Monitor-Oriented Compensation Programming Through Compensating Automata

Abstract

Compensations have been used for decades in areas such as flow management systems, long-lived transactions and more recently in the service-oriented architecture. Since compensations enable the logical reversal of past actions, by their nature they crosscut other programming concerns. Thus, intertwining compensations with the rest of the system not only makes programs less well-structured, but also limits the expressivity of compensations due to the tight coupling with the system's behaviour.

To separate compensation concerns from the normal system behaviour, we propose compensating automata, a graphical specification language dedicated to compensation programming. Compensating automata are subsequently employed in a monitor-oriented fashion to program compensations without cluttering the actual system implementation. This approach is shown applicable to a complex case study which existing compensation approaches have difficulty handling.