Specification of composite objects based on the ODP Reference Model

In this paper, we describe our experience in using the RM-ODP to specify composite objects. The concept of a composite object as defined in RM-ODP does not take into account its dynamic structure as well as the classification of its properties into inherent, aggregate and emergent properties. To make this possible, we have to complement the description of composite objects with explicit contracts involving the composite object and its components. This interpretation of composite objects in terms of ODP concepts is technically sound. It allows a clean definition of the structure, the inherent and aggregate properties of the composite object. However, this approach is conceptually questionable since its guiding philosophy is based on ignoring the distinction between composition and interconnection of objects. This observation is grounded on the usage of contracts for defining significant aspects of object composition. We come out with the same conclusion when experimenting the description of composite objects using Darwin. What these experiments show is that we still have to rely on the concept of interconnection of objects to define the semantics of composition of objects.