Querying composite events for reactivity on the web

Abstract

Reactivity, the ability to detect events and respond to them automatically through reactive programs, is a key requirement in many present-day information systems. Work on Web Services reflects the need for support of reactivity on a higher abstraction level than just message exchange by HTTP. This article presents the composite event query facilities of the reactive rule-based programming language XChange. Composite events are important in the dynamic world of the Web where applications, or Web Services, that have not been engineered together are composed and have to cooperate by exchanging event messages. © Springer-Verlag Berlin Heidelberg 2006.