// SwingGUIsFrameDemoOneInnerClass.java
// One JButton widget in a JFrame.  similar to SwingGUIsFrameDemoOne.java
//**but ActionListener is an anonymous inner class (instead of "this" ).
//  anonymous: has no name.  compiler creates name of class file with $1.
//  inner class: a class defined inside another class.

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

public class SwingGUIsFrameDemoOneInnerClass { 
    //** does NOT implement ActionListener 

    private JFrame outputFrame;
    private Container container;
    private JButton myButton;

    public static void main( String [] args ) {
	SwingGUIsFrameDemoOneInnerClass myFrameDemo = 
                new SwingGUIsFrameDemoOneInnerClass();
    }
    
    //constructor
    public SwingGUIsFrameDemoOneInnerClass() {
	outputFrame = new JFrame();
	outputFrame.setSize(600,500);
	outputFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
	
	container = outputFrame.getContentPane();  
	container.setLayout( new FlowLayout() );  
	
	myButton = new JButton( "My JButton" );
	container.add( myButton );
        //**handler is actionPerformed method of object of anonymous inner class 
	//that implements ActionListener interface is defined and instantiated
	//in the parameter of addActionListener method.
	myButton.addActionListener(           //method call
	    new ActionListener() {     //instantiate object
	        public void actionPerformed( ActionEvent event ) {
		    JOptionPane.showMessageDialog(null,"myButton got it");
		}
	    }
	);  //end of addActionListener method call

	//** useful for having action listener per widget:
	//myWidget.addActionListener(new ActionListener(){...});

	//it's a common way to do the event handling.
	//it's a common use of anonymous inner classes.

	outputFrame.setVisible(true);
    }
}