Using events to build distributed applications

Abstract

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 non-deterministic finite state machines. Initial experience with this prototype is encouraging.