Guiding Service Composition in a Visual Service Creation Environment

Current Web service composition languages like WS-BPEL require in-depth knowledge of these languages by the service composition designers. In this paper we present a high-level, visual service creation environment (SCE). This SCE provides service composition templates, verification of compatibility and guidelines, and advanced separation of concerns through aspect-oriented software development. Composition templates are abstract descriptions of reusable compositions containing several placeholders for services. Services are verified to be compatible with the composition template when a service is mapped onto a composition template's placeholder. Composition guidelines such as QoS constraints can be added to the SCE and verified. The modularization of crosscutting concerns is supported by the SCE through the general-purpose Padus aspect-oriented programming language and the possibility to add concern-specific languages on top of Padus. The SCE generates the appropriate WS-BPEL processes given a complete and verified service composition