MODE: A Java-like Environment for Experimenting Mobility Policies

The wide acceptance of object-oriented environments and proposals has renewed interest in all the class inheritance related issues; in particular its implementation in distributed architectures. The paper focuses on how the inheritance relationship could impact on (possibly heterogeneous) distributed systems that do not assume co-residence of objects and their classes / superclasses. In these systems, the object computation requires either to move / copy the (class) inheritance graph or to move the objects themselves. Several policies are feasible, depending on the decisions about moving / copying the data / code part of objects, and also depending on when these actions should take place. The paper presents MODE, an environment that, other than being very useful in promoting collaborative work, allows to assess and compare different mobility policies. Java has been adopted as a common underlying language, able to confer portability to all modern and widely used architectures.