Workflow: A Language for Composing Web Services

The introduction of Web Services has a profound impact on component models. The interaction processes behind a service become integral part of the component type, and as such formally described and automatically manageable. Workflow emerges as the reference model for the description of interaction processes associated to individual web services. In the DySCo (Dynamic Service Composition) project, we investigate the use of workflow for both the modelling and implementation of composite solutions based on web services. Key aspect of DySCo is the separation between composition and coordination logic. In this paper, we discuss the composition model defined in DySCo, and a technology framework to enforce it.