org.dawnsci.commandserver.core.producer.Broadcaster.java Source code

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Here is the source code for org.dawnsci.commandserver.core.producer.Broadcaster.java

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/*
 * Copyright (c) 2012 Diamond Light Source Ltd.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 */
package org.dawnsci.commandserver.core.producer;

import java.io.PrintStream;
import java.net.URI;
import java.util.Enumeration;

import javax.jms.DeliveryMode;
import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.MessageConsumer;
import javax.jms.MessageProducer;
import javax.jms.Queue;
import javax.jms.QueueBrowser;
import javax.jms.QueueConnection;
import javax.jms.QueueConnectionFactory;
import javax.jms.QueueSession;
import javax.jms.Session;
import javax.jms.TextMessage;
import javax.jms.Topic;

import org.dawnsci.commandserver.core.ConnectionFactoryFacade;
import org.dawnsci.commandserver.core.beans.StatusBean;
import org.dawnsci.commandserver.core.consumer.RemoteSubmission;

import com.fasterxml.jackson.databind.ObjectMapper;

/**
 * Class which can broadcast a status bean to a queue and a topic
 * when the broadcast method is called.
 * 
 * @author Matthew Gerring
 *
 */
public class Broadcaster {

    private final URI uri;
    private final String queueName;
    private final String topicName;

    private PrintStream out = System.out;

    public Broadcaster(URI uri, String queueName, String topicName) {
        this.uri = uri;
        this.queueName = queueName;
        this.topicName = topicName;
    }

    /**
     * Notify any clients of the beans status
     * @param bean
     * @param add true to add a new message, false to find and update and old one.
     */
    public void broadcast(StatusBean bean, boolean add) throws Exception {

        if (connection == null)
            createConnection();
        if (add) {
            addQueue(bean);
        } else {
            updateQueue(bean); // For clients connecting in future or after a refresh - persistence.
        }

        final ObjectMapper mapper = new ObjectMapper();

        // Here we are sending the message out to the topic
        TextMessage temp = session.createTextMessage(mapper.writeValueAsString(bean));
        topicProducer.send(temp, DeliveryMode.NON_PERSISTENT, 1, 5000);

        if (out != null) {
            out.println(bean.toString());
            out.flush();
        }

        if (bean.getStatus().isFinal()) { // No more updates!
            dispose();
        }

    }

    private QueueConnection connection;
    private QueueSession qSes;
    private Queue queue;
    private MessageProducer topicProducer;
    private Session session;

    public void dispose() throws JMSException {
        try {
            if (out != null && out != System.out) {
                out.close();
                out = null;
            }

            qSes.close();
            session.close();
            connection.close();

        } finally {
            connection = null;
            qSes = null;
            queue = null;
            topicProducer = null;
            session = null;
        }
    }

    /**
     * 
     * @param bean
     * @throws Exception 
     */
    private void addQueue(StatusBean bean) throws Exception {

        RemoteSubmission factory = new RemoteSubmission(uri);
        factory.setQueueName(queueName); // Move the message over to a status queue.

        factory.submit(bean, false);

    }

    private void createConnection() throws Exception {

        QueueConnectionFactory connectionFactory = ConnectionFactoryFacade.createConnectionFactory(uri);
        this.connection = connectionFactory.createQueueConnection();
        this.qSes = connection.createQueueSession(false, Session.AUTO_ACKNOWLEDGE);
        this.queue = qSes.createQueue(queueName);

        this.session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
        final Topic topic = session.createTopic(topicName);
        this.topicProducer = session.createProducer(topic);

        connection.start();

    }

    /**
     * 
     * @param bean
     * @throws Exception 
     */
    private void updateQueue(StatusBean bean) throws Exception {

        QueueConnection qCon = null;

        try {

            QueueBrowser qb = qSes.createBrowser(queue);

            @SuppressWarnings("rawtypes")
            Enumeration e = qb.getEnumeration();

            ObjectMapper mapper = new ObjectMapper();
            String jMSMessageID = null;
            while (e.hasMoreElements()) {
                Message m = (Message) e.nextElement();
                if (m == null)
                    continue;
                if (m instanceof TextMessage) {
                    TextMessage t = (TextMessage) m;

                    @SuppressWarnings("unchecked")
                    final StatusBean qbean = mapper.readValue(t.getText(), bean.getClass());
                    if (qbean == null)
                        continue;
                    if (qbean.getUniqueId() == null)
                        continue; // Definitely not our bean
                    if (qbean.getUniqueId().equals(bean.getUniqueId())) {
                        jMSMessageID = t.getJMSMessageID();
                        break;
                    }
                }
            }

            qb.close();

            if (jMSMessageID != null) {
                MessageConsumer consumer = qSes.createConsumer(queue, "JMSMessageID = '" + jMSMessageID + "'");
                Message m = consumer.receive(1000);
                if (m != null && m instanceof TextMessage) {
                    MessageProducer producer = qSes.createProducer(queue);
                    producer.send(qSes.createTextMessage(mapper.writeValueAsString(bean)));
                }
            }
        } finally {
            if (qCon != null)
                qCon.close();
        }

    }

    public URI getUri() {
        return uri;
    }

    public String getQueueName() {
        return queueName;
    }

    public String getTopicName() {
        return topicName;
    }

    public void setLoggingStream(PrintStream out) {
        this.out = out;
    }

}