iSeries Access for Web V5R2 and WebSphere Host Publisher V4.0

Chapter 6. Using Host Publisher Studio to develop J2EE applications 207

6.7 Enterprise JavaBeans support

Enterprise JavaBeans is a server-side component architecture that enables rapid

development of versatile, reusable, portable applications. This section describes common

tasks associated with developing Host Publisher EJB applications.

EJB support in Host Publisher is intended for use by enterprises that run their backend

servers using EJB technology. With EJB support in Host Publisher, you can logically (or

physically) partition the Integration Object’s function of navigating and retrieving backend

enterprise data from the presentation and consumption of that data. This processing model is

aligned with the J2EE three-tier application model.

6.7.1 Understanding EJB support in Host Publisher

Host Publisher provides support for executing Integration Objects in EJB containers to take

advantage of the server-side characteristics provided by the EJB architecture. This support

consists of the following parts:

 The

Host Publisher EJB, which is a stateful session EJB capable of running Integration

Objects in an EJB environment. (Stateful means that the EJB maintains a conversational

state with the client for the duration of an application.) This EJB is contained in the EAR

file for each application.



Host Publisher Studio support for the generation of EJB support files for running

Integration Objects. This includes, for each Integration Object, the generation of an EJB

access bean that provides the same signature as the real Integration Object.



Application Integrator support for building applications using the generated EJB support

files and the Host Publisher EJB.

Because the EJB access bean has the same signature as the Integration Object, the EJB

access bean can be used in client-side code exactly as a real Integration Object would be

used. Therefore, the client can be:

 A JSP page or a servlet that uses one or more EJB access beans in a J2EE application

where the Integration Objects execute in an EJB container.

 A Java application client that uses one or more EJB access beans to execute the

Integration Objects in an EJB container.

 A Java application thin client that uses one or more EJB access beans to execute the

Integration Objects in an EJB container.

Refer to the WebSphere documentation Web site for more information about Java application

clients and Java application thin clients:

http://www-1.ibm.com/servers/eserver/iseries/software/websphere/wsappserver/docs/doc.htm

Figure 6-78 shows the components of a typical EJB application:

 The JSPs, packaged together with the EJB access beans in the application .war file,

execute in a Web container.

 The Host Publisher EJB, packaged as an EJB JAR file, executes in a WebSphere EJB

container.