SAMOA: framework for synchronisation augmented microprotocol approach

We address programming abstractions for building pro- tocols from smaller, reusable microprotocols. The existing protocol frameworks, such as Appia and Cactus, either re- strict the amount of concurrency between microprotocols, or depend on the programmer, who should implement all the necessary synchronisation using standard language fa- cilities. We develop J-SAMOA: a framework for a Synchro- nisation Augmented Microprotocol Approach in Java. It has been designed to allow concurrent protocols to be expressed without explicit low-level synchronisation, thus making pro- gramming easier and less error-prone. In this paper, we describe versioning concurrency control algorithms. They are used by the runtime system of our framework to guaran- tee that the concurrent execution of a protocol is equivalent to a serial execution of its microprotocols. This guarantee, called the isolation property, ensures consistency of session or message-specific data maintained by microprotocols.