A framework supporting dynamic workflow interoperation

Abstract

When a workflow process spans to multiple organizations, subprocess task model is an efficient way of representing remote services of other systems. The subprocess task usually represents a single service in conventional workflows. However, if a subprocess task comprises multiple services, and the number of services and the execution flow of the services cannot be decided until run-time, conventional ways of workflow design is not proper to handle such situations efficiently. All potentially reachable paths should be known at process build time in conventional workflow design. However, such an assumption does not always hold in real situations. In this paper, we propose a multi-subprocess task based framework for dynamic workflow interoperations. In the framework, we develop the multi-subprocess task model to handle a subprocess composed of multiple services that are unknown at process build time. In this paper, we also define and implement four components to support the dynamic workflow interoperation: Workflow engine, Adapter, Service Interface Repositories (SIRs), and XML messages. Adapter and SIR make a local WfMS transparent to the location and platform of the interoperating WfMSs by encapsulating external subprocesses and superprocesses. When an example scenario is implemented and evaluated in the proposed framework, the advantages of the framework are obvious in terms of automaticity, adaptability, and efficiency.