Abstract

Live sequence charts (LSCs) have been de ned recently as an extension of message sequence charts (MSCs � or their UML variant, sequence diagrams) for rich inter-object speci cation. One of the main additions is the notion of universal charts and hot, mandatory behavior, which, among other things, enables one to specify forbidden scenarios. LSCs are thus essentially as expressive as statecharts. This paper deals with synthesis, which is the problem of deciding, given an LSC speci cation, if there exists a satisfying object system and, if so, to synthesize one automatically. The synthesis problem is crucial in the development of complex systems, since sequence diagrams serve as the manifestation of use cases | whether used formally or informally | and if synthesizable they could lead directly to implementation. Synthesis is considerably harder for LSCs than for MSCs, and we tackle it by de ning consistency, showing that an entire LSC speci cation is consistent i it is satis able by a state-based object system, and then synthesizing a satisfying system as a collection of nite state machines or statecharts. 1

Citations