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ActiveMQ example source code file (QueueBrowserSubscription.java)

This example ActiveMQ source code file (QueueBrowserSubscription.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

connectioncontext, exception, exception, invalidselectorexception, io, ioexception, ioexception, messageack, messageack, messageevaluationcontext, messagereference, queuebrowsersubscription, queuebrowsersubscription, queuesubscription, string

The ActiveMQ QueueBrowserSubscription.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 org.apache.activemq.broker.Broker;
import org.apache.activemq.broker.ConnectionContext;
import org.apache.activemq.command.ConsumerInfo;
import org.apache.activemq.command.MessageAck;
import org.apache.activemq.filter.MessageEvaluationContext;
import org.apache.activemq.usage.SystemUsage;

public class QueueBrowserSubscription extends QueueSubscription {

    int queueRefs;
    boolean browseDone;
    boolean destinationsAdded;

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

    protected boolean canDispatch(MessageReference node) {
        return !((QueueMessageReference)node).isAcked();
    }

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

    synchronized public void destinationsAdded() throws Exception {
        destinationsAdded = true;
        checkDone();
    }

    private void checkDone() throws Exception {
        if( !browseDone && queueRefs == 0 && destinationsAdded) {
            browseDone=true;
            add(QueueMessageReference.NULL_MESSAGE);
        }
    }

    public boolean matches(MessageReference node, MessageEvaluationContext context) throws IOException {
        return !browseDone && super.matches(node, context);
    }

    /**
     * Since we are a browser we don't really remove the message from the queue.
     */
    protected void acknowledge(ConnectionContext context, final MessageAck ack, final MessageReference n)
        throws IOException {
    	if (info.isNetworkSubscription()) {
    		super.acknowledge(context, ack, n);
    	}
    }

    synchronized public void incrementQueueRef() {
        queueRefs++;        
    }

    synchronized public void decrementQueueRef() throws Exception {
        queueRefs--;
        checkDone();
    }

}

Other ActiveMQ examples (source code examples)

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

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