Event-based Distributed Workflow Execution with EVE

In event-driven workflow execution, events and event-condition-action rules are the fundamental metaphors for defining and enforcing workflow logic. Processing entities enact workflows by reacting to and generating new events. The foundation on events also eases the integration of processing entities into coherent systems. In this paper, we present an event engine, called EVE, implementing event-driven execution of distributed workflows. Its functionality includes event registration, detection and management, as well as event notification to distributed, autonomous, reactive software components which represent workflow processing entities. EVE also maintains a history of all event occurrences in the system used for the monitoring and analysis of executing workflows. We describe the distributed, multi-server, multi-client architecture of EVE and illustrate its usage for workflow execution