Activity diagram
| UML diagrams |
|---|
| Structural UML diagrams |
| Behavioral UML diagrams |
Activity diagrams are graphical representations of workflows of stepwise activities and actions[1] with support for choice, iteration and concurrency. In the Unified Modeling Language, activity diagrams are intended to model both computational and organisational processes (i.e. workflows)[2][3]. Activity diagrams show the overall flow of control.
Activity diagrams are constructed from a limited number of shapes, connected with arrows[4]. The most important shape types:
- rounded rectangles represent actions;
- diamonds represent decisions;
- bars represent the start (split) or end (join) of concurrent activities;
- a black circle represents the start (initial state) of the workflow;
- an encircled black circle represents the end (final state).
Arrows run from the start towards the end and represent the order in which activities happen.
Hence they can be regarded as a form of flowchart. Typical flowchart techniques lack constructs for expressing concurrency[citation needed]. However, the join and split symbols in activity diagrams only resolve this for simple cases; the meaning of the model is not clear when they are arbitrarily combined with decisions or loops.
While in UML 1.x, activity diagrams were a specialized form of state diagrams[5], in UML 2.x, the activity diagrams were reformalized to be based on Petri net-like semantics, increasing the scope of situations that can be modeled using activity diagrams[6]. These changes cause many UML 1.x activity diagrams to be interpreted differently in UML 2.x
See also [edit]
- Business Process Modeling Notation
- Control flower graph
- Data flow diagram
- Event-driven process chain
- List of UML tools
- Pseudocode
- State diagram
References [edit]
- ^ Glossary of Key Terms at McGraw-hill.com. Retrieved 20 July 2008.
- ^ UML Revision Task Force. OMG Unified Modeling Language Specification, Version 1.4 (final draft). February 2001.
- ^ J. Rumbaugh, I. Jacobson, and G. Booch. The Unified Modeling Language Reference Manual. Addison-Wesley, 1999.
- ^ OMG Unified Modeling Language Superstructure Specification, version 2.1.1. Document formal/2007-02-05, Object Management Group, February 2007. http://www.omg.org/cgi-bin/doc?formal/2007-02-05.
- ^ Dumas, Marlon, and Arthur HM Ter Hofstede. "UML activity diagrams as a workflow specification language." ≪ UML≫ 2001—The Unified Modeling Language. Modeling Languages, Concepts, and Tools. Springer Berlin Heidelberg, 2001. 76-90.
- ^ Störrle, Harald, and J. H. Hausmann. "semantics of uml 2.0 activities." Proceedings of the IEEE Symposium on Visual Languages and Human-Centric Computing. 2004.
External links [edit]
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