Managing Information Access to an Enterprise Information System Using J2EE and Services Oriented Architecture

102 Managing Information Access to an EIS Using J2EE and Services Oriented Architecture

either a call back mechanism or some intermediate event store that is used for

triggering and sending the events to the resource adapter. Finally, the message

endpoint is notified of the event by a call to MessageEndPoint.

The delivery of events from the EIS can also be transacted using container

managed transactions and Java Transaction API (JTA). This method of delivery

uses the transaction management contract and controlling the transaction

boundaries using the beforeDelivery and afterDelivery methods. These methods

signify when the application server should enlist an XAResource to start and end

the transaction.

For more information, see the JCA 1.5 specification at:

http://java.sun.com/j2ee/connector/download.html

5.3 The integration building block using J2C

This section describes the integration building blocks that use J2C and how the

IBM CICS J2C resource adapter helps to solves the scenario problem. It

describes the components of the building block and the system architecture that

we used for the EIS integration.

5.3.1 Scenario problem statement

Many EIS have their services and functions exposed through the use of a J2C

resource adapter that is 1.0 or 1.5 compliant. Application components are more

often being built to run in a J2EE application server. To manage EIS data and use

existing functionality, the application components use resource adapters to

interact with these enterprise systems.

For our specific scenario, the ITSO Trading Firm has an Internet Trading System

J2EE application that processes trade requests made over the Web. The Internet

Trading System uses a company listing to verify whether buy or sell requests can

be made through the system. The information for the company list is stored in a

CICS system that the firm owns.

Our Buy Shares scenario requires verification of the order against the company

list. The trade shares business component of the Internet Trading System uses

the list of available companies from which customers are allowed to buy shares.

The component needs this process to be quick, synchronous retrieval from the

CICS system. This process is facilitated by the CICS resource adapter which can

be integrated into the trade shares business component as a service.

Chapter 5. Using J2EE Connector Architecture 103

5.3.2 System architecture

The Internet Trading System is a J2EE application component which includes

BPEL processes that are running in the Business Process Container, JSPs, and

EJB. This scenario concentrates on the business process that is implemented

using BPEL and its associated system processes.

The Internet Trading System runs in the WebSphere Business Integration Server

Foundation application server space. The trading system BPEL process

executes requests on the CICS system via the J2C resource adapter. The

resource adapter is configured to make calls to the CICS system through the

CICS Transaction Gateway that is running on a z/OS system.

The application is running on WebSphere Business Integration Server

Foundation with the resource adapter. The CICS system is on a z/OS platform

that is internal to the company. Figure 5-2 shows the components of the system.

Figure 5-2 System view of components

The trade shares business component makes a request on the system process

requesting the company list information. The system process makes a service

call on the CICS resource adapter exposed as a service. The GetCompanyList

operation is invoked via a partner link in the system process, and the results are

returned to the trade shares business process.

WebSphere Business Integration

Server Foundation

Trading

System

Application

CICS

JCA

CICS

Transaction

Gateway

CICS

EIS System