Toward modular concurrency control for object-oriented distributed systems

Object-based distributed systems are intended to merge the benefits of both object-based languages and distribution. To make such systems useful, it is, however, necessary to extend the basic object model so that it can permit the expression of distribution related aspects. The author discusses the issues raised by designing transaction concurrency control within an object-oriented distributed system. He proposes an original approach based on conditions bound to each object operation. These conditions allow to express various concurrency control policies, e.g., pessimistic or optimistic, all in an orthogonal way to the serialization protocol. By confining the concurrency control code within dedicated conditions, the author enhances both encapsulation and inheritance