Actors

Actors represent system users. They help define the system and give a clear picture of what the system should do. It is important to note that an actor interacts with, but has no control over, the use cases.

An actor is someone or something that:

• Interacts with or uses (but is not part of) the system.
• Provides input to and receives information from the system.
• Is external to the system and has no control over the use cases.

Actors are discovered by examining:

• Who directly uses the system.
• Who is responsible for maintaining the system.
• External hardware used by the system.
• Other systems that need to interact with the system.

An actor is a stereotype of a class and is depicted as a "stickman" on a use-case diagram. The name of the actor is displayed below the icon.