Actor (UML)

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File:Use Case diagram V1.JPG
UML use case diagram with two actors and several use cases.

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] The use of generalization/specialization relationship between actors is useful in modeling overlapping behaviours between actors and does not violate this constraint since a generalization relation is not a type of association.[3]

Actors interact with use cases.

References

  1. 1.0 1.1 1.2 1.3 Lua error in package.lua at line 80: module 'strict' not found.
  2. Lua error in package.lua at line 80: module 'strict' not found.
  3. Lua error in package.lua at line 80: module 'strict' not found.

External links

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