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.Broker;
025    import org.apache.activemq.broker.ConnectionContext;
026    import org.apache.activemq.broker.ProducerBrokerExchange;
027    import org.apache.activemq.broker.region.Destination;
028    import org.apache.activemq.broker.region.DestinationFilter;
029    import org.apache.activemq.broker.region.DestinationInterceptor;
030    import org.apache.activemq.command.ActiveMQDestination;
031    import org.apache.activemq.command.Message;
032    import org.apache.activemq.filter.DestinationMap;
033    
034    /**
035     * Implements <a
036     * href="http://activemq.apache.org/virtual-destinations.html">Virtual Topics</a>.
037     * 
038     * @org.apache.xbean.XBean
039     * 
040     */
041    public class VirtualDestinationInterceptor implements DestinationInterceptor {
042    
043        private DestinationMap destinationMap = new DestinationMap();
044        private VirtualDestination[] virtualDestinations;
045    
046        public Destination intercept(Destination destination) {
047            Set matchingDestinations = destinationMap.get(destination.getActiveMQDestination());
048            List<Destination> destinations = new ArrayList<Destination>();
049            for (Iterator iter = matchingDestinations.iterator(); iter.hasNext();) {
050                VirtualDestination virtualDestination = (VirtualDestination)iter.next();
051                Destination newDestination = virtualDestination.intercept(destination);
052                destinations.add(newDestination);
053            }
054            if (!destinations.isEmpty()) {
055                if (destinations.size() == 1) {
056                    return destinations.get(0);
057                } else {
058                    // should rarely be used but here just in case
059                    return createCompositeDestination(destination, destinations);
060                }
061            }
062            return destination;
063        }
064        
065    
066        public synchronized void create(Broker broker, ConnectionContext context, ActiveMQDestination destination) throws Exception {
067            for (VirtualDestination virt: virtualDestinations) {
068                virt.create(broker, context, destination);
069            }
070        }
071    
072        public synchronized void remove(Destination destination) {     
073        }
074    
075        public VirtualDestination[] getVirtualDestinations() {
076            return virtualDestinations;
077        }
078    
079        public void setVirtualDestinations(VirtualDestination[] virtualDestinations) {
080            destinationMap = new DestinationMap();
081            this.virtualDestinations = virtualDestinations;
082            for (int i = 0; i < virtualDestinations.length; i++) {
083                VirtualDestination virtualDestination = virtualDestinations[i];
084                destinationMap.put(virtualDestination.getVirtualDestination(), virtualDestination);
085            }
086        }
087    
088        protected Destination createCompositeDestination(Destination destination, final List<Destination> destinations) {
089            return new DestinationFilter(destination) {
090                public void send(ProducerBrokerExchange context, Message messageSend) throws Exception {
091                    for (Iterator<Destination> iter = destinations.iterator(); iter.hasNext();) {
092                        Destination destination = iter.next();
093                        destination.send(context, messageSend);
094                    }
095                }
096            };
097        }
098    
099    }