William R. Cook, Sourabh Patwardhan, Jayadev Misra. Workflow Patterns in Orc. In Paolo Ciancarini, Herbert Wiklicky, editors, Coordination Models and Languages, 8th International Conference, COORDINATION 2006, Bologna, Italy, June 14-16, 2006, Proceedings. Volume 4038 of Lecture Notes in Computer Science, pages 82-96, Springer, 2006. [doi]
Van der Aalst recently proposed a set of workflow patterns to characterize the kinds of control flow that appear frequently in workflow processes. These patterns are useful for evaluating the capabilities of workflow systems and models. In this paper we provide implementations of the workflow patterns in Orc, a new process calculus for orchestrating wide-area computations. A key feature of the Orc implementations is that they are expressed as definitions that can be reused as needed.