Chapter 5. Actors and Use Cases
A use case is a description of the usage of a system from one or more users' point of view. The usage accomplishes some action of value for some user. The value the use case provides may not be to the user triggering the use case. The user can be a person, another system, or even an internal system entity such as a timer. We use the term actor because it is a more generic term that does not imply a human user.
A use case describes the interaction between the actor and the system. The analyst specifies the use case by completing a standard collection of information. The collection includes the following: