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    package org.apache.activemq.broker.region.virtual;
018    
019    import java.util.ArrayList;
020    import java.util.Iterator;
021    import java.util.List;
022    import java.util.Set;
023    
024    import org.apache.activemq.broker.ProducerBrokerExchange;
025    import org.apache.activemq.broker.region.Destination;
026    import org.apache.activemq.broker.region.DestinationFilter;
027    import org.apache.activemq.broker.region.DestinationInterceptor;
028    import org.apache.activemq.command.Message;
029    import org.apache.activemq.filter.DestinationMap;
030    
031    /**
032     * Implements <a
033     * href="http://activemq.apache.org/virtual-destinations.html">Virtual Topics</a>.
034     * 
035     * @org.apache.xbean.XBean
036     * @version $Revision: 650143 $
037     */
038    public class VirtualDestinationInterceptor implements DestinationInterceptor {
039    
040        private DestinationMap destinationMap = new DestinationMap();
041        private VirtualDestination[] virtualDestinations;
042    
043        public synchronized Destination intercept(Destination destination) {
044            Set virtualDestinations = destinationMap.get(destination.getActiveMQDestination());
045            List<Destination> destinations = new ArrayList<Destination>();
046            for (Iterator iter = virtualDestinations.iterator(); iter.hasNext();) {
047                VirtualDestination virtualDestination = (VirtualDestination)iter.next();
048                Destination newNestination = virtualDestination.intercept(destination);
049                destinations.add(newNestination);
050            }
051            if (!destinations.isEmpty()) {
052                if (destinations.size() == 1) {
053                    return destinations.get(0);
054                } else {
055                    // should rarely be used but here just in case
056                    return createCompositeDestination(destination, destinations);
057                }
058            }
059            return destination;
060        }
061        
062    
063        public synchronized void remove(Destination destination) {     
064        }
065    
066        public VirtualDestination[] getVirtualDestinations() {
067            return virtualDestinations;
068        }
069    
070        public void setVirtualDestinations(VirtualDestination[] virtualDestinations) {
071            destinationMap = new DestinationMap();
072            this.virtualDestinations = virtualDestinations;
073            for (int i = 0; i < virtualDestinations.length; i++) {
074                VirtualDestination virtualDestination = virtualDestinations[i];
075                destinationMap.put(virtualDestination.getVirtualDestination(), virtualDestination);
076            }
077        }
078    
079        protected Destination createCompositeDestination(Destination destination, final List<Destination> destinations) {
080            return new DestinationFilter(destination) {
081                public void send(ProducerBrokerExchange context, Message messageSend) throws Exception {
082                    for (Iterator<Destination> iter = destinations.iterator(); iter.hasNext();) {
083                        Destination destination = iter.next();
084                        destination.send(context, messageSend);
085                    }
086                }
087            };
088        }
089    
090    }