Enterprise beans—the big picture

This section shows you the “big picture”—what CICS® support for Enterprise JavaBeans means in general terms. The sections that follow fill in the details.

Sun Microsystem's Enterprise JavaBeans Specification, Version 1.1, defines a model for the development of reusable Java™ server components (known as enterprise beans) that can be used in any application server that provides the services and interfaces defined by the specification.

You can configure CICS as an EJB server. CICS provides a run-time environment where requests for EJB services are mapped to existing or enhanced CICS services.

You can write enterprise beans that give Java clients access to your past investment in CICS applications and data. For example, you can write enterprise beans that:
Figure 1 shows, in simplified form, a CICS EJB application server interacting with its environment. It shows enterprise beans that have been developed on a workstation being installed into the EJB server by a process known as deployment. Once installed in the server, the enterprise beans are executed in a Java Virtual Machine (JVM) at the request of a client program.
Note: The details of Figure 1 are explained in the sections that follow.
Figure 1. A CICS EJB application server. Enterprise beans developed on a workstation are installed into the EJB server by a process known as deployment. They are executed in a JVM at the request of a client program. The details of this picture are explained in the sections that follow.
The picture shows a CICS EJB application server. Within the server are several JVM instances. Outside the server, a cloud represents enterprise bean development. The output of enterprise bean development is an ejb-jar file, which is passed to another cloud representing deployment. The output of deployment is a deployed JAR file in an HFS directory, some security definitions in an external security manager, and some CICS resource definitions in a CSD. The resource definitions are installed into CICS. The deployed JAR file is read by CICS. Having read the deployed JAR file, CICS publishes a reference to the home interface of each enterprise bean in an external namespace.A client looks up the name of a bean in the namespace. It communicates with the CICS EJB server over an IIOP connection.
1 Enterprise beans that use the JCICS classes are not portable to a non-CICS environment.