Flat Committed Join in Join

ROBERTO BRUNI; HERNÁN MELGRATTI; UGO MONTANARI

Workshop; Proceedings of the Workshop of the COMETA Project on Computational Metamodels; 2003

Committed Join (cJoin) is an extension of Join with high-level primitives for programmingdynamic nested negotiations with compensations. In this paper we show that flat cJoinprocesses (i.e. processes without sub-negotiations) can be encoded in the ordinary Join calculusby exploiting a distributed two-phase commit protocol. In particular, we first define atype system that singles out flat processes and prove subject reduction for it. Then, we showthat all flat cJoin processes can be written in an equivalent canonical form, where a few elementarydefinition patterns are used. Finally, we show that canonical flat processes canbe implemented in Join. It is worth noting that negotiation primitives are encoded as fullydistributed agreements between all participants, thus avoiding a centralized coordinator.