/**
 * PropertyPanel is the parent of panels that throw PropertyEvents.<p>
 *
 * Copyright &copy; 1998-89 Martin Minow. All Rights Reserved.<p>
 *
 * Permission to use, copy, modify, and redistribute this software and its
 * documentation for personal, non-commercial use is hereby granted provided that
 * this copyright notice and appropriate documentation appears in all copies. This
 * software may not be distributed for fee or as part of commercial, "shareware,"
 * and/or not-for-profit endevors including, but not limited to, CD-ROM collections,
 * online databases, and subscription services without specific license.<p>
 *
 * Based on DateGUI.java in Mastering JavaBeans.
 * @see <a href="http://www.sybase.com">Sybase</a>, click on
 *  "Catalog>Updates>Mastering JavaBeans".
 * @author <a href="mailto:minow@pobox.com">Martin Minow</a>
 * @version 1.0a0
 * Set tabs every 8 characters.
 */
package org.minow.applets.sunsphere;
import java.beans.*;
import java.util.*;
import java.awt.*;
import java.awt.event.*;
import java.text.*;

public abstract class PropertyPanel extends Panel
{
    /**
     * PropertyPanel is the parent of Component classes that
     * distribute user interaction by sending a PropertyChangeEvent.
     * Instead of sub-classing Panel, just subclass PropertyPanel.
     * When you need to distribute an event, call the (parent)
     * firePropertyChange method. PropertyPanel implements several
     * methods from java.beans.PropertyChangeSupport:
     *	addPropertyChangeListener
     *	removePropertyChangeListener,
     *	firePropertyChange
     */
 
    /*
     * PropertyChange message distributor.
     */
    protected PropertyChangeSupport	butler = new PropertyChangeSupport(this);
    
    /**
     * Subclasses call firePropertyChange to send a PropertyChange event
     * to their listeners.
     */
    protected void firePropertyChange(
    	    String		propertyName,
    	    Object		oldValue,
    	    Object		newValue
    	)
    {
	butler.firePropertyChange(propertyName, oldValue, newValue);
    }
    /**
     * PropertyPanel subclass users call addPropertyChange to add
     * (usually) themselves to the notification list.
     */
    public void addPropertyChangeListener(
	    PropertyChangeListener  listener
	)
    {
	butler.addPropertyChangeListener(listener);
    }
    /**
     * PropertyPanel subclass users call removePropertyChange to
     * remove (usually) themselves to the notification list.
     */
    public void removePropertyChangeListener(
	    PropertyChangeListener  listener
	)
    {
	butler.removePropertyChangeListener(listener);
    }
}