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 */
017package org.apache.activemq.broker.region.virtual;
018
019import java.util.ArrayList;
020import java.util.Arrays;
021import java.util.Iterator;
022import java.util.List;
023import java.util.Set;
024
025import org.apache.activemq.broker.Broker;
026import org.apache.activemq.broker.ConnectionContext;
027import org.apache.activemq.broker.ProducerBrokerExchange;
028import org.apache.activemq.broker.region.Destination;
029import org.apache.activemq.broker.region.DestinationFilter;
030import org.apache.activemq.broker.region.DestinationInterceptor;
031import org.apache.activemq.command.ActiveMQDestination;
032import org.apache.activemq.command.Message;
033import org.apache.activemq.filter.DestinationMap;
034
035/**
036 * Implements <a
037 * href="http://activemq.apache.org/virtual-destinations.html">Virtual
038 * Topics</a>.
039 *
040 * @org.apache.xbean.XBean
041 *
042 */
043public class VirtualDestinationInterceptor implements DestinationInterceptor {
044
045    private DestinationMap destinationMap = new DestinationMap();
046    private DestinationMap mappedDestinationMap = new DestinationMap();
047
048    private VirtualDestination[] virtualDestinations;
049
050    @Override
051    public Destination intercept(Destination destination) {
052        final ActiveMQDestination activeMQDestination = destination.getActiveMQDestination();
053        Set matchingDestinations = destinationMap.get(activeMQDestination);
054        List<Destination> destinations = new ArrayList<Destination>();
055        for (Iterator iter = matchingDestinations.iterator(); iter.hasNext();) {
056            VirtualDestination virtualDestination = (VirtualDestination) iter.next();
057            Destination newDestination = virtualDestination.intercept(destination);
058            destinations.add(newDestination);
059        }
060        if (!destinations.isEmpty()) {
061            if (destinations.size() == 1) {
062                return destinations.get(0);
063            } else {
064                // should rarely be used but here just in case
065                return createCompositeDestination(destination, destinations);
066            }
067        }
068        // check if the destination instead matches any mapped destinations
069        Set mappedDestinations = mappedDestinationMap.get(activeMQDestination);
070        assert mappedDestinations.size() < 2;
071        if (!mappedDestinations.isEmpty()) {
072            // create a mapped destination interceptor
073            VirtualDestination virtualDestination = (VirtualDestination)
074                mappedDestinations.toArray(new VirtualDestination[mappedDestinations.size()])[0];
075            return virtualDestination.interceptMappedDestination(destination);
076        }
077
078        return destination;
079    }
080
081    @Override
082    public synchronized void create(Broker broker, ConnectionContext context, ActiveMQDestination destination) throws Exception {
083        for (VirtualDestination virt : virtualDestinations) {
084            virt.create(broker, context, destination);
085        }
086    }
087
088    @Override
089    public synchronized void remove(Destination destination) {
090    }
091
092    public VirtualDestination[] getVirtualDestinations() {
093        return virtualDestinations;
094    }
095
096    public void setVirtualDestinations(VirtualDestination[] virtualDestinations) {
097        destinationMap = new DestinationMap();
098        mappedDestinationMap = new DestinationMap();
099        this.virtualDestinations = virtualDestinations;
100        for (int i = 0; i < virtualDestinations.length; i++) {
101            VirtualDestination virtualDestination = virtualDestinations[i];
102            destinationMap.put(virtualDestination.getVirtualDestination(), virtualDestination);
103            mappedDestinationMap.put(virtualDestination.getMappedDestinations(), virtualDestination);
104        }
105    }
106
107    protected Destination createCompositeDestination(Destination destination, final List<Destination> destinations) {
108        return new DestinationFilter(destination) {
109            @Override
110            public void send(ProducerBrokerExchange context, Message messageSend) throws Exception {
111                for (Iterator<Destination> iter = destinations.iterator(); iter.hasNext();) {
112                    Destination destination = iter.next();
113                    destination.send(context, messageSend);
114                }
115            }
116        };
117    }
118
119    @Override
120    public String toString() {
121        return "VirtualDestinationInterceptor" + Arrays.asList(virtualDestinations);
122    }
123}