Exceptions - Java Software Solutions: Foundations of Program Design - page 559

There are actually two images of the light bulb: one showing it turned on and
one showing it turned off. These images are brought in as ImageIcon objects. The
setIcon method of the label that displays the image is used to set the appropri-
ate image, depending on the current status. This processing is controlled in the
LightBulbPanel class shown in Listing 11.9.
LISTING 11.8
//********************************************************************
// LightBulb.java Author: Lewis/Loftus
//
// Demonstrates mnemonics and tool tips.
//********************************************************************
import javax.swing.*;
import java.awt.*;
public class LightBulb
{
//-----------------------------------------------------------------
// Sets up a frame that displays a light bulb image that can be
// turned on and off.
//-----------------------------------------------------------------
public static void main (String[] args)
{
JFrame frame = new JFrame ("Light Bulb");
frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
LightBulbPanel bulb = new LightBulbPanel();
LightBulbControls controls = new LightBulbControls (bulb);
JPanel panel = new JPanel();
panel.setBackground (Color.black);
panel.setLayout ( new BoxLayout(panel, BoxLayout.Y_AXIS));
panel.add (Box.createRigidArea ( new Dimension (0, 20)));
panel.add (bulb);
panel.add (Box.createRigidArea ( new Dimension (0, 10)));
panel.add (controls);
panel.add (Box.createRigidArea ( new Dimension (0, 10)));
frame.getContentPane().add(panel);
frame.pack();
frame.setVisible( true );
}
}