ActiveMQ example source code file (DemandSubscription.java)

This example ActiveMQ source code file (DemandSubscription.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

atomicboolean, atomicboolean, atomicinteger, atomicinteger, consumerinfo, consumerinfo, copyonwritearrayset, demandsubscription, demandsubscription, interruptedexception, log, logger, set, threading, threads, util, waiting

The ActiveMQ DemandSubscription.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.network;

import java.util.Set;
import java.util.concurrent.CopyOnWriteArraySet;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicInteger;

import org.apache.activemq.command.ConsumerId;
import org.apache.activemq.command.ConsumerInfo;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Represents a network bridge interface
 * 
 * 
 */
public class DemandSubscription {
    private static final Logger LOG = LoggerFactory.getLogger(DemandSubscription.class);

    private final ConsumerInfo remoteInfo;
    private final ConsumerInfo localInfo;
    private Set<ConsumerId> remoteSubsIds = new CopyOnWriteArraySet();

    private AtomicInteger dispatched = new AtomicInteger(0);
    private AtomicBoolean activeWaiter = new AtomicBoolean();

    DemandSubscription(ConsumerInfo info) {
        remoteInfo = info;
        localInfo = info.copy();
        localInfo.setNetworkSubscription(true);
        remoteSubsIds.add(info.getConsumerId());
    }

    /**
     * Increment the consumers associated with this subscription
     * 
     * @param id
     * @return true if added
     */
    public boolean add(ConsumerId id) {
        return remoteSubsIds.add(id);
    }

    /**
     * Increment the consumers associated with this subscription
     * 
     * @param id
     * @return true if removed
     */
    public boolean remove(ConsumerId id) {
        return remoteSubsIds.remove(id);
    }

    /**
     * @return true if there are no interested consumers
     */
    public boolean isEmpty() {
        return remoteSubsIds.isEmpty();
    }

    /**
     * @return Returns the localInfo.
     */
    public ConsumerInfo getLocalInfo() {
        return localInfo;
    }

    /**
     * @return Returns the remoteInfo.
     */
    public ConsumerInfo getRemoteInfo() {
        return remoteInfo;
    }

    public void waitForCompletion() {
        if (dispatched.get() > 0) {
            if (LOG.isDebugEnabled()) {
                LOG.debug("Waiting for completion for sub: " + localInfo.getConsumerId() + ", dispatched: " + this.dispatched.get());
            }
            activeWaiter.set(true);
            if (dispatched.get() > 0) {
                synchronized (activeWaiter) {
                    try {
                        activeWaiter.wait();
                    } catch (InterruptedException ignored) {
                    }
                }
                if (this.dispatched.get() > 0) {
                    LOG.warn("demand sub interrupted or timedout while waiting for outstanding responses, expect potentially " + this.dispatched.get() + " duplicate deliveried");
                }
            }
        }
    }

    public void decrementOutstandingResponses() {
        if (dispatched.decrementAndGet() == 0 && activeWaiter.get()) {
            synchronized (activeWaiter) {
                activeWaiter.notifyAll();
            }
        }
    }

    public boolean incrementOutstandingResponses() {
        dispatched.incrementAndGet();
        if (activeWaiter.get()) {
            decrementOutstandingResponses();
            return false;
        }
        return true;
    }
}