WebSphere Application Server - IBM Redbooks

Actors can be identified by asking users questions such as who uses the system
and who manages the system. In our Online Catalog sample the answers to
these questions are:
► Buyer
► Business owner
As you can see, in our example these actors are fairly simple and distinct. The
function of each within the application appears to be different, based on the
names. If the distinction is not as clear in your application, consider things such
as security levels or training required for the user.
Use cases
Use cases depict interaction between the actor and the system. They represent
functionality available to an actor. A collection of transactions that can be
identified as a unit of work is a good candidate for a use case. Use cases are
depicted by a ellipse in UML notation, as shown in Figure 2-3.
Use Case
Figure 2-3 UML notation of a use case
Use-case model analysis usually starts with an overall main use-case diagram
with actors and major use cases. In the case of our sample application, we see
two main interaction types with the application. These two interactions are
identified as:
► Maintain inventory
► Buys item
Figure 2-4 on page 25 shows the main use-case diagram for our sample. You
can see the major use cases and the relationship with the actors.
24 IBM WebSphere Application Server - Express V5.0.2 Developer Handbook