eventlistenerproxy.java

来自「java源代码 请看看啊 提点宝贵的意见」· Java 代码 · 共 54 行

/*
 * @(#)EventListenerProxy.java	1.3 03/01/23
 *
 * Copyright 2003 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package java.util;

/**
 * An abstract wrapper class for an EventListener class which associates a set
 * of additional parameters with the listener. Subclasses must provide the
 * storage and accessor methods for the additional arguments or parameters.
 * 
 * Subclasses of EventListerProxy may be returned by getListeners() methods
 * as a way of associating named properties with their listeners.
 * 
 * For example, a Bean which supports named properties would have a two
 * argument method signature for adding a PropertyChangeListener for a
 * property:
 * 
 *     public void addPropertyChangeListener(String propertyName,
 *                                  PropertyChangeListener listener);
 * 
 * If the Bean also implemented the zero argument get listener method:
 * 
 *     public PropertyChangeListener[] getPropertyChangeListeners();
 *
 * then the array may contain inner PropertyChangeListeners which are also 
 * PropertyChangeListenerProxy objects.
 * 
 * If the calling method is interested in retrieving the named property then it
 * would have to test the element to see if it is a proxy class.
 * 
 * @since 1.4
 */
public abstract class EventListenerProxy implements EventListener {
    private final EventListener listener;

    /**
     * @param listener The listener object.
     */ 
    public EventListenerProxy(EventListener listener) {
        this.listener = listener;
    }

    /**
     * @return The listener associated with this proxy.
     */
    public EventListener getListener() {
        return listener;
    }
}