package ejava.examples.daoex.dao;
   
   import java.lang.reflect.Field;
   import java.sql.Connection;
   import java.sql.PreparedStatement;
   import java.sql.ResultSet;
   import java.sql.SQLException;
   import java.sql.Statement;
   import java.util.List;
  
  import javax.persistence.PersistenceException;
  
  import ejava.examples.daoex.bo.Book;
  
  public class JDBCBookDAOImpl implements BookDAO {
  	private Connection connection;
  	
  	public void setConnection(Connection connection) {
  		this.connection = connection;
  	}
  
  	@Override
  	public Book create(Book book) throws PersistenceException {
  		try (PreparedStatement insertStatement=getInsertPreparedStatement(connection, book);
  		     PreparedStatement idStatement=getIdentityStatement(connection)){
  			insertStatement.execute();
  			
              try (ResultSet rs = idStatement.executeQuery()) {
                  if (rs.next()) {
                      Field id = Book.class.getDeclaredField("id");
                      id.setAccessible(true);
                      id.set(book, rs.getLong(1));
                  } else {
                      throw new PersistenceException("no identity returned from database");
                  }                
              } catch (NoSuchFieldException ex) {
                  throw new PersistenceException("Error locating id field", ex);
              } catch (IllegalAccessException ex) {
                  throw new PersistenceException("Access error setting id", ex);
              }
  			
  			return book;
  		} catch (SQLException ex) { 
  			throw new PersistenceException("SQL error creating book", ex);
  		}
  	}
  	
  	private PreparedStatement getInsertPreparedStatement(Connection c, Book book) throws SQLException {
          PreparedStatement statement=connection.prepareStatement(
                  "insert into JPADAO_BOOK (ID, DESCRIPTION, PAGES, TITLE) " +
                  "values (null, ?, ?, ?)");
          statement.setString(1, book.getDescription());
          statement.setInt(2, book.getPages());
          statement.setString(3, book.getTitle());
          return statement;
  	}
  	
  	private PreparedStatement getIdentityStatement(Connection c) throws SQLException {
          PreparedStatement statement = connection.prepareStatement("call identity()");
          return statement;
  	}
  
  	@Override
  	public Book update(Book book) throws PersistenceException {
  		// TODO Auto-generated method stub
  		return null;
  	}
  
  	@Override
  	public Book get(long id) throws PersistenceException {
  		// TODO Auto-generated method stub
  		return null;
  	}
  
  	@Override
  	public void remove(Book book) throws PersistenceException {
  		// TODO Auto-generated method stub
  
  	}
  
  	@Override
  	public List<Book> findAll(int start, int count) throws PersistenceException {
  		// TODO Auto-generated method stub
  		return null;
  	}
  
  }