Java SE (Java Platform, Standard Edition)

Hi, I have just learn java swing and now creating a chess game. I have sucessfully create a board and able to display chess pieces on the board. By using JLayeredPane, I am able to use drag and drop for the piece. However, there is a problem which is that I can drop the chess piece off the board and the piece would disappear. I have try to solve this problem by trying to find the location that the chess piece is on, store it somewhere and check if the chess piece have been drop off bound. However, I could not manage to solve it. Also, I am very confuse with all these layer thing.

Any suggestion would be very helpful. Thanks in advance

import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;

public class ChessBoard extends JFrame implements MouseListener, MouseMotionListener
{
Object currentPosition;
Color currentColor;
Dimension boardSize = new Dimension(600, 600);
JLayeredPane layeredPane;
JPanel board;
JPanel box;
JLabel chessPiece;
int xAdjustment;
int yAdjustment;

public ChessBoard()
{
// Use a Layered Pane for this this application
layeredPane = new JLayeredPane();
getContentPane().add(layeredPane);
layeredPane.setPreferredSize( boardSize );
layeredPane.addMouseListener( this );
layeredPane.addMouseMotionListener( this );

// Add a chess board to the Layered Pane
board = new JPanel();

// set "board" to the lowest layer (default_layer)
layeredPane.add(board, JLayeredPane.DEFAULT_LAYER);
board.setLayout( new GridLayout(8, 8) );
board.setPreferredSize( boardSize );
board.setBounds(0, 0, boardSize.width, boardSize.height);

addShade();
addPiece();
}


public void addShade()
{
for (int i = 0; i < 64; i++)
{
box = new JPanel( new BorderLayout() );
board.add( box, BorderLayout.CENTER );

if( ((i / 8) % 2) == 0)
{
if( (i % 2) ==0)
{
box.setBackground(Color.lightGray);
} else {
box.setBackground( Color.white);
}
} else {
if( (i % 2) ==0)
{
box.setBackground(Color.white);
} else {
box.setBackground(Color.lightGray);
}
}
}
}

//Method for adding chess pieces to the board
public void addPiece()
{
// Add a few pieces to the board
//black pieces
for (int i = 0; i < 64; i++)
{
//adding black pieces
if (i < 8)
{
String fileName = i + ".gif";
JLabel blackPieces = new JLabel( new ImageIcon( fileName ) );
JPanel panel = (JPanel)board.getComponent( i );
panel.add( blackPieces );
}

//adding black pones
if ((i > 7) && (i < 16))
{
String fileName = "8.gif";
JLabel blackPones = new JLabel( new ImageIcon( fileName ) );
JPanel panel = (JPanel)board.getComponent( i );
panel.add( blackPones );
}

//jump to white position (Component 48)
if (i == 16) i = 48;

//adding white pones
if(( i > 47 ) && (i < 56))
{
JLabel whitePones = new JLabel( new ImageIcon("48.gif") );
JPanel panel = (JPanel)board.getComponent( i );
panel.add( whitePones );
}

//adding white pieces
if (i > 55)
{
String fileName = i + ".gif";
JLabel whitePieces = new JLabel( new ImageIcon( fileName ) );
JPanel panel = (JPanel)board.getComponent( i);
panel.add( whitePieces );
}
}

}

/*
** Add the selected chess piece to the dragging layer so it can be moved
*/
public void mousePressed(MouseEvent e)
{
chessPiece = null;
Component c = board.findComponentAt(e.getX(), e.getY());

c.setBackground(Color.red);
if (c instanceof JPanel) return;

Point parentLocation = c.getParent().getLocation();
xAdjustment = parentLocation.x - e.getX();
yAdjustment = parentLocation.y - e.getY();
chessPiece = (JLabel)c;
chessPiece.setLocation(e.getX() + xAdjustment, e.getY() + yAdjustment);
chessPiece.setSize(chessPiece.getWidth(), chessPiece.getHeight());
layeredPane.add(chessPiece, JLayeredPane.DRAG_LAYER);
}

/*
** Move the chess piece around
*/
public void mouseDragged(MouseEvent me)
{
if (chessPiece == null) return;
chessPiece.setLocation(me.getX() + xAdjustment, me.getY() + yAdjustment);
}

/*
** Drop the chess piece back onto the chess board
*/
public void mouseReleased(MouseEvent e)
{
Component c = board.findComponentAt(e.getX(), e.getY());
int x = (int)c.getBounds().getX();
int y = (int)c.getBounds().getY();
System.out.println(c.getLocation());
System.out.println(x + " "+ y);

c.setBackground(currentColor);
if (chessPiece == null) return;

chessPiece.setVisible(false);

if (c instanceof JLabel)
{
Container parent = c.getParent();
//remove the piece that is capture
parent.remove(0);
parent.add( chessPiece );
}
else
{
Container parent = (Container)c;
parent.add( chessPiece );
}

chessPiece.setVisible(true);

}

public void mouseClicked(MouseEvent e) {}
public void mouseMoved(MouseEvent e) {}
public void mouseEntered(MouseEvent e) {}
public void mouseExited(MouseEvent e) {}

private static void createAndShowGUI()
{
//Make sure we have nice window decorations
JFrame.setDefaultLookAndFeelDecorated(true);

JFrame frame = new ChessBoard();
frame.setDefaultCloseOperation( JFrame.DISPOSE_ON_CLOSE );

//Display the window
frame.pack();
frame.setResizable( false );
frame.setLocationRelativeTo( null );
frame.setVisible(true);

}

public static void main(String[] args)
{
//Schedule a job for the event-dispatching thread:
//creating and showing this application's GUI
javax.swing.SwingUtilities.invokeLater( new Runnable()
{
public void run()
{
createAndShowGUI();
}
});
}
}