FLEXIBLE SPECIFICATION OF INTEROPERABLE TRANSACTIONS

Interoperable transactions differ from traditional transactions in the ir longer time-span and the central place of communication and interac tion. Specification of interoperable transactions should be flexible i n the sense that the scheduling aspects for a transaction should be de coupled from the communication aspects as well as being reactive to fa ilures. During the execution of an interoperable transaction, steps ha ve to be rolled back, or compensated, and sometimes different alternat ives must be tried and negotiated to fulfil the given task instead of aborting the whole transaction. In this paper, we propose a separation of the specification of communication aspects, the scheduling aspects and the failures aspects of interoperable transactions to achieve ext ra flexibility. Of particular importance is the introduction of contra cts for specifying and managing failures in interoperable systems and Tasks for managing the execution strategies of interoperable transacti ons.