    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    }