Measurement of Modularity and Reusability Quality in Refactoring Object-Oriented Program Code

Code smells are a common problem in object-oriented programming that can reduce the quality of software maintainability. To minimize this impact, refactoring techniques are needed that can improve code quality from the early stages of development. However, empirical evidence regarding the effectiveness of refactoring on software quality is still limited. Therefore, this study proposes an evaluation of the impact of refactoring on two sub-characteristics of maintainability, namely modularity and reusability, using metrics based on the ISO/IEC 25023 standard. Refactoring is carried out based on code smell identification using SonarQube and tested on three Java software projects. The study shows that refactoring Long Method and Long Parameter List significantly improves modularity and reusability in object-oriented software. MMo-1-G increasing by up to 0.014 for Long Method and 0.021 for Long Parameter List, MMo-2-S increasing by up to 0.024 for Long Method, and MRe-1-G increasing by up to 0.014. MRe-2-S remained unchanged due to the absence of documented coding rules. These results indicate that refactoring generally provides improvements in the quality of modularity and reusability, although the impact is relatively small and varies from project to project. These findings confirm that refactoring can contribute to improving the maintainability of object-oriented software.