An Animation Tool for Supporting Specification-Based Software Architectures

One of the important issues in supporting specification-based software architectures is how to verify that formal specifications of a software system satisfy liveness, safety and timing constraints, and are consistent and complete with regard to user requirements. Animation has been proposed as one of the techniques for achieving this goal. This article presents a practical approach and a tool to animating object-oriented formal specifications written in the language Z. Implemented in Prolog, the tool handles inheritance, object identity, invariant and precondition checks, both the logical and the sequential method composition, and nondeterminism. It offers a solution to the mutable state problem. The merits of applying the tool to validating formal specifications are demonstrated in a case study. Animation is shown to be helpful in gaining the insight on how the specified system works, in validating the conformance of the formal specification to particular user requirements, as well as in "debugging" the formal specification.