A Classification of Refactoring Methods Based on Software Quality Attributes

Refactoring is the process of improving the design of existing code by changing its internal structure without affecting its external behavior. Refactoring tends to improve software quality by improving design, improving readability and reducing 'bugs'. There are many different refactoring methods, each having a particular purpose and effect. Consequently, the effect of refactoring methods on software quality attributes may vary. Moreover, it is often unclear to software designers how to use refactoring methods to improve specific quality attributes. In this paper, we propose a classification of refactoring methods based on their measurable effect on software quality attributes. This, in turn, helps software designers choose appropriate refactoring methods that will improve the quality of their designs, based on the design objectives. It also enables them to predict the quality drift caused by using particular refactoring methods.