Towards automated alignment of Web Services to requirements

The engineering of a web service-oriented system requires the specification of the functions that the various Web Services (WSs) should provide, before WSs are either built or selected. Being written in a service description language, the service specification instantiates concepts different than those of interest during the requirement engineering (RE): the former speaks in terms of, e.g., operations and bindings, while the latter manipulates, e.g., goals and domain assumptions. It is, however, clear that functions expected of WSs will be relevant to the stakeholders if and only if they satisfy the stakeholders' requirements. There is therefore a gap between the two specifications which must be bridged in order to ensure that the WS system is adequate w.r.t. stakeholders' requirements. This paper proposes mappings between the RE concepts and those of the WS Description Language (WSDL) and WS Level Agreement (WSLA). A working prototype is presented that implements the mappings and allows automated translation of the instances of RE concepts into instances of WSDL and WSLA concepts. The mappings and the prototype facilitate the engineering of WS systems, as fragments of WS descriptions can be generated from requirements.