1 /* 2 * Copyright (c) 2000, 2004, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package java.util; 27 28 /** 29 * An abstract wrapper class for an {@code EventListener} class 30 * which associates a set of additional parameters with the listener. 31 * Subclasses must provide the storage and accessor methods 32 * for the additional arguments or parameters. 33 * <p> 34 * For example, a bean which supports named properties 35 * would have a two argument method signature for adding 36 * a {@code PropertyChangeListener} for a property: 37 * <pre> 38 * public void addPropertyChangeListener(String propertyName, 39 * PropertyChangeListener listener) 40 * </pre> 41 * If the bean also implemented the zero argument get listener method: 42 * <pre> 43 * public PropertyChangeListener[] getPropertyChangeListeners() 44 * </pre> 45 * then the array may contain inner {@code PropertyChangeListeners} 46 * which are also {@code PropertyChangeListenerProxy} objects. 47 * <p> 48 * If the calling method is interested in retrieving the named property 49 * then it would have to test the element to see if it is a proxy class. 50 * 51 * @since 1.4 52 */ 53 public abstract class EventListenerProxy<T extends EventListener> 54 implements EventListener { 55 56 private final T listener; 57 58 /** 59 * Creates a proxy for the specified listener. 60 * 61 * @param listener the listener object 62 */ 63 public EventListenerProxy(T listener) { 64 this.listener = listener; 65 } 66 67 /** 68 * Returns the listener associated with the proxy. 69 * 70 * @return the listener associated with the proxy 71 */ 72 public T getListener() { 73 return this.listener; 74 } 75 } 76
