Web Service Composition with O’GRAPE and OSIRIS
Roger Weber, Christoph Schuler, Patrick Neukomm, Heiko Schuldt, Hans-Jörg Schek
Proceedings of the 29th International Conference on Very Large Databases (VLDB'2003)
Services are well known building blocks in modern information systems. Technologies and standards like XML, SOAP (Simple Object Access Protocol), and WSDL (Web Service Description Language) provide a simple means to describe these services and to make them accessible to a large community in a distributed environment. Yet, the full potential of web services becomes only apparent if we can combine several service invocations in a well-defined order and with well-designed execution guarantees to establish even more powerful composite services. Among others, processes provide a simple mechanism to compose services. A process defines the logical dependencies between independent services by specifying an invocation order (control flow) as well as rules for the transfer of data items between different invocations (data flow). In addition and following the model of transactional processes, we can define the transactional behavior and execution guarantees to ensure a correct execution of processes in case of concurrency and failures. An infrastructure for transactional processes has to support all these run-time features. Furthermore, a graphical process modeling tool should support the specification of all these features. An important aspect is that such a modeling tool is transparently integrated into the process management environment.