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         * @return an {@link Iterator} for the {@link EventListener} instances
058         * @since 2.0
059         * TODO Check that this is a good defensive strategy
060         */
061        public Iterator<EventListener> iterator() {
062                return __listeners.iterator();
063        }
064    
065    }