io.datalayer.activemq.consumer.ConsumerBean.java Source code

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Here is the source code for io.datalayer.activemq.consumer.ConsumerBean.java

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/****************************************************************
 * Licensed to the AOS Community (AOS) under one or more        *
 * contributor license agreements.  See the NOTICE file         *
 * distributed with this work for additional information        *
 * regarding copyright ownership.  The AOS 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.                                           *
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package io.datalayer.activemq.consumer;

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

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

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

public class ConsumerBean implements MessageListener {
    private static final Log LOG = LogFactory.getLog(ConsumerBean.class);
    private final List<Message> messages = new ArrayList<Message>();
    private boolean verbose;

    /**
     * Constructor.
     */
    public ConsumerBean() {
    }

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

    /**
     * Method implemented from MessageListener interface.
     *
     * @param message
     */
    public void onMessage(Message message) {
        synchronized (messages) {
            messages.add(message);
            if (verbose) {
                LOG.info("Received: " + message);
            }
            messages.notifyAll();
        }
    }

    /**
     * Use to wait for a single message to arrive.
     */
    public void waitForMessageToArrive() {
        LOG.info("Waiting for message to arrive");

        long start = System.currentTimeMillis();

        try {
            if (hasReceivedMessage()) {
                synchronized (messages) {
                    messages.wait(4000);
                }
            }
        } catch (InterruptedException e) {
            LOG.info("Caught: " + e);
        }
        long end = System.currentTimeMillis() - start;

        LOG.info("End of wait for " + end + " millis");
    }

    /**
     * Used to wait for a message to arrive given a particular message count.
     *
     * @param messageCount
     */
    public void waitForMessagesToArrive(int messageCount) {
        long maxRemainingMessageCount = Math.max(0, messageCount - messages.size());
        LOG.info("Waiting for (" + maxRemainingMessageCount + ") message(s) to arrive");
        long start = System.currentTimeMillis();
        long maxWaitTime = start + 120 * 1000;
        while (maxRemainingMessageCount > 0) {
            try {
                synchronized (messages) {
                    messages.wait(1000);
                }
                if (hasReceivedMessages(messageCount) || System.currentTimeMillis() > maxWaitTime) {
                    break;
                }
            } catch (InterruptedException e) {
                LOG.info("Caught: " + e);
            }
            maxRemainingMessageCount = Math.max(0, messageCount - messages.size());
        }
        long end = System.currentTimeMillis() - start;
        LOG.info("End of wait for " + end + " millis");
    }

    public void assertMessagesArrived(int total) {
        waitForMessagesToArrive(total);
        synchronized (messages) {
            int count = messages.size();

            assert (total == count);
        }
    }

    public boolean isVerbose() {
        return verbose;
    }

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

    /**
     * Identifies if the message is empty.
     *
     * @return
     */
    protected boolean hasReceivedMessage() {
        return messages.isEmpty();
    }

    /**
     * Identifies if the message count has reached the total size of message.
     *
     * @param messageCount
     * @return
     */
    protected boolean hasReceivedMessages(int messageCount) {
        synchronized (messages) {
            return messages.size() >= messageCount;
        }
    }
}