Metamodel Adaptation and Model Co-adaptation

Like other software artefacts, metamodels evolve over time. We propose a transformational approach to assist metamodel evolution by stepwise adaptation. In the first part of the paper, we adopt ideas from grammar engineering to define several semanticsand instancepreservation properties in terms of metamodel relations. This part is not restricted to any metamodel formalism. In the second part, we present a library of QVT Relations for the stepwise adaptation of MOF compliant metamodels. Transformations from this library separate preservation properties. We distinguish three kinds of adaptation according to these properties; namely refactoring, construction, and destruction. Coadaptation of models is discussed with respect to instance-preservation. In most cases, co-adaptation is achieved automatically. Finally, we point out applications in the areas of metamodel design, implementation, refinement, maintenance, and recovery.