Implied Scenario Detection in the Presence of Behaviour Constraints
Sebastián Uchitel, Jeff Kramer, Jeff Magee · Electronic Notes in Theoretical Computer Science · 2002
Scenario-based specifications describe how independent components interact to provide system level behaviour. The specified system decomposition and system behaviour can give rise to implied scenarios, which are the result of specifying the global behaviour of a system that will be implemented component-wise. The existence of implied scenarios is an indication that further validation with stakeholders must be done. An implied scenario can be accepted or rejected by stakeholders indicating that the implied scenario is acceptable system behaviour or a situation that should be avoided. In consequence, implied scenarios can be used to iteratively drive requirement elicitation. However, in order to do so, we must be capable of detecting implied scenarios in the presence of rejected implied scenarios, in other words in the presence of behaviour constraints. The contribution of this paper is a technique for detecting implied scenarios in message sequence chart (MSC) specifications that can be used in conjunction with behaviour constraints. The technique is based on building a Coordinator component that forces system components to follow the same sequence of basic MSCs as they go through a high-level MSC. The result is a model that behaves as specified in the MSC but does not comply with the MSC architecture. The resulting model is not a proposed implementation, rather a precise model of specified behaviour that can be used in combination with constrained implementation models to detect further implied scenarios.