The minimal design and requirements for simple event systems were developed, one for which more advanced features for complex applications can be readily built. A Grid SOAP events framework was introduced as a simple and extensible event system. This framework defines an XML-Schema for the base event type and minimal interface for event listener, making it particularly simple.
We proposed the use of event channel with lease based subscriptions and XML based remote references. Leasing helps improve the robustness in the system while developing interconnected network of event publishers (producers), channels (intermediaries) and listeners (consumers).
xEvents is an implementation of Grid SOAP events. The event system in SoapRMI has been implemented in both C++ and Java. This implementation achieves all five criteria specified earlier: simplicity, extensibility, rapid deployment and integration, interoperability, and performance. Our implementation allows direct interoperability between Java and C++, and the performance testing indicates 4500 small events per second can be sent and 1000 can be recieved per second - enough to support the identified Grid applications.