trunk/activemq-core/src/main/java/org/apache/activemq/network/DurableConduitBridge.java

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.activemq.network;

import java.io.IOException;
import java.util.Iterator;

import org.apache.activemq.command.ActiveMQDestination;
import org.apache.activemq.command.ConsumerId;
import org.apache.activemq.command.ConsumerInfo;
import org.apache.activemq.filter.DestinationFilter;
import org.apache.activemq.transport.Transport;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Consolidates subscriptions
 * 
 * 
 */
public class DurableConduitBridge extends ConduitBridge {
    private static final Logger LOG = LoggerFactory.getLogger(DurableConduitBridge.class);

    /**
     * Constructor
     * 
     * @param configuration
     * 
     * @param localBroker
     * @param remoteBroker
     */
    public DurableConduitBridge(NetworkBridgeConfiguration configuration, Transport localBroker,
                                Transport remoteBroker) {
        super(configuration, localBroker, remoteBroker);
    }

    /**
     * Subscriptions for these destinations are always created
     * 
     */
    protected void setupStaticDestinations() {
        super.setupStaticDestinations();
        ActiveMQDestination[] dests = configuration.isDynamicOnly() ? null : durableDestinations;
        if (dests != null) {
            for (int i = 0; i < dests.length; i++) {
                ActiveMQDestination dest = dests[i];
                if (isPermissableDestination(dest) && !doesConsumerExist(dest)) {
                    DemandSubscription sub = createDemandSubscription(dest);
                    if (dest.isTopic()) {
                        sub.getLocalInfo().setSubscriptionName(getSubscriberName(dest));
                    }
                    try {
                        addSubscription(sub);
                    } catch (IOException e) {
                        LOG.error("Failed to add static destination " + dest, e);
                    }
                    if (LOG.isTraceEnabled()) {
                        LOG.trace("Forwarding messages for durable destination: " + dest);
                    }
                }
            }
        }
    }

    protected DemandSubscription createDemandSubscription(ConsumerInfo info) throws IOException {
        if (addToAlreadyInterestedConsumers(info)) {
            return null; // don't want this subscription added
        }
        //add our original id to ourselves
        info.addNetworkConsumerId(info.getConsumerId());

        if (info.isDurable()) {
            // set the subscriber name to something reproducible
            info.setSubscriptionName(getSubscriberName(info.getDestination()));
            // and override the consumerId with something unique so that it won't
            // be removed if the durable subscriber (at the other end) goes away
            info.setConsumerId(new ConsumerId(localSessionInfo.getSessionId(), consumerIdGenerator
                    .getNextSequenceId()));
        }
        info.setSelector(null);
        return doCreateDemandSubscription(info);
    }

    protected String getSubscriberName(ActiveMQDestination dest) {
        String subscriberName = DURABLE_SUB_PREFIX + configuration.getBrokerName() + "_" + dest.getPhysicalName();
        return subscriberName;
    }

    protected boolean doesConsumerExist(ActiveMQDestination dest) {
        DestinationFilter filter = DestinationFilter.parseFilter(dest);
        for (Iterator i = subscriptionMapByLocalId.values().iterator(); i.hasNext();) {
            DemandSubscription ds = (DemandSubscription)i.next();
            if (filter.matches(ds.getLocalInfo().getDestination())) {
                return true;
            }
        }
        return false;
    }
}