Realizability of Collaboration-based Service Specifications

This paper is concerned with compositional specification of services using UML 2 collaborations, activity and interaction diagrams. It addresses the problem of realizability: given a global specification, can we construct a set of communicating state machines whose joint behavior is precisely the specified one? We approach the problem by looking at how collaboration behaviors may be composed using UML activity diagrams. We classify realizability problems from the point of view of each composition operator, and discuss their nature and possible solutions. This brings a new look at already known problems: we show that given some conditions, some problems can already be detected at an abstract collaboration level, without needing to look into detailed interactions.