Constructing Systems as Object Communities

We give a survey of concepts for system specification and design based on the viewpoint that a system is a community of objects. Objects are self-contained units of structure and behavior capable of operating independently and cooperating concurrently. Our approach integrates concepts from semantic data mod-eling and concurrent processes, adopting structuring principles partly developed in the framework of object-orientation and partly in that of abstract data types. A theory of object specification based on temporal logic is briefly outlined.