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
018package org.apache.commons.net.util;
019
020import java.io.Serializable;
021import java.util.EventListener;
022import java.util.Iterator;
023import java.util.concurrent.CopyOnWriteArrayList;
024
025/**
026 * @author Daniel F. Savarese
027 */
028
029public class ListenerList implements Serializable, Iterable<EventListener>
030{
031    private final CopyOnWriteArrayList<EventListener> __listeners;
032
033    public ListenerList()
034    {
035        __listeners = new CopyOnWriteArrayList<EventListener>();
036    }
037
038    public void addListener(EventListener listener)
039    {
040            __listeners.add(listener);
041    }
042
043    public  void removeListener(EventListener listener)
044    {
045            __listeners.remove(listener);
046    }
047
048    public int getListenerCount()
049    {
050        return __listeners.size();
051    }
052    
053    /**
054     * Return an {@link Iterator} for the {@link EventListener} instances
055     * 
056     * @since 2.0
057     * TODO Check that this is a good defensive strategy
058     */
059    public Iterator<EventListener> iterator() {
060            return __listeners.iterator();
061    }
062
063}