A Flexible and Extensible Component-Oriented Middleware for Creating Context-Aware Applications

In this paper, we describe a middleware system, called J2CS (Java 2 Context Service), that provides support to most of the tasks involved in designing context-aware applications in Java. The J2CS system can be classified as a lightweighted, flexible, extensible and component-oriented middleware. In the proposed platform, containers manage the life cycle of components called contextlets which are used to infer high-level events from. low-level sensed data. Containers are also in charge of handling communication details with sensors and other sources of context information. In this paper, we discuss the software architecture, the programming interface, the run-time performance and the implementation of J2CS. We also present some examples of context-aware applications based on the proposed middleware