On the Extension of UML with Use Case Maps Concepts

Descriptions of reactive systems focus heavily on behavioral aspects, often in terms of scenarios. To cope with the increasing complexity of services provided by these systems, behavioral aspects need to be handled early in the design process with flexible and concise notations as well as expressive concepts. UML offers different notations and concepts that can help describe such services. However, several necessary concepts appear to be absent from UML, but present in the Use Case Map (UCM) scenario notation. In particular, Use Case Maps allow scenarios to be mapped to different architectures composed of various component types. The notation supports structured and incremental development of complex scenarios at a high level of abstraction, as well as their integration. UCMs specify variations of run-time behavior and scenario structures through sub-maps "pluggable" into placeholders called stubs. This paper presents how UCM concepts could be used to extend the semantics and notations of UML for the modeling of complex reactive systems. Adding a "UCM view" to the existing UML views can help bridging the gap separating requirements and use cases from more detailed views (e.g. expressed with interaction diagrams and statechart diagrams). Examples from telecommunications systems are given and a corresponding design trajectory is also suggested.