Integration of Transaction Management in Web Service Orchestrations

This thesis tries to spur on transaction–oriented processing in distributed Web service systems, particularly in Web service orchestrations that implement virtual enterprises. For this purpose, existing scientific work in the area of advanced transaction semantics is analyzed in terms of its applicability in Web service systems. Moreover, the thesis examines prominent existing proposals for transactional Web service systems. These proposals are quite alike and certain shared deficits, which may be the reason for their minor success, are pointed out. The main part of the thesis specifies a new approach for distributed transactional Web service systems: TWSO – Transactional Web Service Orchestrations. This approach is based on a programmatic paradigm, as also normally used in traditional transaction systems. Thus, a clear and well–known usage pattern is presented. Complex and arbitrary transactions semantics can be implemented by using concepts as follows. A set of transaction primitives, that is appropriate for Web service needs, is provided and it is possible to coordinate multiple concurrent transactions. TWSO concepts can be integrated with arbitrary Web service orchestration technologies. The thesis contains integration proposals for XPDL and Java Web service orchestrations. To evaluate the TWSO approach on the basis of certain predefined criteria, a scenario, which stems from a real–world project in the tourism domain, is used. It is implemented using a prototypical TWSO system. Evaluation results show that TWSO satisfies the postulated criteria.