Actor (UML)
An actor in the Unified Modeling Language (UML) "specifies a role played by a user or any other system that interacts with the subject."[1]
"An Actor models a type of role played by an entity that interacts with the subject (e.g., by exchanging signals and data), but which is external to the subject."[1]
"Actors may represent roles played by human users, external hardware, or other subjects. Note that an actor does not necessarily represent a specific physical entity but merely a particular facet (i.e., “role”) of some entity that is relevant to the specification of its associated use cases. Thus, a single physical instance may play the role of several different actors and, conversely, a given actor may be played by multiple different instances."[1]
UML 2 does not permit associations between Actors.[1][2] Yet, this constraint is often violated in practice since the generalization/specialization relationship between actors is useful in modeling overlapping behaviours between actors.[3]
Actors interact with use cases.
[edit] References
- ^ a b c d "OMG Unified Modeling Language (OMG UML), Superstructure, V2.1.2, pp. 586–588". http://www.omg.org/spec/UML/2.1.2/Superstructure/PDF. Retrieved November 7, 2010.
- ^ "Problems and Deficiencies of UML as a Requirements Specification, s.3.2.". http://www.ifi.uzh.ch/rerg/fileadmin/downloads/publications/papers/IWSSD-10.pdf. Retrieved November 7, 2010.
- ^ "Introduction to UML 2 Use Case Diagrams, Fig. 4". http://www.agilemodeling.com/artifacts/useCaseDiagram.htm. Retrieved November 7, 2010.
[edit] External links
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