001 /* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 018 package org.apache.commons.net.util; 019 020 import java.io.Serializable; 021 import java.util.EventListener; 022 import java.util.Iterator; 023 import java.util.concurrent.CopyOnWriteArrayList; 024 025 /** 026 */ 027 028 public class ListenerList implements Serializable, Iterable<EventListener> 029 { 030 private static final long serialVersionUID = -1934227607974228213L; 031 032 private final CopyOnWriteArrayList<EventListener> __listeners; 033 034 public ListenerList() 035 { 036 __listeners = new CopyOnWriteArrayList<EventListener>(); 037 } 038 039 public void addListener(EventListener listener) 040 { 041 __listeners.add(listener); 042 } 043 044 public void removeListener(EventListener listener) 045 { 046 __listeners.remove(listener); 047 } 048 049 public int getListenerCount() 050 { 051 return __listeners.size(); 052 } 053 054 /** 055 * Return an {@link Iterator} for the {@link EventListener} instances 056 * 057 * @since 2.0 058 * TODO Check that this is a good defensive strategy 059 */ 060 public Iterator<EventListener> iterator() { 061 return __listeners.iterator(); 062 } 063 064 }