Data-driven adaptation for smart sessions

Abstract

This paper presents a formal framework of self-adaptation for multiparty sessions. The adaptation function contains the dynamic evolution policy, by prescribing how the session needs to reconfigure itself, based on critical changes in global data. A global type prescribes the overall communication choreography; its projections onto participants generate the monitors, which set-up the communication protocols. The key technical novelty of the calculus is the parallel operator for building global types and monitors, which allows the adaptation procedure to be rather flexible. The smart session is able to minimise its adaptation, by partially reconfiguring some of the communications and leaving all others unchanged, in case a part of the whole behaviour only needs to be modified. Furthermore, new participants can be added and/or some of the old participants can be removed. As a main result, we prove that this adaptation mechanism is safe, in order to guarantee that the communications will continue to evolve in a correct way after reconfiguration.