The Java EE 5 Tutorial

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/, declares a single business method, publishNews.

The bean class, clientsessionmdb-ejb/src/java/sb/, implements the publishNews method and its helper method chooseType. The bean class also injects SessionContext, ConnectionFactory, and Topic resources and implements @PostConstruct and @PreDestroy callback methods. The bean class begins as follows:

public class PublisherBean implements PublisherRemote {

    private SessionContext sc;

    private ConnectionFactory connectionFactory;

    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.