create Book entity and implement BookDao repository interface

pom.xml

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

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

@@ -0,0 +1,28 @@
+package mate.academy;
+
+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/ma_db";
+    private static final Properties DB_PROPERTIES;
+
+    static {
+        DB_PROPERTIES = new Properties();
+        DB_PROPERTIES.put("user", "bestuser");
+        DB_PROPERTIES.put("password", "bestuser");
+
+        try {
+            Class.forName("com.mysql.cj.jdbc.Driver");
+        } catch (ClassNotFoundException e) {
+            throw new RuntimeException("Can not load JDBC Driver", e);
+        }
+    }
+
+    public static Connection getConnection() throws SQLException {
+        return DriverManager
+                .getConnection(DB_URL, DB_PROPERTIES);
+    }
+}

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

@@ -1,7 +1,39 @@
 package mate.academy;
 
+import java.math.BigDecimal;
+import java.util.List;
+import java.util.Optional;
+import mate.academy.dao.BookDao;
+import mate.academy.lib.Injector;
+import mate.academy.models.Book;
+
 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) {
+        System.out.println("Creating a new book:");
+        BookDao bookDao = (BookDao) injector.getInstance(BookDao.class);
+        Book book = new Book();
+        book.setTitle("Treasure Island");
+        book.setPrice(BigDecimal.valueOf(1500));
+        System.out.println(bookDao.create(book));
+        System.out.println("Getting book by id:");
+        Optional<Book> optionalBook = bookDao.findById(3L);
+        System.out.println(optionalBook.orElseThrow());
+        System.out.println("Getting all books:");
+        List<Book> books = bookDao.findAll();
+        for (Book row : books) {
+            System.out.println(row);
+        }
+        System.out.println("Book with id = 1 before updating:");
+        System.out.println(bookDao.findById(4L).orElseThrow());
+        System.out.println("Book with id = 1 after updating:");
+        Book updatedBook = new Book();
+        updatedBook.setId(4L);
+        updatedBook.setTitle("New title");
+        updatedBook.setPrice(BigDecimal.valueOf(2000));
+        System.out.println(bookDao.update(updatedBook));
+        System.out.println("Deleting book with id = 1:");
+        System.out.println(bookDao.deleteById(4L));
     }
 }

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.models.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.math.BigDecimal;
+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 mate.academy.ConnectionUtil;
+import mate.academy.exception.DataProcessingException;
+import mate.academy.lib.Dao;
+import mate.academy.models.Book;
+
+@Dao
+public class BookDaoImpl implements BookDao {
+    @Override
+    public Book create(Book book) {
+        String sql = "INSERT INTO books (title, price) VALUES (?,?)";
+        Throwable ex = null;
+        try (Connection connection = ConnectionUtil.getConnection();
+                PreparedStatement statement = connection.prepareStatement(sql,
+                        Statement.RETURN_GENERATED_KEYS)) {
+            statement.setString(1, book.getTitle());
+            statement.setObject(2, book.getPrice());
+            int affectedRows = statement.executeUpdate();
+            if (affectedRows < 1) {
+                throw new DataProcessingException("Expected to insert at least one row, "
+                        + "but inserted 0 rows.", ex);
+            }
+            ResultSet generatedKeys = statement.getGeneratedKeys();
+            if (generatedKeys.next()) {
+                Long id = generatedKeys.getObject(1, Long.class);
+                book.setId(id);
+            }
+        } catch (SQLException e) {
+            throw new DataProcessingException("Can't add new book", e);
+        }
+        return book;
+    }
+
+    @Override
+    public Optional<Book> findById(Long id) {
+        String sql = "SELECT * FROM books WHERE id = ?";
+        try (Connection connection = ConnectionUtil.getConnection();
+                PreparedStatement statement = connection.prepareStatement(sql)) {
+            statement.setLong(1, id);
+            ResultSet resultSet = statement.executeQuery();
+            if (resultSet.next()) {
+                String title = resultSet.getString("title");
+                BigDecimal price = resultSet.getBigDecimal("price");
+                Book book = new Book();
+                book.setId(id);
+                book.setTitle(title);
+                book.setPrice(price);
+                return Optional.of(book);
+            }
+        } catch (SQLException e) {
+            throw new DataProcessingException("Can not find a book with ID: " + id, e);
+        }
+        return Optional.empty();
+    }
+
+    @Override
+    public List<Book> findAll() {
+        List<Book> books = new ArrayList<>();
+        String sql = "SELECT * FROM books";
+        try (Connection connection = ConnectionUtil.getConnection();
+                PreparedStatement statement = connection.prepareStatement(sql)) {
+            ResultSet resultSet = statement.executeQuery();
+            while (resultSet.next()) {
+                Book book = new Book();
+                book.setId(resultSet.getLong(1));
+                book.setTitle(resultSet.getString(2));
+                book.setPrice(resultSet.getBigDecimal(3));
+                books.add(book);
+            }
+        } catch (SQLException e) {
+            throw new DataProcessingException("Can't get books", e);
+        }
+        return books;
+    }
+
+    @Override
+    public Book update(Book book) {
+        String sql = "UPDATE books SET title = ?, price = ? WHERE id = ?";
+        Throwable ex = null;
+        try (Connection connection = ConnectionUtil.getConnection();
+                PreparedStatement statement = connection.prepareStatement(sql)) {
+            statement.setLong(3, book.getId());
+            statement.setString(1, book.getTitle());
+            statement.setBigDecimal(2, book.getPrice());
+            int affectedRows = statement.executeUpdate();
+            if (affectedRows < 1) {
+                throw new DataProcessingException("Cannot update a book with ID: " + book.getId(),
+                        ex);
+            }
+        } catch (SQLException e) {
+            throw new DataProcessingException("Can't get the books", e);
+        }
+        return book;
+    }
+
+    @Override
+    public boolean deleteById(Long id) {
+        String sql = "DELETE FROM books WHERE id = ?";
+        try (Connection connection = ConnectionUtil.getConnection();
+                PreparedStatement statement = connection.prepareStatement(sql)) {
+            statement.setLong(1, id);
+            int affectedRows = statement.executeUpdate();
+            return affectedRows > 0;
+        } catch (SQLException e) {
+            throw new DataProcessingException("Can't delete book with ID: " + id, e);
+        }
+    }
+}

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

@@ -0,0 +1,7 @@
+package mate.academy.exception;
+
+public class DataProcessingException extends RuntimeException {
+    public DataProcessingException(String message, Throwable ex) {
+        super(message, ex);
+    }
+}

src/main/java/mate/academy/lib/Injector.java

@@ -15,6 +15,7 @@ public class Injector {
     private final List<Class<?>> classes = new ArrayList<>();
 
     private Injector(String mainPackageName) {
+        System.out.println("Initializing Injector for package: " + mainPackageName);
         try {
             classes.addAll(getClasses(mainPackageName));
         } catch (IOException | ClassNotFoundException e) {
@@ -73,6 +74,7 @@ private Object createInstance(Class<?> clazz) {
      */
     private static List<Class<?>> getClasses(String packageName)
             throws IOException, ClassNotFoundException {
+        System.out.println("Getting classes for package: " + packageName);
         ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
         if (classLoader == null) {
             throw new RuntimeException("Class loader is null");
@@ -82,7 +84,10 @@ private static List<Class<?>> getClasses(String packageName)
         List<File> dirs = new ArrayList<>();
         while (resources.hasMoreElements()) {
             URL resource = resources.nextElement();
-            dirs.add(new File(resource.getFile()));
+            String decodedPath = java.net.URLDecoder.decode(resource.getFile(), "UTF-8");
+            System.out.println("Decoded Resource: " + decodedPath);
+            System.out.println("Resource: " + resource.getFile());
+            dirs.add(new File(decodedPath));
         }
         ArrayList<Class<?>> classes = new ArrayList<>();
         for (File directory : dirs) {
@@ -103,8 +108,10 @@ private static List<Class<?>> findClasses(File directory, String packageName)
             throws ClassNotFoundException {
         List<Class<?>> classes = new ArrayList<>();
         if (!directory.exists()) {
+            System.out.println("Directory does not exist: " + directory.getAbsolutePath());
             return classes;
         }
+        System.out.println("Scanning directory: " + directory.getAbsolutePath());
         File[] files = directory.listFiles();
         if (files != null) {
             for (File file : files) {
@@ -115,6 +122,7 @@ private static List<Class<?>> findClasses(File directory, String packageName)
                     classes.addAll(findClasses(file, packageName + "."
                             + file.getName()));
                 } else if (file.getName().endsWith(".class")) {
+                    System.out.println("Found class file: " + file.getName());
                     classes.add(Class.forName(packageName + '.'
                             + file.getName().substring(0, file.getName().length() - 6)));
                 }

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

@@ -0,0 +1,42 @@
+package mate.academy.models;
+
+import java.math.BigDecimal;
+
+public class Book {
+    private Long id;
+    private String title;
+    private BigDecimal 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/resources/init_db.sql

@@ -0,0 +1,8 @@
+CREATE TABLE `books` (
+    `id` INT NOT NULL AUTO_INCREMENT,
+    `title` VARCHAR(255),
+    `price` DECIMAL,
+    PRIMARY KEY (`id`)
+);
+
+USE ma_db;