FOCAS: An Enginering Environment for Service-Based Applications

Service composition is an important topic, but so far addressed from a technical and low level perspective. The issue is not (too much) the orchestration formalism, but rather the engineering issues related to the many concerns that must be combined, to the technical complexity, to the heterogeneity and incompatibilities between available services, and the low level formalism and tools. The paper presents FOCAS, a full fledge environment that targets the different categories of stakeholders involved in the design, development, and maintenance of a service-based application. FOCAS first separates the different concerns, both functional and non functional, that made up a service-based application; second, it separates different levels of abstraction, and third it establishes links and mediations between these concerns and levels of abstraction. The paper presents FOCAS its principles, implementation and its evaluation.