Programming abstractions for content-based publish/subscribe in object-oriented languages

Abstract

Asynchronous event-based communication facilitates loose coupling and eases the integration of autonomous, heterogeneous components into complex systems. Many middleware platforms for event-based communication follow the publish/subscribe paradigm. Despite the usefulness of such systems, their programming support is currently limited. Usually, publish/subscribe systems only exhibit low-level programming abstractions to application developers. In this paper we investigate programming abstractions for content-based publish/subscribe middleware in object-oriented languages, how they can be integrated in applications, and their implications on middleware implementation. We focus on the definition of filters and their implementation, the handling of notifications and meta-data, and programming support for composite events. We have implemented the presented approach for our content-based publish/subscribe middleware REBECA. Keywords: content-based publish/subscribe, middleware, programming abstractions, composite events.