Connecting to enterprise information systems

J2EE Connector (J2C) tools, resource adapters, and file importers allow you to create J2EE Connector artifacts, which you can use to create enterprise applications.

J2EE Application Development for Enterprise Information Systems

The J2EE Connector Tools enable you to create J2EE applications running on WebSphere® Application Server to access operations and data on enterprise information systems (EIS) such as CICS® ECI or IMS™. The key technology used to provide this type of access is resource adapters implemented according to the J2EE Connector Architecture. The purpose of the J2EE Connector Architecture is to connect Enterprise Information Systems, such as CICS and IMS, into the J2EE platform; it offers a number of qualities of service that can be provided by a J2EE application server. These qualities of service include These qualities of service are provided by means of system-level contracts between a resource adapter provided by the connector (CICS Transaction Gateway or IMS Connect, for example) , and the application server. There is no need for any extra program code to be provided by the user. Thus the programmer is free to concentrate on writing the business code and need not be concerned with providing quality of service. The J2EE Connector Architecture defines a programming interface called the Common Client Interface (CCI). This interface can be used, with minor changes, to communicate with any EIS.

The following diagram illustrates the architecture of the J2EE Connector tools within the development environment:
J2C Overview

Resource Adapters

A resource adapter is a system-level software driver that is used by a Java™ application to connect to an enterprise information system (EIS). The resource adapters reside on the application server and provide connectivity between the EIS, the application server and the enterprise application. Applications deployed on the application server communicate with the resource adapter using the CCI. The RAR contains all the information necessary for installing, configuring and running a JCA Resource Adapter.; they can be provided by and used by any vendor, provided they comply with the J2EE Java Connector Architecture specification.

In order for your application to communicate with an Enterprise Information System, like CICS or IMS, a resource adapter is required to create a communication link. J2C tools include a number of resource adapters that allow you to create and test J2C enterprise applications in its unit test environment. These resource adapters (RAR files) can be imported into the workbench and used to create enterprise applications.

Four resource adapters are shipped with the product:

For more information about CICS, see CICS ECI Resource Adapter; for more information about IMS, see IMS Resource Adapter

Importers

In order for your application to process source files from the CICS or IMS information systems, the data needs to be imported and mapped to Java data structures. Two importers are available for you to use in your application;

the C Importer and the COBOL Importer. These tools allow you to import C or COBOL programs into your application through a process of data type transformation. The importers map the data-types contained within the source file so that your application can access the source material. In other words, if you are coding Java™ applications to access transaction programs written in COBOL or C in CICS or IMS via J2C resource adapters, the Java applications will need to

For more information about the COBOL Importer, see COBOL Importer; for more information about the C Importer, see C Importer.

J2C Wizard

The J2C wizard enables you to create J2C applications, either as a standalone program, or as added functionality to existing applications. The wizard dynamically imports your selected resource adapter, allows you to set the connection properties to connect to the EIS servers, guides you through the file importing and data mapping steps, and facilitates the creation of Java classes and methods to access the transformed source data.

The following diagram illustrates the flow of the J2C Java bean wizard through the creation of a J2C Java bean, a data bean, and optional deployment artifact:


J2C wizards

The process of using the J2C wizard to build a Java application that runs an EIS transaction is summarized by the following steps:
  1. The J2C wizard imports C or COBOL definitions of the EIS transaction input and output messages into the Java Data Binding wizard to map to Java data structures. This wizard creates Java data bindings for the input and output messages.
  2. The J2C wizard provides Java data bindings to the J2C Java bean wizard. This wizard creates a J2C Java bean with methods that can be used to run EIS transactions on the host.
  3. The J2C wizard creates a J2EE resource that you can associate with the J2C Java bean. This J2EE resource can be deployed to WebSphere Application Server and used to run your EIS transactions. The types of J2EE resources that can be created from a J2C Java bean are
    • JSP
    • Faces JSP
    • Web Service
    • EJB
  4. The wizard exports the J2EE resource, packaged as an EAR file, so that it can be deployed to and run on a stand alone WebSphere Application Server.
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