Abstract
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.
Discussion