Extending conventional languages by distributed/concurrent exception resolution

The state of art in handling and resolving concurrent exceptions is discuss ed and a brief outline of all research in this area is given. Our intention is to demonstrate that exception resolution is a very useful concept which facilitates joint forward error recovery in concurrent and distributed sys tems. To do this, several new arguments are considered. We understand resol ution as reaching an agreement among cooperating participants of an atomic action. It is provided by the underlying system to make it unified and less error prone, which is important for forward error recovery, complex by nat ure. We classify atomic action schemes into asynchronous and synchronous on es and discuss exception handling for schemes of both kinds. The paper also deals with introducing atomic action schemes based on exception resolution into existing concurrent and distributed languages, which usually have onl y local exceptions. We outline the basic approach and demonstrate its appli cability by showing how exception resolution can be used in Ada 83, Ada 95 (for both concurrent and distributed systems) and Java. A discussion of way s to make this concept more object-oriented and, with the help of reflectio n, more flexible and useful, concludes the paper. (C) 2000 Elsevier Science B.V. All rights reserved.