Most people associate Open ESB with enabling SOA. While thats true, only a few people know that Open ESB also enables Event-Driven Architectures (EDA)! The Intelligent Event Processor, or IEP is the component that does this. IEP is an open source Complex Event Processing (CEP) and Event Stream Processing (ESP) engine. Go check it out https://open-esb.dev.java.net/IEPSE.html"
Rise of CEP in OpenESB