An External Client-Based Approach for the Extract Class Refactoring: A Theoretical Model and an Empirical Approach

Abstract

A commonly observed ambiguity of a class is simply a reflection of multiple methods’ implementation within an individual class. The process of Extract Class refactoring is, therefore, used to separate the different responsibilities of a class into different classes. A major limitation in existing approaches of the Extract Class refactoring is based on factors that are internal to the class, i.e., structural and semantic relationships between methods, in order to identify and separate the responsibilities of the class which are inadequate in many cases. Thus, we propose a novel approach that exploits the clients of the class to support the Extract Class refactoring. The importance of this approach lies in its usefulness to support existing approaches since it involves factors external to the class, i.e., the clients. Moreover, an extensive empirical evaluation is presented to support the proposed method through the utilization of real classes selected from two open source systems. The result shows the potential of our proposed approach and usefulness that leads to an improvement in the quality of the considered classes.