A language framework for multi-object coordination

Abstract

We have developed language support for the expression of multi-object coordination. In our language, coordination patterns can be specified abstractly, independent of the protocols needed to implement them. Coordination patterns are expressed in the form of constraints that restrict invocation of a group of objects. Constraints are defined in terms of the interface of the objects being invoked rather than their internal representation. Invocation constraints enforce properties, such as temporal ordering and atomicity, that hold when invoking objects in a group. A constraint can permanently control access to a group of objects, thereby expressing an inherent access restriction associated with the group. Furthermore, a constraint can temporarily enforce access restrictions during the activity of individual clients. In that way, constraints can express specialized access schemes required by a group of clients.