The system initiates interactions with secondary actors.A primary actor initiates an interaction with the system.It might be an external server or a web service. Supporting actors may or may not have goals that they expect to be satisfied by the use case, the primary actor always has a goal, and the use case exists to satisfy the primary actor. Supporting Actors: A supporting actor in a use case in an external actor that provides a service to the system under design. The primary actor is often, but not always, the actor who triggers the use case. It has a goal with respect to the system – one that can be satisfied by its operation. Primary actor of a use case is the stakeholder that calls on the system to deliver one of its services. Any individual, group or phenomenon that fits one or more of these categories is a candidate for an actor.Will the system interact with any external hardware or software system?.Which user groups are required to perform secondary functions, such as system maintenance and administration?.Which user groups are needed to execute the system’s most obvious main functions?.Which user groups require help from the system to perform their tasks?.These questions are useful in identifying actors: Eliminate actor candidates who do not have any goals. Includes the actor’s area of responsibility and the goals that the actor will attempt to accomplish when using the system. A single physical instance may play the role of several different actors and a given actor may be played by multiple different instances.Ĭandidate actors include groups of users who will require help from the system to perform their tasks and run the system’s primary or secondary functions, as well as external hardware, software, and other systems.ĭefine each candidate actor by naming it and writing a brief description. Actors do not necessarily represent specific physical entities but merely particular facets (i.e., “roles”) of some entities that are relevant to the specification of its associated use cases.Actors may represent roles played by human users, external hardware, or other subjects.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.An actor in use case modeling specifies a role played by a user or any other system that interacts with the subject.These are called actors which has the following characteristics: For example, the operating environment of a software system consists of the users, devices, and programs that the system interacts with. Each type of external entities with which the system must interact is represented by an actor. Identifying actors is one of the first steps in use case analysis.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |