<Book> findById(Long id) {
+        Book book = new Book();
+        try (Connection connection = ConnectionUtil.getConnection();
+                PreparedStatement statement = connection
+                        .prepareStatement(FIND_BY_ID_SQL)) {
+            statement.setObject(1, id, Types.BIGINT);
+            ResultSet resultSet = statement.executeQuery();
+            if (resultSet.next()) {
+                book = mapResultSet(resultSet);
+            }
+        } catch (SQLException e) {
+            throw new DataProcessingException("Could not find book with id: " + id, e);
+        }
+        return Optional.of(book);
+    }
+
+    @Override
+    public List<Book> findAll() {
+        try (Connection connection = ConnectionUtil.getConnection();
+                PreparedStatement statement = connection.prepareStatement(FIND_ALL_SQL)) {
+            List<Book> books = new ArrayList<>();
+            ResultSet resultSet = statement.executeQuery();
+            while (resultSet.next()) {
+                Book book = mapResultSet(resultSet);
+                books.add(book);
+            }
+            return books;
+        } catch (SQLException e) {
+            throw new DataProcessingException("Could not find all book", e);
+        }
+    }
+
+    @Override
+    public Book update(Book book) {
+        try (Connection connection = ConnectionUtil.getConnection();
+                PreparedStatement statement = connection.prepareStatement(UPDATE_BY_ID_SQL)) {
+            statement.setObject(1, book.getTitle(), Types.VARCHAR);
+            statement.setObject(2, book.getPrice(), Types.DECIMAL);
+            statement.setObject(3, book.getId(), Types.BIGINT);
+
+            int rowsAffected = statement.executeUpdate();
+            if (rowsAffected < 1) {
+                throw new DataProcessingException("At least one row was expected to be affected, "
+                        + "but 0 rows were affected");
+            }
+        } catch (SQLException e) {
+            throw new DataProcessingException("An error occurred while updating the book", e);
+        }
+        return book;
+    }
+
+    @Override
+    public boolean deleteById(Long id) {
+        try (Connection connection = ConnectionUtil.getConnection();
+                PreparedStatement statement = connection.prepareStatement(DELETE_BY_ID_SQL)) {
+            statement.setObject(1, id, Types.BIGINT);
+            return statement.executeUpdate() > 0;
+        } catch (SQLException e) {
+            throw new DataProcessingException("An error occurred while deleting the book", e);
+        }
+    }
+
+    private Book mapResultSet(ResultSet resultSet) throws SQLException {
+        Book book = new Book();
+        book.setId(resultSet.getLong("id"));
+        book.setTitle(resultSet.getString("title"));
+        book.setPrice(resultSet.getBigDecimal("price"));
+        return book;
+    }
+}

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

@@ -0,0 +1,50 @@
+package mate.academy.entity;
+
+import java.math.BigDecimal;
+
+public class Book {
+    private Long id;
+    private String title;
+    private BigDecimal price;
+
+    public Book() {
+    }
+
+    public Book(String title, BigDecimal price) {
+        this.title = title;
+        this.price = price;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public String getTitle() {
+        return title;
+    }
+
+    public void setTitle(String title) {
+        this.title = title;
+    }
+
+    public BigDecimal getPrice() {
+        return price;
+    }
+
+    public void setPrice(BigDecimal price) {
+        this.price = price;
+    }
+
+    @Override
+    public String toString() {
+        return "Book{"
+                + "id=" + id
+                + ", title='" + title + '\''
+                + ", price=" + price
+                + '}';
+    }
+}

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

@@ -0,0 +1,11 @@
+package mate.academy.exception;
+
+public class DataProcessingException extends RuntimeException {
+    public DataProcessingException(String cause, Throwable e) {
+        super(cause, e);
+    }
+
+    public DataProcessingException(String cause) {
+        super(cause);
+    }
+}

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

@@ -0,0 +1,27 @@
+package mate.academy.util;
+
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.SQLException;
+import java.util.Properties;
+
+public class ConnectionUtil {
+    private static final String DB_URL = "jdbc:mysql://localhost:3306/books";
+    private static final Properties DB_PROPERTIES;
+
+    static {
+        DB_PROPERTIES = new Properties();
+        DB_PROPERTIES.put("user", "root");
+        DB_PROPERTIES.put("password", "6855");
+
+        try {
+            Class.forName("com.mysql.cj.jdbc.Driver");
+        } catch (ClassNotFoundException e) {
+            throw new RuntimeException("Can`t load JDBC driver", e);
+        }
+    }
+
+    public static Connection getConnection() throws SQLException {
+        return DriverManager.getConnection(DB_URL, DB_PROPERTIES);
+    }
+}

src/main/resources/init_db.sql

@@ -0,0 +1,5 @@
+CREATE TABLE book (
+    id BIGINT AUTO_INCREMENT PRIMARY KEY,
+    title VARCHAR(255),
+    price DECIMAL
+);