UCM: Use Case Models

UCM is a subset of UML that focuses on use case models.

A use case model consists of several types of elements: actors, use cases, associations, and relationships between use cases.

A use case has a name and an elaboration. A use case may be abstract.

An actor has a name.

The source and target of a use case relationship is a use case. Use case relationships include generalization (UC4 and UC5 are special cases of UC2), includes (UC1 calls UC5 as a sub-procedure), and extends (UC6 catches exceptions thrown by UC1).

An association has two endpoints. And endpoint has a reference (one end must reference an actor and the other a use case) and may or may not be navigable (i.e. have an arrowhead indicating if the actor or the use case initiates a message exchange.)

Create a UML class diagram modeling UCM.