ActiveMQ example source code file (MemMessageIdList.java)

This example ActiveMQ source code file (MemMessageIdList.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

arraylist, arraylist, jmsexception, list, list, logger, memmessageidlist, memmessageidlist, messagelistener, messagelistener, object, received, string, util, waiting

The ActiveMQ MemMessageIdList.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.tool;

import java.util.ArrayList;
import java.util.List;

import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.MessageListener;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * A simple container of messages for performing testing and rendezvous style
 * code. You can use this class a {@link MessageListener} and then make
 * assertions about how many messages it has received allowing a certain maximum
 * amount of time to ensure that the test does not hang forever.
 * <p/>
 * Also you can chain these instances together with the
 * {@link #setParent(MessageListener)} method so that you can aggregate the
 * total number of messages consumed across a number of consumers.
 *
 * 
 */
public class MemMessageIdList implements MessageListener {

    protected static final Logger LOG = LoggerFactory.getLogger(MemMessageIdList.class);

    private List<String> messageIds = new ArrayList();
    private Object semaphore;
    private boolean verbose;
    private MessageListener parent;
    private long maximumDuration = 15000L;

    public MemMessageIdList() {
        this(new Object());
    }

    public MemMessageIdList(Object semaphore) {
        this.semaphore = semaphore;
    }

    public boolean equals(Object that) {
        if (that instanceof MemMessageIdList) {
            MemMessageIdList thatListMem = (MemMessageIdList) that;
            return getMessageIds().equals(thatListMem.getMessageIds());
        }
        return false;
    }

    public int hashCode() {
        synchronized (semaphore) {
            return messageIds.hashCode() + 1;
        }
    }

    public String toString() {
        synchronized (semaphore) {
            return messageIds.toString();
        }
    }

    /**
     * @return all the messages on the list so far, clearing the buffer
     */
    public List<String> flushMessages() {
        synchronized (semaphore) {
            List<String> answer = new ArrayList(messageIds);
            messageIds.clear();
            return answer;
        }
    }

    public synchronized List<String> getMessageIds() {
        synchronized (semaphore) {
            return new ArrayList<String>(messageIds);
        }
    }

    public void onMessage(Message message) {
        String id = null;
        try {
            id = message.getJMSMessageID();
            synchronized (semaphore) {
                messageIds.add(id);
                semaphore.notifyAll();
            }
            if (verbose) {
                LOG.info("Received message: " + message);
            }
        } catch (JMSException e) {
            e.printStackTrace();
        }
        if (parent != null) {
            parent.onMessage(message);
        }
    }

    public int getMessageCount() {
        synchronized (semaphore) {
            return messageIds.size();
        }
    }

    public void waitForMessagesToArrive(int messageCount) {
        LOG.info("Waiting for " + messageCount + " message(s) to arrive");

        long start = System.currentTimeMillis();

        for (int i = 0; i < messageCount; i++) {
            try {
                if (hasReceivedMessages(messageCount)) {
                    break;
                }
                long duration = System.currentTimeMillis() - start;
                if (duration >= maximumDuration) {
                    break;
                }
                synchronized (semaphore) {
                    semaphore.wait(maximumDuration - duration);
                }
            } catch (InterruptedException e) {
                LOG.info("Caught: " + e);
            }
        }
        long end = System.currentTimeMillis() - start;

        LOG.info("End of wait for " + end + " millis and received: " + getMessageCount() + " messages");
    }


    public boolean hasReceivedMessage() {
        return getMessageCount() == 0;
    }

    public boolean hasReceivedMessages(int messageCount) {
        return getMessageCount() >= messageCount;
    }

    public boolean isVerbose() {
        return verbose;
    }

    public void setVerbose(boolean verbose) {
        this.verbose = verbose;
    }

    public MessageListener getParent() {
        return parent;
    }

    /**
     * Allows a parent listener to be specified such as to aggregate messages
     * consumed across consumers
     */
    public void setParent(MessageListener parent) {
        this.parent = parent;
    }

}