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 compo-nents into complex systems. Many middleware platforms for event-based communication follow the publish/subscribe paradigm. Despite the use-fulness 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 pro-gramming 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 notifica-tions and meta-data, and programming support for composite events. We have implemented the presented approach for our content-based pub-lish/subscribe middleware Rebeca