| /* |
| * Copyright (c) 2003, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package sun.awt; |
| |
| import java.lang.reflect.Array; |
| import java.util.EventListener; |
| |
| |
| /** |
| * A class that assists in managing {@link java.util.EventListener}s of |
| * the specified type. Its instance holds an array of listeners of the same |
| * type and allows to perform the typical operations on the listeners. |
| * This class is thread-safe. |
| * |
| * @author Alexander Gerasimov |
| * |
| * @since 1.5 |
| */ |
| public class EventListenerAggregate { |
| |
| private EventListener[] listenerList; |
| |
| /** |
| * Constructs an <code>EventListenerAggregate</code> object. |
| * |
| * @param listenerClass the type of the listeners to be managed by this object |
| * |
| * @throws NullPointerException if <code>listenerClass</code> is |
| * <code>null</code> |
| * @throws ClassCastException if <code>listenerClass</code> is not |
| * assignable to <code>java.util.EventListener</code> |
| */ |
| public EventListenerAggregate(Class listenerClass) { |
| if (listenerClass == null) { |
| throw new NullPointerException("listener class is null"); |
| } |
| |
| if (!EventListener.class.isAssignableFrom(listenerClass)) { |
| throw new ClassCastException("listener class " + listenerClass + |
| " is not assignable to EventListener"); |
| } |
| |
| listenerList = (EventListener[])Array.newInstance(listenerClass, 0); |
| } |
| |
| private Class getListenerClass() { |
| return listenerList.getClass().getComponentType(); |
| } |
| |
| /** |
| * Adds the listener to this aggregate. |
| * |
| * @param listener the listener to be added |
| * |
| * @throws ClassCastException if <code>listener</code> is not |
| * an instatce of <code>listenerClass</code> specified |
| * in the constructor |
| */ |
| public synchronized void add(EventListener listener) { |
| Class listenerClass = getListenerClass(); |
| |
| if (!listenerClass.isInstance(listener)) { // null is not an instance of any class |
| throw new ClassCastException("listener " + listener + " is not " + |
| "an instance of listener class " + listenerClass); |
| } |
| |
| EventListener[] tmp = (EventListener[])Array.newInstance(listenerClass, listenerList.length + 1); |
| System.arraycopy(listenerList, 0, tmp, 0, listenerList.length); |
| tmp[listenerList.length] = listener; |
| listenerList = tmp; |
| } |
| |
| /** |
| * Removes a listener that is equal to the given one from this aggregate. |
| * <code>equals()</code> method is used to compare listeners. |
| * |
| * @param listener the listener to be removed |
| * |
| * @return <code>true</code> if this aggregate contained the specified |
| * <code>listener</code>; <code>false</code> otherwise |
| * |
| * @throws ClassCastException if <code>listener</code> is not |
| * an instatce of <code>listenerClass</code> specified |
| * in the constructor |
| */ |
| public synchronized boolean remove(EventListener listener) { |
| Class listenerClass = getListenerClass(); |
| |
| if (!listenerClass.isInstance(listener)) { // null is not an instance of any class |
| throw new ClassCastException("listener " + listener + " is not " + |
| "an instance of listener class " + listenerClass); |
| } |
| |
| for (int i = 0; i < listenerList.length; i++) { |
| if (listenerList[i].equals(listener)) { |
| EventListener[] tmp = (EventListener[])Array.newInstance(listenerClass, |
| listenerList.length - 1); |
| System.arraycopy(listenerList, 0, tmp, 0, i); |
| System.arraycopy(listenerList, i + 1, tmp, i, listenerList.length - i - 1); |
| listenerList = tmp; |
| |
| return true; |
| } |
| } |
| |
| return false; |
| } |
| |
| /** |
| * Returns an array of all the listeners contained in this aggregate. |
| * The array is the data structure in which listeners are stored internally. |
| * The runtime type of the returned array is "array of <code>listenerClass</code>" |
| * (<code>listenerClass</code> has been specified as a parameter to |
| * the constructor of this class). |
| * |
| * @return all the listeners contained in this aggregate (an empty |
| * array if there are no listeners) |
| */ |
| public synchronized EventListener[] getListenersInternal() { |
| return listenerList; |
| } |
| |
| /** |
| * Returns an array of all the listeners contained in this aggregate. |
| * The array is a copy of the data structure in which listeners are stored |
| * internally. |
| * The runtime type of the returned array is "array of <code>listenerClass</code>" |
| * (<code>listenerClass</code> has been specified as a parameter to |
| * the constructor of this class). |
| * |
| * @return a copy of all the listeners contained in this aggregate (an empty |
| * array if there are no listeners) |
| */ |
| public synchronized EventListener[] getListenersCopy() { |
| return (listenerList.length == 0) ? listenerList : (EventListener[])listenerList.clone(); |
| } |
| |
| /** |
| * Returns the number of lisetners in this aggregate. |
| * |
| * @return the number of lisetners in this aggregate |
| */ |
| public synchronized int size() { |
| return listenerList.length; |
| } |
| |
| /** |
| * Returns <code>true</code> if this aggregate contains no listeners, |
| * <code>false</code> otherwise. |
| * |
| * @return <code>true</code> if this aggregate contains no listeners, |
| * <code>false</code> otherwise |
| */ |
| public synchronized boolean isEmpty() { |
| return listenerList.length == 0; |
| } |
| } |