Searchbased determination of refactorings for improving the class structure of object-oriented systems

A software system’s structure degrades over time, a phe-nomenon that is known as software decay or design drift. Since the quality of the structure has major impact on the maintainability of a system, the structure has to be recon-ditioned from time to time. Even if recent advances in the fields of automated detection of bad smells and refactorings have made life easier for software engineers, this is still a very complex and resource consuming task. Search-based approaches have turned out to be helpful in aiding a software engineer to improve the subsystem struc-ture of a software system. In this paper we show that such techniques are also applicable when reconditioning the class structure of a system. We describe a novel search-based ap-proach that assists a software engineer who has to perform this task by suggesting a list of refactorings. Our approach uses an evolutionary algorithm and simulated refactorings that do not change the system’s externally visible behavior. The approach is evaluated using the open-source case study JHotDraw