Connecting to enterprise information systems

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

Java™ EE application development for enterprise information systems

The J2EE Connector tools enable you to create Java EE applications running on WebSphere® Application Server to access operations and data on enterprise information systems (EIS) such as CICS® 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, IMS, Sap, Siebel, PeopleSoft, JD Edwards, and Oracle into the Java EE platform; J2C tools offer a number of qualities of service that can be provided by an application server:
  • security credential management
  • connection pooling
  • transaction management
These qualities of service are provided by 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.
Restriction: The artifacts that are created from the following J2C wizards are not supported on the Liberty server:
  • Command Bean
  • J2C Bean
  • Web Page, Web Service, or EJB from J2C Java Bean
Only classes that are generated from the CICS/IMS Data Binding wizard will be supported on the Liberty server, provided that the marshall.jar file is packaged with the deployed application. Note that marshall.jar is not part of the Liberty runtime. If you have a licensed copy of RAD, marshall.jar is listed in the redistributable files section of the documentation. The licensed redistributable file is located in the plug-in com.ibm.ccl.commonj.connector.metadata. You also need to follow instructions in Enabling generated record data in outbound optimized local adapter connections in Liberty to add marshall.jar to the Liberty server.
Important: J2C beans are formally supported and tested on the WebSphere Application Server classic server. Use in other Java environments should work, but is not tested extensively. If there are issues with the generated code and it can be isolated as such within a WebSphere Application Server classic server environment, then it will be supported.

The following diagram illustrates the architecture of the J2EE connector tools within the development environment:

J2C Overview

Resource adapters

In order for your application to communicate with an enterprise information system, 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 on an application server. These resource adapters (RAR files) can be imported into the workbench and used to create enterprise applications.

These resource adapters are shipped with the product:

Importers

In order for your application to process source files from the CICS or IMS information system, the data needs to be imported and mapped to Java data structures. Three importers are available for you to use in your application: C Importer, COBOL Importer, and 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 using J2C resource adapters, the Java applications must handle two tasks:
  • 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/I importer is not supported on Linux.

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

J2C wizards

The J2C wizards enable you to create J2C applications, either as stand-alone programs or as added function 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
  • Facilitate the creation of Java classes and methods to access the transformed source data.

A typical J2C application consists of a J2C 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. When you have created a J2C bean, you then can create Web pages, an EJB, or a Web Service for your J2C bean.

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

J2C wizards

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