Java Message Service Examples - The Java EE 6 Tutorial: Advanced Topics - page 439

The client then calls the bean's business method twice.
Coding the Publisher Session Bean
The Publisher bean is a stateless session bean that has one business method. The Publisher
bean uses a remote interface rather than a local interface because it is accessed from the
application client.
The remote interface, clientsessionmdb-ejb/src/java/sb/PublisherRe-
mote.java , declares a single business method, publishNews .
The bean class, clientsessionmdb-ejb/src/java/sb/Publisher-
Bean.java , implements the publishNews method and its helper method
chooseType . The bean class also injects SessionContext , ConnectionFact-
ory , and Topic resources and implements @PostConstruct and @PreDestroy
callback methods. The bean class begins as follows:
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@Stateless
@Remote({PublisherRemote.class})
public class PublisherBean implements PublisherRemote {
@Resource
private SessionContext sc;
@Resource(lookup = "jms/ConnectionFactory")
private ConnectionFactory connectionFactory;
@Resource(lookup = "jms/Topic")
private Topic topic;
...
The @PostConstruct callback method of the bean class, makeConnection , creates
the Connection used by the bean. The business method publishNews creates a
Session and a MessageProducer and publishes the messages.
The @PreDestroy callback method, endConnection , deallocates the resources that
were allocated by the @PostConstruct callback method. In this case, the method
closes the Connection .
Coding the Message-Driven Bean: MessageBean.java
The message-driven bean class, clientsessionmdb-ejb/src/java/mdb/Mes-
sageBean.java , is almost identical to the one in Chapter 11 , “ A Message-Driven