The most recent service composition approaches rely on the mechanism, which involves scalable and decentralized execution of services. Although some formal tools have been used to this effect, they are influenced by the standard of web service orchestration and choreography based mainly on workflow languages or notation. In this paper, we describe the formal semantics of a novel service composition language through which the services are declaratively composed and executed following a peer-to-peer paradigm. The proposed language named GSLang is inspired by the GAG (Guarded Attribute Grammars) model that has been defined for the modeling collaborative systems. Picalculus is used to define the basic elements of the language and its operational semantics. Then its properties are highlighted through a case study.

The emergence of BPML (Business Process Modeling Language) has favored the development of languages for the composition of services. Process-oriented approaches produce imperative languages, which are rigid to change at run-time because they focus on how the processes should be built. Despite the fact that semantics is introduced in languages to increase their flexibility, dynamism is limited to find services that have disappeared or become defective. They do not offer the possibility to adapt the composite service to execution. Although rules-based languages were introduced, they remain very much dependent on the BPML which is the underlying technology. This article proposes the specification of a rule-based declarative language for the composition of services. It consists of the syntactic categories which make up the concepts of the language and a formal description of the operational semantics that highlights the dynamism, the flexibility and the adaptability of the language thus defined. This paper also presents a verification framework made of a formal aspect and a toolset. The verification framework translates service specifications into Promela for model checking. Then, a validation framework is proposed that translates the verified specifications to the operational system. Finally, a case study is presented.

The layered software architecture is the model commonly adopted for the development of information systems since it favors the modularity and the scalability of the systems. On the other hand, the emergence of model engineering aims to raise the level of abstraction to allow developers to reason on models, and less in code. The research question is to combine the two approaches to facilitate the work of developers. The proposal resulting from this study is based on a set of concepts defined using the UML profiles. These concepts include services, business components, and data persistence. Then the Kruchten model is adopted to represent the development cycle according to several views, each view being represented by UML diagrams derived from the previously defined profiles. Finally, rules are available for checking inter-view consistency, from refinement to code generation. The result is a step towards the definition of a domain specific ADL and a development process as much as it includes the expected characteristics of such a language, namely: the fundamental concepts, the support tools and the multiview development.