Data Flow-based Validation of Web Services Compositions: Perspectives and Examples

Composition of Web Services (WSs) is anticipated as the future standard way to dynamically build distributed applications, and hence their verification and validation is attracting great attention. The standardization of BPEL as a composition language and of WSDL as a WS interface definition language has led researchers to investigate verification and validation techniques mainly focusing on the sequence of events in the composition, while minor attention has been paid to the validation of the data flow exchange. In this chapter we study the potential of using data flow modelling for testing composite WSs. After an exhaustive exploration of the issues on testing based on data-related bmodels, we schematically settle future research issues on the perspectives opened by data flow-based validation and present examples for some of them, illustrated on the case study of a composite WS that we have developed, the Virtual Scientific Book Store.