Message Bean

This example illustrates how to use the Novell exteNd Messaging Platform message bean for simple create of message consumers. The MessageBean class extends the JMQMessageBean and only have to invoke to appropriate constructor and implement the onMessage method. The connection factory, connection, session and consumer objects are all available as bean properties in the JMQMessageBean superclass.

Below is the source code for the MessageBean class:

package bean;
                                                                           
import javax.naming.InitialContext;
                                                                           
import javax.jms.Queue;
import javax.jms.Message;
import javax.jms.TextMessage;
import javax.jms.JMSException;
import javax.jms.QueueConnectionFactory;
                                                                           
import com.sssw.jms.api.JMQMessageBean;
                                                                           
public class MessageBean extends JMQMessageBean
{
    public static void main(String[] args) throws Exception
    {
    |   // get the initial context
    |   InitialContext ctx = new InitialContext();
    |                                                                      
    |   // lookup the queue connection factory
    |   QueueConnectionFactory factory = (QueueConnectionFactory) ctx.
    |       lookup("queue/connectionFactory");
    |                                                                      
    |   // lookup the queue object
    |   Queue queue = (Queue) ctx.lookup("queue/queue0");
    |                                                                      
    |   // create bean and enter dispatch wait loop
    |   MessageBean bean = new MessageBean(factory, queue);
    |                                                                      
    |   System.out.println("bean ready to process messages ...");
    |                                                                      
    |   bean.run();
    }
                                                                           
    /**
       Simply calling the super class constructor connects this consumer.
       @param factory the queue connection factory
       @param queue the queue object
     */
    public MessageBean(QueueConnectionFactory factory, Queue queue)
        throws JMSException
    {
    |   super(factory, queue);
    }
                                                                           
    /**
       This method is called asynchronously by JMS when a message arrives
       at the queue.
       @param message A JMS message.
     */
    public void onMessage(Message message)
    {
    |   TextMessage msg = (TextMessage) message;
    |   try {
    |   |   System.out.println("received: " + msg.getText());
    |   } catch (JMSException ex) {
    |   |   ex.printStackTrace();
    |   }
    }
}

The MessageBean class simply invokes the constructor of the superclass with the connection factory and queue objects. The superclass creates the necessary connection, session and queue receiver objects and sets this class as the message listeners. As a result, the MessageBean class only has to implement the onMessage method. The run method can conveniently be used to suspend the calling thread.