Enterprise JavaBeans 3.1, 6th Edition

Defining a Web Service with JAX-RPC

Java EE provides two different programming models for defining a JAX-RPC web service: the web container model (or servlet model) and the EJB container model. Given that this book is about EJB 3.1, we assume you are more interested in the EJB model.

The core component in the EJB model is called an EJB endpoint. An EJB endpoint is a stateless session bean that is exposed as a web service. In addition to the remote and local component interfaces, there is another component interface, called the service endpoint interface. The service endpoint interface defines the abstract web services contract that the EJB endpoint provides to a web services client.

Because an EJB endpoint is simply a SOAP-accessible stateless session bean, it has the same advantages as other EJBs. An EJB endpoint runs in the same EJB container that automatically manages transactions and security, and provides access to other EJBs and resources via injection or the JNDI ENC.

The WSDL Document

Every EJB endpoint must have a WSDL document that describes the web service. You can create this document by hand, or you can use the tools provided by your Java EE vendor to generate it. The <portType> declared by the WSDL document must be aligned with the endpoint interface of the web service. In other words, the mapping between the WSDL <portType> and the endpoint interface must be correct according to the JAX-RPC specification. One way to ensure this is to create the WSDL document first, and ...