/**
 * Illustrates the paint method for Container objects (MainWindow
 * is a great-grandchild subclass of Container, and thus
 * has a paint method).
 *
 * 0. Compile and run PaintedWindowTester.  Cover up the output window with
 * some other window and then bring the output window forward again.
 * Isn't that nice?
 * 
 * 1. First of all, PaintedWindow is a kind of MainWindow--technically,
 * we say that PaintedWindow is a "subclass" of MainWindow.  Therefore,
 * any method you can call for a MainWindow object, you can also call
 * for a PaintedWindow object.  Note the "extends" construction that sets
 * up this class/subclass (or parent/child) relationship.
 * 
 * 2. Since PaintedWindow is a MainWindow, and MainWindow has several
 * constructors, PaintedWindow might want to invoke one of those constructors.
 * To invoke a constructor from the parent class, you use the "super"
 * construction.  If you comment out the "super( title );" line below,
 * what happens?
 * 
 * 3. Note that you can put setVisible( true ) in the constructor.  This makes
 * your window a little less of a hassle to use.
 * 
 * 4. Try changing the color in the setBackground method call.
 * 
 * 5. Go to Wu's javabook documentation and take a look at the MainWindow
 * class.  At the top of the page, you should see MainWindow's geneology.
 * For example, MainWindow is a subclass of Frame.  Since a PaintedWindow is
 * a MainWindow and a MainWindow is a Frame, a PaintedWindow is a Frame
 * (and a Window, and a Container, and...).  Look through the MainWindow
 * documentation--which ancestor class provides the "paint" method?
 * Open Sun's Java documentation and find the paint method.  Is its description
 * helpful?
 * 
 * 6. Put System.out.println( "Painting" ); inside the paint method and run
 * the program.  Experiment with moving windows around on top of the PaintedWindow.
 * When does paint get called?  When does it not get called?
 *
 * Also shows how to call a superclass constructor.
 *
 * @author Jeff Ondich
 */

import java.awt.*;
import javabook.*;

class PaintedWindow extends MainWindow
{
	public PaintedWindow( String title )
	{
		super( title );
		setVisible( true );
		setBackground( Color.white );
	}

	// Whenever a portion of the window object is uncovered,
	// this method gets called.
    public void paint( Graphics g )
    {
		g.setColor( Color.cyan );
		g.fillOval( 300, 300, 150, 150 );
	}
}