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

security credential management
connection pooling
transaction management

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:

Resource Adapters

In order for your application to communicate with an EIS, a resource adapter is required to create a communication link between your application and the EIS. 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:

CICS ECI Adapter 7.0.0
CICS ECI Adapter 6.0.2.1
CICS ECI Adapter 5.1.0.2
IMS resource adapter 9.1.0.2.4
IMS resource adapter 9.1.0.1.5

For more information about CICS, see CICS ECI Resource Adapter. Also, all the supported software and hardware for the CICS Transaction gateway is listed http://www-1.ibm.com/support/docview.wss?uid=swg21239203 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. Three importers are available for you to use in your application: the C Importer, the COBOL Importer and the PL/I Importer.

These tools allow you to import COBOL, C or PL/I 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, C, or PL/I in CICS or IMS via J2C resource adapters, the Java applications will need to

serialize values from Java to the COBOL, C, or PL/I byte buffer that the IMS or CICS program expects
deserialize the returned value from the COBOL, C, or PL/I buffer for processing in the Java application.

Note: The PL/1 importer is not supported on Linux^®.

For more information about the COBOL Importer, see COBOL Importer; for more information about the C Importer, see C Importer; for more information about the PL/I Importer. see Setting PL/I Importer Preferences

J2C Wizards

The J2C wizards enable you to create J2C applications, either as standalone programs, or as added functionality to existing applications. The wizards dynamically import your selected resource adapter, allow you to set the connection properties to connect to the EIS servers, guide you through the file importing and data mapping steps, and facilitate the creation of Java classes and methods to access the transformed source data.

A typical J2C application consists of a J2C Java bean with one or more methods that call EIS functions. For CICS and IMS, the input and outputs to these functions are data binding classes that are created by the CICS/IMS Java Data Binding Wizard. Once you have created a J2C Java bean, you can then create Web pages, an EJB or a Web Service for your J2C Java bean.

Types of J2C Wizards Available

CICS or IMS Java Data Binding wizard: You can create the data binding classes on their own. These classes are used in J2C Java bean methods that invoke CICS or IMS functions.
Command Bean wizard: You can use this wizard (optionally) to expose selected methods as a command bean.
J2C Java bean wizard: You can use this wizard to create a Java bean that communicates with an Enterprise Information System through the J2EE Connector Architecture (JCA).
Web page, an EJB or WebService to deploy your J2C Java bean wizard: You can use this wizard to create a J2EE resource that wraps the functionality provided by a J2C Java bean. For example, you can create a JSP to deploy your J2C Java bean on WebSphere server.
Java Connector Migration wizard: You can use this wizard to migrate JCA applications created in WebSphere Studio Application Server Integration Edition applications into Rational^® Application Server projects.

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: