Head First EJB

Writing a message-driven bean: your job as Bean Provider

You put THREE kinds of methods in the bean class:

1. Bean Law: ejbCreate() method

   Write a single, no-argument ejbCreate() method in the bean. It doesn’t match anything or come from any interface. It’s there because it MUST be.

2. MessageListener implementation: onMessage()

   This is your business method. Your only business method.

   <<interface>> MessageListener

   onMessage()

3. MessageDrivenBean implementation: container callbacks

   Implement both of the methods from the MessageDrivenBean interface, which your bean must implement in the official Java way (i.e. using the ‘implements MessageDrivenBean’ declaration either in your bean class or one of its superclasses)

   <<interface>> MessageDrivenBean

   ejbRemove() setMessageDrivenContext()

Sharpen your pencil

Compiler-checked?

Of the three types of methods you put in your bean, check off the ones the compiler cares about.

	ejbCreate()
	onMessage()
	ejbRemove() and setMessageDrivenContext()

Rules for the message-driven bean class

1. The class must implement javax.ejb.MessageDrivenBean and javax.jms.MessageListener.

   public class ...