UML Weekend Crash Course™ - To Parent Directory

SESSION
14
Modeling the Functional View:
The Activity Diagram
Session Checklist
✔ Explaining the purpose and use of the Activity diagram
✔ Explaining the Activity diagram notation
The Activity diagram is part of the Functional view because it describes logical
processes, or functions, implemented using code. Each process describes a sequence of
tasks and the decisions that govern when and how they are done. You must understand
these processes in order to write correct code.
Functional modeling has acquired a poor reputation with the onset of object-oriented
(OO) modeling. But both functional modeling and data modeling provide valuable insight
into software development. OO development methods simply bring the two concepts
together. Functional modeling is still a very basic part of any application design.
Introducing the Activity Diagram
In the past, you used flowcharts, a simple technique with a wide range of applications. The
UML offers an enhanced version of flowcharts in the form of the Activity diagram, the focus
of this session.
Where might you use the Activity diagram There are at least three places in the UML
where an Activity diagram provides valuable insight: workflow, Use Cases, and operations.
Modeling workflow and Use Cases
When modeling a Use Case, you’re attempting to understand the goal that the system must
achieve in order to be successful. Use the Activity diagram to follow the user through a procedure,
noting the decisions made and tasks performed at each step. The procedure may
incorporate many Use Cases (workflow), a single Use Case, or only part of a Use Case as you