Refactoring Support Based on Code Clone Analysis

Software maintenance is the most expensive activity in software development. Many software companies spent a large amount of cost to maintain the existing software systems. In perfective maintenance, refactoring has often been applied to the software to improve the understandability and complexity. One of the targets of refactoring is code clone. A code clone is a code fragment in a source code that is identical or similar to another. In an actual software development process, code clones are introduced because of various reasons such as reusing code by ‘copy-and-paste’ and so on. Code clones are one of the factors that make software maintenance difficult. In this paper, we propose a method which removes code clones from object oriented software by using existing refactoring patterns, especially “Extract Method” and “Pull Up Method”. Then, we have implemented a refactoring supporting tool based on the proposed method. Finally, we have applied the tool to an open source program and actually perform refactoring.