/*
 * @(#)BeanContextEvent.java	1.9 00/02/02
 *
 * Copyright 1997-2000 Sun Microsystems, Inc. All Rights Reserved.
 * 
 * This software is the proprietary information of Sun Microsystems, Inc.  
 * Use is subject to license terms.
 * 
 */

package java.beans.beancontext;

import java.util.EventObject;

import java.beans.beancontext.BeanContext;

/**
 * <p>
 * <code>BeanContextEvent</code> is the abstract root event class 
 * for all events emitted
 * from, and pertaining to the semantics of, a <code>BeanContext</code>.
 * This class introduces a mechanism to allow the propagation of 
 * <code>BeanContextEvent</code> subclasses through a heirarchy of 
 * <code>BeanContext</code>s. The <code>setPropagatedFrom()</code> 
 * and <code>getPropagatedFrom()</code> methods allow a 
 * <code>BeanContext</code> to identify itself as the source 
 * of a propagated event. 
 * </p>
 *
 * @author	Laurence P. G. Cable
 * @version	1.9, 02/02/00
 * @since	1.2
 * @see		java.beans.beancontext.BeanContext
 */

public abstract class BeanContextEvent extends EventObject {

    /**
     * Contruct a BeanContextEvent
     *
     * @param bc	The BeanContext source
     */
    protected BeanContextEvent(BeanContext bc) {
	super(bc);
    }

    /**
     * Gets the <code>BeanContext</code> associated with this event.
     * @return the <code>BeanContext</code> associated with this event.
     */
    public BeanContext getBeanContext() { return (BeanContext)getSource(); }

    /**
     * Sets the <code>BeanContext</code> from which this event was propagated.
     * @param bc the <code>BeanContext</code> from which this event 
     * was propagated
     */
    public synchronized void setPropagatedFrom(BeanContext bc) {
	propagatedFrom = bc;
    }

    /**
     * Gets the <code>BeanContext</code> from which this event was propagated.
     * @param bc The <code>BeanContext</code> that last 
     * propagated this <code>BeanContextEvent</code>
     * @return the <code>BeanContext</code> from which this 
     * event was propagated
     */
    public synchronized BeanContext getPropagatedFrom() {
	return propagatedFrom;
    }

    /**
     * Reports whether or not this event is 
     * propagated from some other <code>BeanContext</code>.
     * @return <code>true</code> if propagated, <code>false</code> 
     * if not
     */
    public synchronized boolean isPropagated() {
	return propagatedFrom != null;
    }

    /*
     * fields
     */

    /** 
     * The <code>BeanContext</code> from which this event was propagated
     */
    protected BeanContext propagatedFrom;
}