import java.lang.reflect.*;


import java.awt.*;
import java.awt.event.*;

import javax.swing.*;
import javax.swing.event.*;




public class Demo
{
    JPanel root = new JPanel(new BorderLayout());
    JLabel label = new JLabel(" ");

    public void button1Action(ActionEvent e) {
	label.setText("button1Action - normal listener class ");
    }

    public void button2Action(ActionEvent e) {
	label.setText("button2Action - dynamically generated listener class");
    }

    public void rootMouseEntered(MouseEvent e) {
	label.setText(e.toString());
    }

    Demo() {
	JButton button1 = new JButton("Button1: Normal Listener");
	JButton button2 = new JButton("Button2: Dynamic Listener");

	/* This listener is of the conventional variety.  It causes 
	 * a new (inner) class to be generated which the compiler 
	 * may put in a separate file with funny name like Demo$1.class.
	 */
	ActionListener button1ActionListener = new ActionListener() {
	    public void actionPerformed(ActionEvent e) {
		button1Action(e);
	    }
	};

	button1.addActionListener(button1ActionListener);
	
	/* This listener will be generated at run-time, i.e. at run-time
	 * an ActionListener class will be code-generated and then 
	 * class-loaded.  Only one of these is actually created, even
	 * if many calls to GenericListener.create(ActionListener.class ...)
	 * are made.
	 */
	ActionListener button2ActionListener = (ActionListener)(GenericListener.create(
	        ActionListener.class,
		"actionPerformed",
		this,
		"button2Action"));

	button2.addActionListener(button2ActionListener);
	
	JPanel buttons = new JPanel();
	buttons.add(button1);
	buttons.add(button2);

	/* Here's another dynamically generated listener.  This one is
	 * a little different because the listenerMethod argument actually
	 * specifies one of many listener methods.  In the previous example
	 * "actionPerformed" named the one and only ActionListener method.
	 */
	MouseListener rootMouseListener = (MouseListener)(GenericListener.create(
	        MouseListener.class,
		"mouseEntered",
		this,
		"rootMouseEntered"));

	root.addMouseListener(rootMouseListener);
	
	root.add(buttons, BorderLayout.CENTER);
	root.add(label, BorderLayout.SOUTH);
    }

    public static void main(String[] args) {
	WindowListener l = new WindowAdapter() {
	    public void windowClosing(WindowEvent e) {
		System.exit(0);
	    }
	};
	JFrame f = new JFrame("Demo");
	f.addWindowListener(l); 
	f.getContentPane().add(new Demo().root, BorderLayout.CENTER);
	f.pack();
	f.setVisible(true);
    }
}