Rule-Based Synchronization of Process Activities

Synchronization of running process instances has been identified as major challenge in literature and practice. Although process instances are, for example, often required to share resources such as printers or centrifuges, the necessary instance synchronization is not supported by most process engines. While existing (scarcely supported) patterns deal with the intra-process synchronization of activities, a model for a more generic synchronization mechanism is still missing. The contribution of this paper is two-fold. (1) We introduce a generic model to describe the state transitions of process instances at runtime, and based on this model (2) define a subscription based event / voting mechanism that enables arbitrary synchronization within and between running instances. In order to demonstrate the validity of our approach, we will conduct an extensive evaluation against existing synchronization patterns, as well as describe a generic rule engine prototype that implements the presented approach.