IBM Branch Transformation Toolkit 5.1 Migration and Usage Guidelines

Chapter 1. Introduction to IBM Branch Transformation Toolkit 15

initialization for some application logic layer components such as the CHA,

CHA formatter service, and services.

1.5 Concept mappings

Branch Transformation Toolkit 5.1 has many additions and enhancements when

compared with Branch Transformation Toolkit 4.3. In this section, we map the

concepts from Branch Transformation Toolkit version 4.3 to version 5.1.

1.5.1 Toolkit application architecture

A new feature of Branch Transformation Toolkit 5.1 is that it is based on the

J2EE standard architecture. On the client side, the Java client application

remains the same as in version 4.3. The existing code can be used in the new

toolkit environment without modification. However, the Branch Transformation

Toolkit application server tier has been split into two layers to separate the

presentation from the business logic. The application presentation layer residing

in the Web container of the J2EE environment is now restricted to creating

requests for business logic hosted in the application-logic layer. For non-Java

clients, the application presentation layer provides view navigation based on the

Apache Struts framework. The application-logic layer focuses on performing the

business logic requests.

This change enables applications to use many more capabilities of WebSphere

Application Server or WebSphere Business Integration Server Foundation while

providing backward compatibility with version 4.3. Version 5.1 of the Branch

Transformation Toolkit provides of a set of entirely new components that perform

and support a business process, and helps access services and data from the

back-end enterprise tier.

1.5.2 Application server components

This section describes the difference between the old version and the new

version of the application server components resulting from the new architecture.

Many old toolkit components that ran in the application server have been

modified or changed significantly. These components include the following:

Flow processors

The flow processors do not exist in application servers any longer. They have

been replaced with business processes. Using the client/server interfaces, toolkit

clients now pass requests to an invoker or to a WebSphere Server Integration

Foundation action. These requests call a business process component or single

action EJBs in the application logic layer.

16 IBM Branch Transformation Toolkit 5.1 Migration and Usage Guidelines

Server operations

Server operations do not exist in application servers now. Stepped operations

have been replaced with business processes, and non-stepped operations with

business processes or single action EJBs. Through the client/server interfaces,

toolkit clients pass requests to an invoker or a WebSphere Server Integration

Foundation action that calls the business process component or single action

EJBs in the application logic layer.

Server side components

This section describes the changes made to the server components, based on

the container they are used by.

Shared components across containers

These components can be shared across the Web container and the EJB

container, that is, they can be used both by the application presentation layer

and the application logic layer.

򐂰 Common Hierarchical Area (CHA)

This component uses J2EE technology to wrap contexts as EJBs so that they

can be accessed by any entity running in the EJB container. This enables a

business process to get the data it needs. Since CHA contexts are EJBs,

non-toolkit applications can use CHA to contain general global session

information. This is a new concept that has been introduced in version 5.1.

򐂰 CHA contexts

These contexts, which run in the application server, are different from those

running in the Java client side. Compared to contexts running on the Java

client side, the CHA contexts have additional wrapping so that they can exist

as EJBs. There is no connection between the contexts and CHA contexts.

This too is a new concept introduced in version 5.1.

򐂰 Events

The events running in the application server side have a different structure

from those running in the Java client side. The application server side events

use Java Message Service (JMS) for events propagation.

򐂰 Externalizers

Externalizers exist in both the layers, except that the application logic layer

does not contain externalizers for toolkit entities that are related purely to

presentation, such as flow processors and views.