Creating abstract superclasses by refactoring

Abstract

This paper focuses on object-oriented programming and one kind of structure-improving transformation (refactoring) that is unique to object-oriented programming: finding abstract superclasses. We decompose the operation of finding an abstract superclass into a set of refactoring steps, and provide examples. We discuss techniques that can automate or automatically support these steps. We also consider some of the conditions that must be satisfied to perform a refactoring safely; sometimes to satisfy these conditions other refactorings must first be applied.