Composing Non-functional Concerns in Web Services

Support for non-functional concerns (NFC) is essential for the success and adoption of web services. This support encompasses two aspects: the specification of NFCs and their realization. However, state-of-the-art works offer only limited support for these aspects. This is especially true for the composition of multiple non-functional concerns with one web service, which is a highly complex task. It is complex because specific knowledge from different domains is required, as well as an understanding of the interdependencies between non-orthogonal NFCs. In this paper, we present an approach and a toolset for the specification and realization of the composition of multiple NFCs in web services. We also present a well-defined process involving different roles and we introduce graphical modeling notations for specifying non-functional requirements, actions realizing the requirements, action compositions and the mapping of actions to web services. These specification models are used for the generation of code that realizes the NFCs.