Composing and coordinating transactional Web services

Composite applications leveraging the functionalities offered by Web services are today the underpinnings of enterprise computing. However, current Web services composition systems make only use of functional requirements in the selection process of component Web services while transactional consistency is a crucial parameter of most business applications. The transactional challenges raised by the composition of Web services are twofold: integrating relaxed atomicity constraints at both design and composition time and coping with the dynamicity introduced by the service oriented computing paradigm. This chapter proposes a new process to automate the design of transactional composite Web services. This solution for Web services composition does not take into account functional requirements only but also transactional ones based on the Acceptable Termination States model. The resulting composite Web service is compliant with the consistency requirements expressed by business application designers and its execution can easily be coordinated using the coordination rules provided as an outcome of the authors' approach. An implementation of these theoretical results augmenting an OWL-S matchmaker is further detailed as a proof of concept.