/** ClickMe.java
    This program is a very simple event driven Java program.
    It contains a single button, that when clicked pops open a message dialog.

    Written by: Stuart Hansen
    Date: September 2008
**/

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

public class ClickMe extends JFrame {
   JButton button;  // Our one and only button

   public ClickMe () {
      // The button is our event source
      button = new JButton("Click me");

      // We register a handler with the source
      ActionHandler handler = new ActionHandler();
      button.addActionListener(handler);

      // We add the button to the viewable area of the window
      getContentPane().add(button);

      // We set a couple of window properties and then open the main window
      setSize(100, 100);
      setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      setVisible(true);
   }
     
   // Event driven program regularly have incredibly simple main programs
   public static void main (String args[]) {
      new ClickMe();
   }    
}

// The handler class.
class ActionHandler implements ActionListener {
   public void actionPerformed (ActionEvent e) {
      JOptionPane.showMessageDialog(null, "Ouch! That hurt.");
   }
}