001    /** 
002     * 
003     * Copyright 2004 Protique Ltd
004     * 
005     * Licensed under the Apache License, Version 2.0 (the "License"); 
006     * you may not use this file except in compliance with the License. 
007     * 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.activemq.transport;
019    import java.util.Iterator;
020    import EDU.oswego.cs.dl.util.concurrent.*;
021    import org.apache.commons.logging.Log;
022    import org.apache.commons.logging.LogFactory;
023    
024    /**
025     * A useful base class for {@link DiscoveryAgent} implementations
026     *
027     * @version $Revision: 1.1.1.1 $
028     */
029    public abstract class DiscoveryAgentSupport implements DiscoveryAgent {
030        private static final transient Log log = LogFactory.getLog(DiscoveryAgentSupport.class);
031    
032        protected CopyOnWriteArrayList listeners = new CopyOnWriteArrayList();
033    
034        /**
035         * Add a discovery listener
036         * @param listener
037         */
038        public void addDiscoveryListener(DiscoveryListener listener){
039            listeners.add(listener);
040        }
041        
042        /**
043         * remove a discovery listener
044         * @param listener
045         */
046        public void removeDiscoveryListener(DiscoveryListener listener){
047            listeners.remove(listener);
048        }
049    
050        protected void fireAddService(DiscoveryEvent event){
051            for(Iterator i = listeners.iterator(); i.hasNext();){
052                DiscoveryListener l = (DiscoveryListener)i.next();
053                if (log.isDebugEnabled()) {
054                    log.debug("on Add service: " + event);
055                }
056                l.addService(event);
057            }
058        }
059        
060        protected void fireRemoveService(DiscoveryEvent event){
061            for(Iterator i = listeners.iterator(); i.hasNext();){
062                DiscoveryListener l = (DiscoveryListener)i.next();
063                if (log.isDebugEnabled()) {
064                    log.debug("on Remove service: " + event);
065                }
066                l.removeService(event);
067            }
068        }
069    
070    }