8 IBM Branch Transformation Toolkit 5.1 Migration and Usage Guidelines
1.3 Branch Transformation Toolkit 5.1 architecture
This section introduces the prime architecture of Branch Transformation Toolkit
5.1. The new version is based on the J2EE standard. The development
environment for toolkit applications is integrated with WebSphere Studio
Application Developer or WebSphere Studio Application Developer Integration
Edition, which are based on the Eclipse Platform. The runtime environment for
toolkit applications is based on WebSphere Application Server or WebSphere
Business Integration Server Foundation.
The architecture of a Branch Transformation Toolkit 5.1 application solution is
based on a logical three-tier model:
򐂰 Back-end enterprise tier
򐂰 Application server tier
򐂰 Client tier
Figure 1-2 on page 9 depicts these tiers.
Chapter 1. Introduction to IBM Branch Transformation Toolkit 9
Figure 1-2 The logical tiers in Branch Transformation Toolkit architecture
Client tier
BTT data
context
Java client
BTT panel (AWT)
Application server tier
Application presentation layer
(Web container)
EJB
Application logic layer
(EJB container)
EJB
Struts action
Struts action servlet &
request processor
View
Struts form
BTT data
context
EJB
WSIF/
EJB
BTT data
context
BTT EJB
Process Choreographer
Micro flow
BTT
BTT data
context
BTT client side
micro flow
Services
WSIF
Invokers
WSIF/
EJB
Back-end enterprise tier
JDBC
database services
JCA resource
adapters
Data
WSIF
10 IBM Branch Transformation Toolkit 5.1 Migration and Usage Guidelines
The client tier is responsible for presenting an interface to the user in a client
device. The Branch Transformation Toolkit 5.1 supports the following types of
clients:
򐂰 Java clients running as applets in a browser or as Java applications
For Java clients, the toolkit provides a set of graphical user interface (GUI)
JavaBeans™ to build the client user interface and a mechanism to navigate
the application views.
򐂰 HTML browser clients
For HTML browser clients, the toolkit’s Struts Extension framework on the
application presentation layer of the application server tier manages the user
interface and view navigation.
The application server tier has two parts:
򐂰 The application presentation layer
The application presentation layer is responsible for creating a request for the
invocation of business logic that is hosted within the application logic layer. In
HTML browser clients, the presentation layer is also responsible for providing
the view navigation. The application presentation layer converts an action
carried out by a user in the user interface into a Web Services Invocation
Framework (WSIF) message or Enterprise JavaBean (EJB™) method
invocation, which the presentation layer then sends to the application logic
layer.
򐂰 Application logic layer
The application logic layer is responsible for performing the business process
that fulfils the presentation layer request. A business process consists of a set
of activities and may involve accessing and manipulating enterprise data and
performing financial service procedures in the back-end enterprise tier.
The application logic layer can use two mechanisms for performing the
business process. If the application server tier is running on WebSphere
Business Integration Server Foundation, the application logic layer can use
the Business Process Choreographer and work area features. If the
application server tier is running on WebSphere Application Server, the
application logic layer can use a Single Action EJB. For more details about
Business Process Choreographer and Single Action EJB, refer to 1.4, “Terms
and definitions” on page 11.
The back-end enterprise tier consists of enterprise level databases and older
systems that provide existing business logic and services. The application logic
layer communicates with these databases and systems through J2EE Connector
Architecture (JCA) connectors, database services, and formatters. The

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