Getting 'whole Picture' Behavior in a Use Case Model

Although widely used, traditional use case modeling does not provide explicit means which could be easily used for capturing and testing behavior compliance of the entities involved in a particular use case model. Specifically, a use case model (a set of use cases) related to a system under design provides neither an explicit abstraction to capture the “whole picture” of the behavior of the system, nor to cover the interactions of subsystems and internal actors with the parent system. With the aim to allow for reasoning on the behavior, the paper introduces a simple formal model Generic UC View which identifies important abstractions and the relations upon them which target the goal. Among them, the concept of use case expression is the base for the desired reasoning on whether the behavior of an entity (such as an agent, a subsystem or a software component) complies with the composed behavior of its sub-entities, and the behavior on the communication links of two neighboring entities is compliant. As a proof of the concept, an instance of use case expressions, pro-cases is introduced. Based on behavior protocols [20], pro-cases can be checked for compliance via an already existing verifier. As pro-cases’ syntax is simple, resembling regular-expressions, there are simple guidelines for transforming a use case written in classical textual form (based on a template) into a pro-case.