ChatController.java

/*
 * Created by Andrea Vida
 * University of Parma (Italy)
 * 
 */
package net.blogracy.controller;

import javax.jms.Connection;
import javax.jms.ConnectionFactory;
import javax.jms.DeliveryMode;
import javax.jms.Destination;
import javax.jms.JMSException;
import javax.jms.MessageProducer;
import javax.jms.Session;
import javax.jms.TextMessage;

import org.apache.activemq.ActiveMQConnection;
import org.apache.activemq.ActiveMQConnectionFactory;

public class ChatController {

    private ConnectionFactory connectionFactory;
    private Connection connection;
    private Session session;
    private Destination topic;
    private MessageProducer producer;
    private static final String TOPIC_NAME = "CHAT.DEMO";

    private String localUser;
    private String remoteUser;

    private static final ChatController theInstance = new ChatController();

    public static ChatController getSingleton() {
        return theInstance;
    }

    public ChatController() {
        try {
            connectionFactory = new ActiveMQConnectionFactory(
                    ActiveMQConnection.DEFAULT_BROKER_URL);
            connection = connectionFactory.createConnection();
            connection.start();

            session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
            topic = session.createTopic(TOPIC_NAME);
            producer = session.createProducer(topic);
            producer.setDeliveryMode(DeliveryMode.NON_PERSISTENT);
        } catch (Exception e) {
            System.out.println("JMS error: creating the text listener");
        }
    }

    public void joinChannel(String channel) {
        System.out.println("Creating chat channel: " + channel);
        try {
            TextMessage msg = session.createTextMessage();
            msg.setText("<message type=\"join\" from=\"" + localUser
                    + "\" channel=\"" + channel + "\"/>");
            producer.send(topic, msg);
        } catch (JMSException e) {
            System.out.println("JMS error: join channel");
        }
    }

    public void sendMessage(String channel, String text) {
        System.out.println("Creating chat channel: " + channel);
        try {
            TextMessage msg = session.createTextMessage();
            msg.setText("<message type=\"chat\" from=\"" + localUser
                    + "\" channel=\"" + channel + "\">" + text + "</message>");
            producer.send(topic, msg);
        } catch (JMSException e) {
            System.out.println("JMS error: send message");
        }
    }

    public static String getPrivateChannel(String localUser, String remoteUser) {
        if (localUser.compareTo(remoteUser) <= 0) {
            return localUser + remoteUser;
        }
        return remoteUser + localUser;
    }
}