Using Cohesion and Coupling for Software Remodularization

Abstract

Refactoring and, in particular, remodularization operations can be performed to repair the design of a software system and remove the erosion caused by software evolution. Various approaches have been proposed to support developers during the remodularization of a software system. Most of these approaches are based on the underlying assumption that developers pursue an optimal balance between cohesion and coupling when modularizing the classes of their systems. Thus, a remodularization recommender proposes a solution that implicitly provides a (near) optimal balance between such quality attributes. However, there is still no empirical evidence that such a balance is the desideratum by developers. This article aims at analyzing both objectively and subjectively the aforementioned phenomenon. Specifically, we present the results of (1) a large study analyzing the modularization quality, in terms of package cohesion and coupling, of 100 open-source systems, and (2) a survey conducted with 29 developers aimed at understanding the driving factors they consider when performing modularization tasks. The results achieved have been used to distill a set of lessons learned that might be considered to design more effective remodularization recommenders.

The Scent of a Smell: An Extensive Comparison Between Textual and Structural Smells

“…As a consequence, accurate refactoring operations can be derived more quickly. Our findings confirm that software metrics are not the unique source of information that developers use to evaluate the quality of source code [20], [96], [21]. The results achieved represent a call to arms for researchers and practitioners to investigate the human's perspective for building a new generation of code smell detectors and refactoring tools.…”

An Empirical Study of Cohesion and Coupling: Balancing Optimization and Disruption

“…Recent studies reported quantitative and qualitative assessments of these metrics by investigating open source systems and interviewing developers [11] [53]. As previously mentioned, MQ is the most used quality metric in search based re-modularisation (see Table 1), yet evidence that software systems respect this metric is scarce.…”

“…As argued in a recent work by Candela et al [11], a modular level disruption metric, such as MoJoFM, better describes the "mental model" developers have of their systems. Therefore, we draw inspiration from the study performed by Candela et al, and adopt a disruption measurement that is based on the widely used [11] …”

“…Therefore, we draw inspiration from the study performed by Candela et al, and adopt a disruption measurement that is based on the widely used [11] …”

“…However, despite more than 30 publications on search based modularisation, few studies [13] [11] have performed an evaluation of the disruptive effects that automated modular improvement may cause on the original modular structure of the software systems under study. A thorough study of the disruption caused by modular restructuring is needed, because there is evidence that software engineers tend to resist structural and architectural improvement in favour of similarity and familiarity [57].…”