This paper describes the design and the prototype implementation of a middleware, called Java Signal Core Layer (jscl), for coordinating distributed services. jscl supports the coordination of distributed services by exploiting an event notification paradigm. The design and the implementation of jscl has been inspired and driven by its formal specification given as a process calculus, the Signal Calculus (sc). At the experimental level JSCL has been exploited to implement Long Running Transactions (LRTs).
Research partially supported by the EU, within the FET GC Project IST-2005-16004 Sensoria, and FIRB Project TOCAI.IT.