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

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

Figure 9-13 depicts the WSDL editor showing the interface definition for the

Trader system process.

Figure 9-13 WSDL editor showing the Trader system process interface

9.3 Developing business processes

This section describes how to develop a BPEL process using WebSphere Studio

Application Developer Integration Edition. It first describes the design of the

process and then explains in detail how the BPEL editor of Integration Edition

was used to visually construct the process. Finally, it discusses process

deployment and configuration of WebSphere Business Integration Server

Foundation.

9.3.1 EIS integration into BPEL processes

In our approach for EIS integration, EIS services are invoked from system

processes. In the system process, the decision is made regarding how the

service is called. If the service invocation requires data transformation, an EIS

Chapter 9. Integration into business processes 267

component might be called. In case a remote service has to be invoked, a JMS

binding can be used to communicate with the service.

The following sections describe how to develop the trader system process that

we designed in 6.4.1, “The stock trade scenario” on page 137.

In this system process we demonstrate the invocation of the EIS functions using

three different integration styles:

򐂰 We directly invoke the EIS service using the IMS bindings that we have

created with the WebSphere Studio Application Developer Integration Edition

tools.

򐂰 We invoke the EIS component that we have developed using direct EJB calls,

meaning that we call a local EIS component.

򐂰 We invoke the EIS component using sender beans and Message Driven

Beans, means that we use JMS technology to call a remote EIS component.

Each of these integration styles has specific characteristics that affect the

development of the process. Calling the IMS service directly requires that data

transformations are performed in the process. Data transformation can be

implemented in the BPEL process either by using Transformation nodes or by

coding Java Snippets.

If the EIS component is invoked by JMS messages, the system process includes

a send activity to send the message. The BPEL process may also include a pick

activity to receive the confirmation message. because the process has to wait for

the message, the process has to be marked as interruptible process. This means

the process itself has to be triggered by using JMS. Introducing a pick activity

also requires the configuration of a correlation set to distinguish the trigger and

initialize messages for the process from reply messages sent by the EIS

component.

9.3.2 Developing the BPEL process

This section describes the steps to create the trader system process in detail. It

first explains how to create a service project and the basic outline of the process.

Then, it describes the creation of service bindings that are used in the BPEL

process. Finally, it demonstrates the use of the BPEL editor by successively

adding the EIS service invocations to the process.

Creating a service project and a BPEL process

When you start WebSphere Studio Application Developer Integration Edition, the

Business Integration perspective opens by default. The Business Integration