WebSphere Application Server - IBM Redbooks

2.2.1 Use-case analysis
The use-case analysis describes the functional requirements of the application
under development. It defines how users in specific roles will use the system
through use cases. The use case is from the user’s point of view and does not
describe how tasks within the application are accomplished.
Note: Throughout this publication, we will use a sample called the Online
Catalog to illustrate the various features of WebSphere Application Server -
Express. The application will be a simple one that provides a means of
publishing an inventory of goods on the Web and allowing customers to place
orders via e-mail or by phone.
Details about the sample application can be found in Appendix C, “Online
Catalog application” on page 611.
A use-case analysis basically includes the following elements:
► Actor
► Use case
► Communication associations between actors and use cases
► Relationships between use cases
► Flow of events and system sequence diagrams
Together these items provide an overview of the functional requirements and
document the expected usage, user interactions, and behavior of the system in
different styles and depth. The level of detail you go into is determined by the size
and complexity of the application. In the case of our simple application, we will
define the use cases and actors, but will not be building any detailed diagrams.
Actors
The first step in designing the application flow is to determine who will be
interacting with the application and what types of activities they will perform. The
people that interact with the application are known as actors in UML and are
represented by a stick figure in the following figures, as shown in Figure 2-2.
Actor
Figure 2-2 UML notation of an actor
Chapter 2. Application design 23