Flexibility as a Service
The lack of flexibility is often seen as an inhibitor for the successful application of workflow technology. Many researchers have proposed different ways of addressing this problem and some of these ideas have been implemented in commercial systems. However, a "one size fits all" approach is likely to fail because, depending on the situation (i.e., characteristics of processes and people involved), different types of flexibility are needed. In fact within a single process/organisation varying degrees of flexibility may be required, e.g., the front-office part of the process may require more flexibility while the back-office part requires more control. This triggers the question whether different styles of flexibility can be mixed and integrated into one system. This paper proposes the Flexibility as a Service (FAAS) approach which is inspired by the Service Oriented Architecture (SOA) and our taxonomy of flexibility. Activities in the process are linked to services. Different services may implement the corresponding activities using different workflow languages. This way different styles of modelling may be mixed and nested in any way appropriate. This paper demonstrates the FAAS approach using the Yawl, Declare, and Worklet services.