cern.cmw.mom.pubsub

Interface Subscriber

All Known Implementing Classes:

DefaultSubscriberImpl

public interface Subscriber

Public interface. Provide topic subscription facilities.

Two kinds of exception are thrown :

• javax.jms.JMSException are thrown for exceptions caused by a problem in the underlying implementation.
• javax.naming.NamingException are thrown if the topic usage is not correct. Each time a topic is used, either in publication or in subscription, the topic name is checked against a topic namespace, to avoid namespace pollution and performance degradation.

This example shows a simple subscription to a topic:

 try {
   s = PubSubFactory.subscriber();
 } catch (MOMException momEx) { ... }
 try {
   subToken = s.subscribe("CMW.DEVICES.PowerConverter.PC1.Current", listener, selector);
   // ...
   s.unSubscribe(subToken);
   s.close();
 }
 catch (JMSException jmsEx) { ... }
 catch (NamingException namingEx) { ... }
 

where listener is an instance of a class implementing the SubscriptionListener interface method void onMessage(Message m) and selector is an optional String defining a message selector.

Author:

Controls Middleware Project

See Also:

Publisher, SubscriptionListener, PubSubFactory, NotificationHelper, MappingService

Method Summary

Modifier and Type	Method and Description
void	close() Close the publisher singleton instance and dealloacate any resource.
void	setExceptionListener(ExceptionListener listener) Set the listener for exceptions handling
long	subscribe(java.lang.String topic, SubscriptionListener listener, java.lang.String selector) Subscribe to the given topic.
void	unSubscribe(long subscriptionToken) Close the subscription identified by the subscriptionToken.
void	unSubscribeAll() Close all the opened subscriptions.

Method Detail

setExceptionListener

void setExceptionListener(ExceptionListener listener)

Set the listener for exceptions handling

Parameters:

listener - The exceptions listener

close

void close()

Close the publisher singleton instance and dealloacate any resource.

subscribe

long subscribe(java.lang.String topic,
               SubscriptionListener listener,
               java.lang.String selector)
        throws JMSException,
               javax.naming.NamingException

Subscribe to the given topic.

Parameters:

topic - The String representation of the topic

listener - An instance of a class implementing the SubscriptionListener interface

selector - The String representation of the filter. May be null.

Returns:

long the unique subscription token.

Throws:

JMSException - if JMS fails to subscribe due to some internal JMS error.

javax.naming.NamingException - if there is a violation in the namespace policy.

unSubscribe

void unSubscribe(long subscriptionToken)
          throws JMSException

Close the subscription identified by the subscriptionToken.

Parameters:

subscriptionToken - The subscription identifier

Throws:

JMSException - if JMS fails to unsubscribe due to some internal JMS error.

unSubscribeAll

void unSubscribeAll()
             throws JMSException

Close all the opened subscriptions.

Throws:

JMSException - if JMS fails to unsubscribe due to some internal JMS error.