Petri Nets Based Formalization of Textual Use Cases

A Use Case is a specification of interactions involving a system and external actors of that system. The intuitive, user centered nature of textual use cases is one of the reasons for the success of the use case approach. A certain level of formalization is however needed to automate use case based system development, including tasks such as model synthesis, verification and validation. In this paper, a formalization of textual use cases is proposed. At the syntactic-level, an UML metamodel and a restricted-form of natural language are defined for use case description. Use cases execution semantics are proposed as a set of Mapping Rules from well-formed use cases to Basic Petri nets. The semantics consider use cases sequencing constraints defined at the syntactic-level. The proposed formalization serves as a basis for state-model synthesis from use cases. UML activity diagrams are generated to capture use cases sequencing and UML StateCharts to capture event flows within use cases