import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

public class Java_3{

public static void main(String[] args){

MulticastFrame frame = new MulticastFrame();

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.show();

}

}

class MulticastFrame extends JFrame{

public MulticastFrame(){

setTitle("MulticastTest");

setSize(WIDTH, HEIGHT);

MulticastPanel panel = new MulticastPanel();

Container contentPane = getContentPane();

//*********Found**********

contentPane.add(panel);

}

public static final int WIDTH = 300;

public static final int HEIGHT = 200;

}

class MulticastPanel extends JPanel{

public MulticastPanel(){

JButton newButton = new JButton("New");

add(newButton);

ActionListener newListener = new ActionListener(){

public void actionPerformed(ActionEvent event){

makeNewFrame();

}

};

newButton.addActionListener(newListener);

closeAllButton = new JButton("Close all");

add(closeAllButton);

}

private void makeNewFrame(){

final BlankFrame frame = new BlankFrame();

frame.show();

ActionListener closeAllListener = new ActionListener(){

public void actionPerformed(ActionEvent event){

//*********Found**********

frame.setVisible(false);     //使窗口隐藏或消除

}

};

//*********Found**********

closeAllButton.addActionListener(closeAllListener);

}

private JButton closeAllButton;

}

class BlankFrame extends JFrame{

public BlankFrame(){

//*********Found**********

counter ++ ;

setTitle("Frame " + counter);

setSize(WIDTH, HEIGHT);

setLocation(SPACING * counter, SPACING * counter);

}

public static final int WIDTH = 200;

public static final int HEIGHT = 150;

public static final int SPACING = 30;

private static int counter = 0;

}