An Analysis of Windows Workflow's Control-Flow Expressiveness

The Windows Workflow Foundation (WF) has been introduced as part of the .NET framework as a means of creating workflow-centric applications. Its intended field of application is broad, ranging from fat-client applications and web applications to enterprise application integration solutions. Unlike other approaches Windows Workflow supports two distinct approaches to workflow specification - sequential workflows and state machine workflows - which deal with fundamentally different types of business scenarios. To date there has been minimal investigation into its capabilities and limitations, especially with respect to the two different control-flow styles it offers. To remedy this, in this paper we present a rigorous analysis of Windows Workflow's ability to deal with common control-flow scenarios. As a framework for this evaluation we use the Workflow Patterns. Our analysis outlines the strength and shortcomings of Windows Workflow's control-flow expressiveness and compares it to BPEL and jBPM - two other popular approaches for the design and implementation of business processes in a service-oriented context.