Formalising Service-Oriented Design

Service-Oriented Computing (SOC) is an emerging paradigm for developing software systems that employ services. Presently there is already much research effort in the areas of service discovery and orchestration, business process modelling, and the semantic web. While these are all important aspects for moving towards the pervasive adoption of SOC, most existing work assumes the existence of black box services, with little attention given to how such services might be developed in a systematic manner. Furthermore, a precise description of what constitutes a service-oriented system is yet to be formally defined, and the overall impact of service-orientation on the software design process is not well understood. Therefore, this work presents a formal model covering design artefacts in service-oriented systems and their structural and behavioural properties. The model promotes a better understanding of service-oriented design concepts, and in particular, enables the definition of software metrics in an unambiguous, formal manner. Defining such a model and metrics is an initial step towards deriving a comprehensive service-oriented software design methodology.