Configuring J2EE Session EJBs

Synapta Services Builder J2EE support provides Java 2 Enterprise Edition (J2EE)-compliant accessibility between various host systems and supported application servers. Attachmate J2EE support uses the Java Naming and Directory Interface (JNDI) to deploy enterprise applications to your application server. These applications use both session Enterprise JavaBean version 1.1 (EJB) and connector functionality. The Attachmate J2EE connector functions as a resource adapter and is written to the Sun J2EE Connector Architecture Specification, version 1.0, while the session EJB accesses host data through the connector.

Note What is a resource adapter?  A resource adapter is a system-level software driver used by an application server or client to connect to an enterprise system.
A resource adapter plays a central role in the integration and connectivity between your enterprise system and an application server — it is the point of contact between application components, application servers, and enterprise information systems. The Attachmate J2EE connector is a resource adapter.

Because both the application servers and the Attachmate J2EE connector adhere to the industry-standard J2EE Connector architecture, you are ensured of complete compatibility between the supported application servers and your enterprise system.

Synapta Services Builder J2EE support integrates CICS, IMS, UTS, T27, VT, and 3270/5250 IBM host systems with the following J2EE-compliant application servers:

With the management tools provided in the Synapta Services Builder you can easily register your application servers, package your task file as an application containing both session EJB and connectors, and then deploy it to whatever application server you are running.

The architecture

The Synapta Services Builder session EJBs meet the Enterprise JavaBean 1.1 specification. The Attachmate EJB interface contains one method per task in each task file for which an EJB is generated and each method is given the name of its associated task. EJBs are generated using the information you supply in the MCS management console.

Note What is a session EJB?   A session bean is created by a client and commonly exists for the duration of a single client/server session. They provide a component architecture for the development and deployment of object-oriented, distributed, enterprise-level applications. Session bean objects can be either stateless or they can maintain state across methods and transactions.

When an EJB is generated a JAR file is created, along with a connector RAR file, and then deployed to your selected application server on a per project basis. Projects can contain multiple tasks.

How do the Attachmate session EJBs handle state?

Both stateful and stateless session EJBs are supported. You select the state management mode you want to use when you create the EJB. The default option is to create EJBs that maintain state and are, therefore, stateful.

It is important to remember that the number of pools that you configure to run your enterprise applications must take into account the number of stateful and stateless EJBs that have been configured and deployed.

EJB application session pool requirements

In this illustration the needs of a 100 stateless EJBs are being handled by just 10 connectors. Your requirements may vary.

You can verify whether a session is free or allocated by monitoring the configured pools that are running on the Runtime Service for Screens. In the MCS for Screens management console, select Monitor, then the Pools tab. On the Pools page, check the State column to verify if a pool or session is free or allocated.

Related Topics
Bullet Using J2EE Connector Architecture, Overview
Bullet Registering Application Servers
Bullet Packaging J2EE Session EJBs
Bullet Deploying J2EE Session EJBs
Bullet J2EE Sample Code using a Stateful Session EJB in a Web Application
Bullet J2EE Sample Code
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