Tool Mentor: Detailing a Use Case Using Rational Rose
Purpose
This tool mentor describes how to represent activity diagrams under a business use case in Rational Rose.
This section provides links to additional information related to this tool mentor.
Overview
The following is a summary of the steps you perform to create an
activity diagram in a use-case model:
-
Create
an activity diagram in a use case
- Create
and describe an activity state in the diagram
- Connect
activity states with transitions
- Create
synchronization bars
- Create
decisions with guard conditions
For detailed information about Activity Diagrams, see:
1. Create
an activity diagram in a use case
Activity diagrams can be very effective in illustrating the workflow
of various events in a use-case diagram. The flow of events of a use
case describes what needs to be done by the system in order to
provide value to an actor. Also, use case diagrams present a high
level view of how the system is used as viewed from an outsider's
(actor's) perspective. You can use activity diagrams to specify
and define each event in a use case diagram.
For
complete details on how to create an activity diagram, see the Creating
an Activity Diagram topic in the Rational Rose online help.
2. Create
and describe an activity state in the diagram
An activity represents the performance of a task or duty in a
workflow. It may also represent the execution of a statement in a
procedure. An activity is similar to a state, but expresses the
intent that there is no significant waiting (for events) in an activity.
For
more information on activities, see the Activity
topic in the Rational Rose online help.
3. Connect
activity states with transitions
Transitions connect activities with other model elements. You can
create a transition between two activities or between an activity and
a state.
For
more information on transitions, see the
State Transition topic in the Rational Rose online help.
4. Create synchronization bars
Synchronizations enable you to see a simultaneous workflow in an
activity diagram. Synchronizations visually define forks and joins
representing parallel workflow.
A fork construct is used to model a single flow of control that
divides into two or more separate, but simultaneous flows. Every fork
that appears on an activity diagram should ideally be accompanied by
a corresponding join. A join consists of two of more flows of control
that unite into a single flow of control. All model elements (such as
activities) that appear between a fork and join must complete before
the flow of controls can unite into one.
For
more information on synchronization bars, see the Synchronizations
topic in the Rational Rose online help.
5. Create decisions with
guard conditions
A decision represents a specific location on an activity diagram
where the workflow may branch based upon guard conditions. There may
be more than two outgoing transitions with different guard
conditions, but for the most part, a decision will have only two
outgoing transitions determined by a Boolean expression. You can place
guard conditions on transitions to or from almost any element on an
activity diagram.
For
more information on decisions and guard conditions, see the Decisions
topic in the Rational Rose online help.
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