Executable and Symbolic Conformance Tests for Implementation Models

Following the Model-Driven Architecture (MDA), a system description consists of several models, i.e. views of the system. This paper is concerned with formal conformance tests between different models. It stresses the need for formal semantical foundations of all languages that are used to express models. In particular, we classify conformance tests for implementation models. The Model-Driven Architecture (MDA) [14,2] is the new strategy of the OMG to maintain the whole lifecycle of a system. A system is specified by a collection of several views, which concentrate on certain aspects and hides all non-relevant details. In the terminology of MDA a view is called model. Different kinds of models are usually expressed in different suitable languages. The implementation of a system is seen as just one model among others. MDA does not stipulate the usage of particular languages to express particular models. However, implementation models are usually expressed in terms of a programming language. Especially in the development phase of a system, periodical checks on the consistency of all models are crucial. MDA calls this activity conformance test between two or more models. In this paper, we focus on conformance tests which can be performed by a machine. Obviously, such conformance tests presuppose a formal underpinning of all languages used to express the involved models. We concentrate on the conformance test between the implementation model and a single additional model. For practical reasons, we assume Java to be the language for expressing the implementation model. The semantics of Java was originally defined in [3]. Due to its informal nature, [3] cannot be used directly for machine-based conformance tests. Instead, another representation of Java’s semantics has to be chosen. We discuss two representations, and investigate the influence of that choice on the nature of the corresponding conformance tests. Java Semantics Given by a Compiler A pragmatic and popular approach defines the semantics of Java by the actual behaviour of programs on a machine. Adopting this approach for the semantical foundation of implementation models means to define implementation models in terms of the J.-M. Bruel and Z. Bellahsène (Eds.): OOIS 2002 Workshops, LNCS 2426, pp. 231–234, 2002. c © Springer-Verlag Berlin Heidelberg 2002