Applying Reo to Service Coordination in Long-Running Business Transactions

Ensuring transactional behavior of business processes and web service compositions is an essential issue in the area of service-oriented computing. Transactions in this context may require long periods of time to complete and must be managed using non-blocking techniques. Compensations are activities executed to preserve data integrity and eliminate the effects of a process terminated by a user or that failed to complete due to another reason. This paper presents an approach to formal modeling of long-running business transactions. Our solution is based on the channel-based exogenous coordination language Reo, which is an expressive, compositional and semantically precise design language that admits formal reasoning. We illustrate how Reo can be used for termination and compensation handling in a number of commonly-used workflow patterns, including sequential and parallel compositions, discriminator choice and concurrent flows with link dependencies.