basictopicsubscriber.java

21天学通java的示例程序源代码

package com.wrox.pubsub;

import javax.naming.*;
import javax.jms.*;

public class BasicTopicSubscriber
{
    protected TopicConnection _connection =null;
    protected TopicSession _session = null;
    protected TopicSubscriber _subscriber = null;
    protected String _jndiTopicName = null;
    protected String _jndiTopicFactoryName = null;
    public BasicTopicSubscriber (String jndiTopicFactoryName, String jndiTopicName) throws NamingException, JMSException
    {
        super();
        _jndiTopicName = jndiTopicName;
        _jndiTopicFactoryName = jndiTopicFactoryName;
        initialize ();
    }
    protected void initialize () throws NamingException, JMSException
    {
        Context ctx = new InitialContext ();
        TopicConnectionFactory topicConnectionFactory =
        (TopicConnectionFactory) ctx.lookup (_jndiTopicFactoryName);
        Topic topic = (Topic) ctx.lookup (_jndiTopicName);
        _connection = topicConnectionFactory.createTopicConnection ();
        _session = _connection.createTopicSession (false, Session.AUTO_ACKNOWLEDGE);
        _subscriber = _session.createSubscriber (topic);
    }
    public void subscribe(MessageListener messageListener) throws JMSException
    {
        _connection.stop ();
        _subscriber.setMessageListener (messageListener);
        _connection.start ();
    }
    public void finalize ()
    {
        try
        {
            cleanup ();
        }
        catch(JMSException jmsEx)
        {
            // ignore this error
        }        
    }
    public void cleanup () throws JMSException
    {
        if(_connection != null)
        {
            _connection.close ();
        }
    }
}