ABMMRS Eradicator: Improving Accuracy in Recommending Move Methods for Web-based MVC Projects and Libraries Using Method's External Dependencies

摘要

Move Method Refactoring (MMR) is used to place highly coupled methods in appropriate classes for making source code more cohesive. Like other refactoring techniques, it is mandatory that applying MMR will preserve applications' behaviors. However, traditional MMR techniques failed to meet this essential precondition for Action methods in web-based application and API methods in libraries projects. The reason is that applying MMR on these methods changes the behaviors of the projects by raising Application-breaking issues, for instance, failure of browser requests and compilation errors in client projects. To resolve this problem, developers are suggested to manually check Action and API methods while applying MMR. However, manually inspecting thousands of lines of code for these issues is a time-consuming and hectic task. In this paper, an advanced MMR technique is proposed which automatically identifies Application-breaking MMR suggestions. This technique first takes the initial move method suggestions from the existing prominent MMR techniques e.g. JDeodorant. For each of the suggestions, it parses the source code and construct Abstract Syntax Tree to examine two types of usage. One is whether a suggestion has not been used in any unit test and Regular Class, and another is whether the suggestion has been used in unit test classes only. If any MMR suggestion is found having one of these two types of usage or both, the respective suggestion is marked as Application-breaking. In order to evaluate the proposed technique, several experiments have been conducted on open source projects. The experimental results show that the proposed technique achieved 96.4% Precision, 90% Recall and 93.1% F-score in detecting Application-breaking MMR suggestions, because of considering external dependencies of the MMR suggestions.