JavaSpaces™ Principles, Patterns, and Practice

3.3. Unordered Structures

Unordered data structures don't occur often in nondistributed programming, but they are widely used in space-based programming. An unordered distributed data structure consists of a collection of objects. Unlike an ordered collection, such as an array where we can address a particular element and read its value or change it, an unordered structure allows us to typically perform two operations: “put” and “get.” The “put” operation allows you to add a new object to a collection, while “get” returns an arbitrary object from the collection. Because these data structures have no internal order, there is no criteria for returning any one object over any other, so an arbitrary one is returned.

Typically most unordered data ...