An Investigation into the Characteristics of Methods for Extract Method Refactoring

Abstract

“Extract Method” is a refactoring pattern that extracts a part of an existing method as a new method. Although extract method refactoring is an effective way to decompose long and non-cohesive methods in general, how developers choose methods for “Extract Method” refactoring is still unexamined. For supporting this refactoring, the investigation of it is necessary. In this study, we investigated the differences of the size and cohesion of methods between refactored methods and not-refactored methods in open source software. The result shows significant deliverances in the most cases.