Towards Complex Event Aware Services as Part of SOA

Abstract

Complex Event Processing (CEP) has so far been implemented in technology and vendor-specific manner. Introducing CEP concepts to the Service Oriented Architecture (SOA) provides an opportunity to enhance the capabilities of SOA. We define a model that supports the CEP usage in SOA where the actual pattern recognition can be done by any external CEP Engine. We define a new service type - a Complex Event Aware (CEA) service that automatically reacts to complex events specified in its interface. The proposed model includes a CEP Manager that provides centralized management of complex events and, through its pluggable adapters, communicates with CEA Services and CEP Engines. It includes a CEP Registry and a CEP Repository enabling versioning and reuse of complex event types, and a CEP Dispatcher providing publish/subscribe communication framework. We design a generic XML schema for abstract complex event type definition and propose new extensions for Service Component Architecture (SCA) and Web Services Description Language (WSDL) specifications, which enable definitions of complex event types and complex event sinks in the CEA Service interface. As a proof-of-concept we develop a prototype implementation for the largest national telecommunication provider and in the real-world scenario show advantages of the proposed model.