The Impact of Refactoring LegacySystems on Code Quality Metrics

Sammanfattning: Maintaining legacy code can be difficult, it can also be hard to know whether what you are doing tomaintain the code is actually beneficial or not. This paper examines the impact of refactoring on codequality by systematically applying proven refactoring techniques and measuring its effect on codequality through code metrics.As an application at Xylem was being modified the application was simultaneously refactored. Beforeany refactoring was done the code quality was measured by maintainability index, cyclomaticcomplexity, depth of inheritance, class coupling and lines of code. Some parts of the application werere-written, others were refactored. By measuring the same metrics after the application wasrefactored it was found that the metrics had improved, indicating that the code quality hadincreased.