Formalizing Liveness-Enriched Sequence Diagrams Using ASMs

Abstract

Abstract. In UML 2.0 sequence diagrams have been considerably extended, influenced by Live Sequence Charts (LSCs), a very expressive extension of Message Sequence Charts (MSC) with liveness. Nonetheless, fundamental liveness properties can still not be expressed in the new sequence diagrams. In recent work, we have proposed to solve this by enriching sequence diagrams with a simple but powerful Object Constraint Language (OCL) template for liveness. In this paper, we show how to formalize our liveness-enriched sequence diagrams using Abstract State Machines. Sequence diagrams still have several open problems. For example, the semantics of some of the newly introduced operators is ambiguous, and it is not clear how they can be used or combined with other operators. We address some of these issues in the paper. Finally, a further advantage of using ASMs as a semantic model concerns synthesis. It is our ultimate goal to be able to synthesise automatically a state-based object system from our richer sequence diagrams. ASMs are a state-based and operational formalism which therefore eases this task considerably.

A value-oriented specification for weak sequencing validation

“…Process algebras appear as the appropriate formalism for the specification of weak sequencing in UML 2 interactions [8,14], but they fail to appropriately translate the concurrency specified within the InteractionFragments [1]. On the other hand, trueconcurrency-based formalisms ignore the standard interpretation and introduce synchronization on entering and exiting fragments [7,9,10,11,14]. Such an interpretation allows reducing the described partial orders of events, and then makes properties easier to check.…”

The many meanings of UML 2 Sequence Diagrams: a survey

“…In [4], the authors defined a semantics to this livenessenriched Sequence Diagrams using abstract state machines (ASM). Locations are associated with each important point on the Lifelines.…”

Relating computer systems to sequence diagrams: the impact of underspecification and inherent nondeterminism

“…In [CF04,CF05], Cavarra and Küster-FIlipe present an operational semantics for UML 2.x sequence diagrams inspired by LSC. Liveness properties are expressed by adding OCL (Object Constraint Language [OMG06]) constraints to the sequence diagrams.…”