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ActiveMQ example source code file (QueueSubscription.java)

This example ActiveMQ source code file (QueueSubscription.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - ActiveMQ tags/keywords

activemqmessage, activemqmessage, connectioncontext, io, ioexception, ioexception, jmsxgroupfirstforconsumer, messageack, messagereference, queue, queuemessagereference, queuemessagereference, queuesubscription, queuesubscription, string

The ActiveMQ QueueSubscription.java source code

/**
 * 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.broker.region;

import java.io.IOException;
import javax.jms.InvalidSelectorException;
import javax.jms.JMSException;
import org.apache.activemq.broker.Broker;
import org.apache.activemq.broker.ConnectionContext;
import org.apache.activemq.broker.region.group.MessageGroupMap;
import org.apache.activemq.command.ActiveMQMessage;
import org.apache.activemq.command.ConsumerInfo;
import org.apache.activemq.command.Message;
import org.apache.activemq.command.MessageAck;
import org.apache.activemq.usage.SystemUsage;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class QueueSubscription extends PrefetchSubscription implements LockOwner {

    private static final Logger LOG = LoggerFactory.getLogger(QueueSubscription.class);

    public QueueSubscription(Broker broker, SystemUsage usageManager, ConnectionContext context, ConsumerInfo info) throws InvalidSelectorException {
        super(broker,usageManager, context, info);
    }

    /**
     * In the queue case, mark the node as dropped and then a gc cycle will
     * remove it from the queue.
     * 
     * @throws IOException
     */
    protected void acknowledge(final ConnectionContext context, final MessageAck ack, final MessageReference n) throws IOException {
        final Destination q = n.getRegionDestination();
        final QueueMessageReference node = (QueueMessageReference)n;
        final Queue queue = (Queue)q;
        
        if (n.isExpired()) {
            // sync with message expiry processing
            if (!broker.isExpired(n)) {
                LOG.warn("ignoring ack " + ack + ", for already expired message: " + n);
                return;
            }
        }
        queue.removeMessage(context, this, node, ack);
    }

    protected boolean canDispatch(MessageReference n) throws IOException {
        boolean result = true;
        QueueMessageReference node = (QueueMessageReference)n;
        if (node.isAcked() || node.isDropped()) {
            result = false;
        }
        result = result && (isBrowser() || node.lock(this));
        return result;
    }

    /**
     * Assigns the message group to this subscription and set the flag on the
     * message that it is the first message to be dispatched.
     */
    protected void assignGroupToMe(MessageGroupMap messageGroupOwners, MessageReference n, String groupId) throws IOException {
        messageGroupOwners.put(groupId, info.getConsumerId());
        Message message = n.getMessage();
        if (message instanceof ActiveMQMessage) {
            ActiveMQMessage activeMessage = (ActiveMQMessage)message;
            try {
                activeMessage.setBooleanProperty("JMSXGroupFirstForConsumer", true, false);
            } catch (JMSException e) {
                LOG.warn("Failed to set boolean header: " + e, e);
            }
        }
    }

    public synchronized String toString() {
        return "QueueSubscription:" + " consumer=" + info.getConsumerId() + ", destinations=" + destinations.size() + ", dispatched=" + dispatched.size() + ", delivered="
               + this.prefetchExtension + ", pending=" + getPendingQueueSize();
    }

    public int getLockPriority() {
        return info.getPriority();
    }

    public boolean isLockExclusive() {
        return info.isExclusive();
    }

    /**
     */
    public void destroy() {
        setSlowConsumer(false);
    }

   
    protected boolean isDropped(MessageReference node) {
       boolean result = false;
       if(node instanceof IndirectMessageReference) {
           QueueMessageReference qmr = (QueueMessageReference) node;
           result = qmr.isDropped();
       }
       return result;
    }

}

Other ActiveMQ examples (source code examples)

Here is a short list of links related to this ActiveMQ QueueSubscription.java source code file:

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