Formalizing Collaboration Goal Sequences for Service Choreography

Methods for service specification should be simple and intuitive. At the same time they should be precise and allow early validation and detection of inconsistencies. UML 2.0 collaborations enable a systematic and structured way to provide overview of distributed services, and decompose cross-cutting service behaviour into features and interfaces by means of collaboration-uses. To fully take advantage of the possibilities thus opened, a way to compose (i.e. choreograph) the joint collaboration behaviour is needed. So-called collaboration goal sequences have been introduced for this purpose. They describe the behavioural composition of collaboration-uses (modeling interface behaviour and features) within a composite collaboration. In this paper we propose a formal semantics for collaboration goal sequences by means of hierarchical coloured Petri-nets (HCPNs). We then show how tools available for HCPNs can be used to automatically analyse goal sequences in order to detect implied scenarios.