An Analysis of Formal Languages for Dynamic Adaptation

The service-oriented computing paradigm is in widespread use for adaptive systems that face changing conditions in their operational environment as well as the integration of new services. In many domains, adaptations may occur dynamically and in real-time, using services from heterogeneous, possibly unknown sources. This motivates a need to ensure the correct behaviour of the adapted system, and its continuing compliance to time bounds. The complexity of dynamic adaptation (DA) is significant, but unfortunately currently not well understood or formally specified. Formal methods are an attractive option for solving this problem as they provide a means to precisely model a software system. There are many formal languages targeted to different domains, and in this paper, we present the results of our analysis of three languages as potential candidates for modelling our time-constrained DA problem. In particular, we selected JOLIE, PiDuce and COWS for analysis, as they are targeted towards service-based systems and each provide means to model at least some of our requirements. Our results illustrate the strengths and limitations of each, and justify our selection of COWS as the best-fit, though limited, language for our purposes.