Real-Time Complex Event Processing using Concurrent Reactive Objects

Service Oriented Architectures (SOAs) and Complex Event Processing (CEP) are established technologies in the area of business automation. In combination, SOA and CEP allow for event centric management and processing of information in complex distributed systems. Whereas systems for process monitoring and control traditionally have been deployed using dedicated buses and proprietary (often scan-based) protocols, a recent trend in process automation is towards adopting open Internet-based technologies. This trend is driven by the increasing number and capabilities of devices used for monitoring and control. In such setting, SOA enabled devices can operate both as producers and consumers of (complex) events. To this end a lightweight CEP engine has recently been proposed, defining the translation of a subset of CEDR clauses into Concurrent Reactive Objects (CROs). In this paper we extend the proposed mechanism to incorporate non-deterministic execution, reoccurring events, overlapping timing windows and real-time properties. The extension allows timing properties to be either explicit, given as the deadline for a CEP query, or being derived from subqueries. Additionally, the described extensions form a foundation for future studies of timing properties for query processing and communication, in distributed heterogeneous systems. As a proof of concept, we demonstrate how the proposed mechanism can be encoded in the CRO based Timber language.