GUIs - Multimedia Introduction to Programming Using Java - page 458

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

public class MouseDemo extends JFrame {
Box leftColumn= new Box(BoxLayout.Y_AXIS);
Square b00= new Square(0,0);
Square b01= new Square(0,1);
Box rightColumn= new Box(BoxLayout.Y_AXIS);
Square b10= new Square(1,0);
Square b11= new Square(1,1);

JButton jb= new JButton("initialize");
Box b= new Box(BoxLayout.X_AXIS);
/** Constructor: an invisible JFrame with title t */
public MouseDemo(String t) {
super (t);
leftColumn.add(b00);
leftColumn.add(b01);
b.add(leftColumn);
rightColumn.add(b10);
rightColumn.add(b11);
b.add(rightColumn);
Container cp= getContentPane();
cp.add(b, BorderLayout.CENTER);
cp.add(jb, BorderLayout.SOUTH);
jb.addActionListener( new ButtonListener());
pack();
setResizable( false );

}
/** Respond to mouse click on button jb */
public class ButtonListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
b00.clearDisk();
b01.clearDisk();
b10.clearDisk();
b11.clearDisk();

}

}

}

Figure 17.17: Class MouseDemo