moos.ssds.jms
Class SubscriberComponent

java.lang.Object
  moos.ssds.jms.SubscriberComponent

public class SubscriberComponent

extends java.lang.Object

SubscriberComponent provides an easy to use class that handles JMS publish-subscribe messaging. The goal of this is to povide messsaging without requiring the developer to use JMS api's

Here's an example of code using a SubscriberComponent

 import ssds.portal.*;

 public class Subscriber1 {

    SubscriberComponent sc;
    SensorDataPacketListener listener = new SensorDataPacketListener();

    public Subscriber1(String topicName) {
        sc = new SubscriberComponent(topicName, listener);
    }

    public static void main(String[] args) {
        try {
            Subscriber1 sub = new Subscriber1(args[0]);

        } catch (Throwable e) {
            e.printStackTrace();
        }
    }
 }

 

Note: I tried overriding the finalize() method to close the TopicConnection when the class was no longer used. However, the garbage collector would call the finalize() method at seemingly random times. Causing the program to cease. Moving the close() call out of the finalize() method stopeed this problem.

Version:

: $Revision: 1.2 $

The Monterey Bay Aquarium Research Institute (MBARI) provides this documentation and code "as is", with no warranty, express or implied, of its quality or consistency. It is provided without support and without obligation on the part of MBARI to assist in its use, correction, modification, or enhancement. This information should not be published or distributed to third parties without specific written permission from MBARI.

Copyright 2002 MBARI.
MBARI Proprietary Information. All rights reserved.

Author:

: $Author: kgomes $

Field Summary

protected javax.naming.Context	jndiContext This the the naming Context that will be used to look up the JMS related servcies.
protected javax.jms.Message	message A dummy message
protected javax.jms.TopicConnection	topicConnection This is the TopicConnection to the JMS server
protected javax.jms.TopicConnectionFactory	topicConnectionFactory This is the JMS TopicConnectionFactory that is used to get the topic connection for this subscriber
protected java.lang.String	topicname The topic name that this SubscriberComponent will subscribe to
protected javax.jms.TopicSession	topicSession This is the TopicSession that will be used to listen and process messages coming from JMS
protected javax.jms.TopicSubscriber	topicSubscriber This is the TopicSubscriber obtained from the JMS server

Constructor Summary

SubscriberComponent(java.lang.String topicName, javax.jms.MessageListener messageListener)
Constructor

Method Summary

void	close() Closes the topic connection.
javax.jms.MessageListener	getMessageListener() Accessor for the MessageListener
java.lang.String	getTopicname() Accessor for the topic name

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

topicname

protected java.lang.String topicname

The topic name that this SubscriberComponent will subscribe to

jndiContext

protected javax.naming.Context jndiContext

This the the naming Context that will be used to look up the JMS related servcies. It is going to use the first jndi.properties file it finds in its classpath to determine which JNDI service to utilize.

topicConnectionFactory

protected javax.jms.TopicConnectionFactory topicConnectionFactory

This is the JMS TopicConnectionFactory that is used to get the topic connection for this subscriber

topicSession

protected javax.jms.TopicSession topicSession

This is the TopicSession that will be used to listen and process messages coming from JMS

topicConnection

protected javax.jms.TopicConnection topicConnection

This is the TopicConnection to the JMS server

message

protected javax.jms.Message message

A dummy message

topicSubscriber

protected javax.jms.TopicSubscriber topicSubscriber

This is the TopicSubscriber obtained from the JMS server

Constructor Detail

SubscriberComponent

public SubscriberComponent(java.lang.String topicName,
                           javax.jms.MessageListener messageListener)

Constructor

Parameters:

topicName - The name of the topic to subscribe to. For JBoss this needs to be "topic/someTopic" whereas most other J2EE servers would use "someTopic"

messageListener - The MessageListener to be used to handle the message.

Method Detail

getMessageListener

public javax.jms.MessageListener getMessageListener()

Accessor for the MessageListener

Returns:

The class used to process the messages recieved by this SubscriberComponent

getTopicname

public java.lang.String getTopicname()

Accessor for the topic name

Returns:

The topic name that this SubscriberComponent is subscribed to.

close

public void close()

Closes the topic connection. Should be called when the class is no longer used.