Using events to build large scale distributed applications

We have extended an Interface Definition Language to handle event registration and notification. Clients register interest in specified classes of events, and servers then notify them of any occurrence asynchronously. Event occurrences are identified by parameters which conform to IDL typing constraints and can therefore be used in synchronous method invocations. Methods to handle registration and notification are generic and can be inherited by objects of any class: as a by-product of IDL processing the stubs to handle event creation and decoding are generated automatically. We have implemented a prototype composite event recogniser based on nested finite state machines and have defined an event algebra and language to specify composite events.The approach is inherently scalable in that only events in which an interest has been registered are notified. Alternative approaches lead to polling, mining for event data or being flooded with superfluous events.