Book contents
- Frontmatter
- Contents
- Preface
- 1 Introduction
- 2 General Diagramming Guidelines
- 3 Guidelines for Common UML Modeling Elements
- 4 UML Use-Case Diagrams
- 5 UML Class Diagrams
- 6 UML Package Diagrams
- 7 UML Sequence Diagrams
- 8 UML Communication Diagrams
- 9 UML State Machine Diagrams
- 10 UML Activity Diagrams
- 11 UML Component Diagrams
- 12 UML Deployment Diagrams
- 13 UML Object Diagrams
- 14 UML Composite Structure Diagrams
- 15 UML Interaction Overview Diagrams
- 16 UML Timing Diagrams
- 17 Agile Modeling
- Bibliography
- Index
10 - UML Activity Diagrams
Published online by Cambridge University Press: 17 December 2010
- Frontmatter
- Contents
- Preface
- 1 Introduction
- 2 General Diagramming Guidelines
- 3 Guidelines for Common UML Modeling Elements
- 4 UML Use-Case Diagrams
- 5 UML Class Diagrams
- 6 UML Package Diagrams
- 7 UML Sequence Diagrams
- 8 UML Communication Diagrams
- 9 UML State Machine Diagrams
- 10 UML Activity Diagrams
- 11 UML Component Diagrams
- 12 UML Deployment Diagrams
- 13 UML Object Diagrams
- 14 UML Composite Structure Diagrams
- 15 UML Interaction Overview Diagrams
- 16 UML Timing Diagrams
- 17 Agile Modeling
- Bibliography
- Index
Summary
UML activity diagrams are the object-oriented equivalent of flow charts and data-flow diagrams from structured development (Gane and Sarson 1979). In UML 1.x, UML activity diagrams were a specialization of UML state machine diagrams, although in UML 2.x they are full-fledged artifacts. UML activity diagrams are used to explore the logic of
■ a complex operation,
■ a complex business rule,
■ a single use case,
■ several use cases,
■ a business process,
■ concurrent processes,
■ software processes.
General Guidelines
Place the Starting Point in the Top Left Corner
A starting point is modeled with a filled circle, using the same notation that UML state chart diagrams use. Every UML activity diagram should have a starting point, and placing it at the top left corner reflects the way that people in Western cultures begin reading. Figure 41, depicting the business process of enrolling in a university, takes this approach. Another good option is to place it at the top center of the diagram.
Include an Ending Point
An ending point is modeled with a filled circle with a border around it. Some people's style is to make ending points optional—sometimes an activity is simply a dead end—but if this is the case, then there is no harm in indicating that the only activity edge (formerly known as a transition) is to an ending point. That way, when someone else reads your diagram, they know that you have considered how to exit these activities.
- Type
- Chapter
- Information
- The Elements of UML™ 2.0 Style , pp. 113 - 131Publisher: Cambridge University PressPrint publication year: 2005