UML Weekend Crash Course™ - To Parent Directory

Session 15—Applying the Activity Diagram to the Case Study 165
Multiple processes may take place at the same time. Model them using the fork bar
and the synchronization bar. The fork initiates multiple processes and the synchronization
bar shows the completion of the multiple processes and the continuation of
activity as a single process.
To model decisions in the process, you have two options. A decision that results
from the completion of an activity is drawn using guard conditions. Each transition
out of the activity is labeled with a unique (mutually exclusive) conditional expression
enclosed in square brackets [ ]. For a decision that is not the result of one specific
activity, use the diamond icon. Each transition out of the diamond decision
point is also labeled with a unique conditional expression enclosed in square
brackets [ ].
When the logical flow of the process needs to return to a previous point in the flow,
use the diamond icon as a merge point diamond. There may be two or more arrows
entering the merge point, but only one exiting the merge point.
End points are drawn using a bull’s-eye symbol. There may be as many end points as
the logic requires. In practice, there should be one transition to an end point for
each Use Case termination option.
QUIZ YOURSELF
1. What part of the Use Case narrative provides the start for your Activity diagram
(See “Building an Activity Diagram for the Case Study.”)
2. What notation do you use to return to a previous place in the Activity diagram
(See “Building an Activity Diagram for the Case Study.”)
3. The Activity diagram offers two ways to handle decisions. When do you use the
diamond symbol for a decision (See “Building an Activity Diagram for the Case
Study.”)
4. What notation do you use to show that a transition triggers multiple processes
(See “Building an Activity Diagram for the Case Study.”)
5. What notation do you use to show that multiple, concurrent paths end and become
one logical path (See “Building an Activity Diagram for the Case Study.”)