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
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:
- CICS ECI
Adapter 5.1
- CICS ECI
Adapter 6.0.0
- IMS resource
adapter 9.1.0.1.1
- IMS resource
adapter 9.1.0.2
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
- serialize values from Java to the COBOL or C byte buffer that
the IMS or CICS program
expects
- deserialize the returned value from the COBOL or C buffer for processing
in the Java application.
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:

The process of using the J2C wizard to build a Java application that runs an EIS transaction
is summarized by the following steps:
- 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.
- 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.
- 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
- 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.