A metric-based approach to identifying refactoring opportunities for merging code clones in a Java software system

A code clone is a code fragment that has other code fragments identical or similar to it in the source code. The presence of code clones is generally regarded as one factor that makes software maintenance more difficult. For example, if a code fragment with code clones is modified, it is necessary to consider whether each of the other code clones has to be modified as well. Removing code clones is one way of avoiding problems that arise due to the presence of code clones. This makes the source code more maintainable and more comprehensible. This paper proposes a set of metrics that suggest how code clones can be refactored. As well, the tool Aries, which automatically computes these metrics, is presented. The tool gives metrics that are indicators for certain refactoring methods rather than suggesting the refactoring methods themselves. The tool performs only lightweight source code analysis; hence, it can be applied to a large number of code lines. This paper also describes a case study that illustrates how this tool can be used. Based on the results of this case study, it can be concluded that this method can efficiently merge code clones. Copyright © 2008 John Wiley & Sons, Ltd.

[1]  Brenda S. Baker,et al.  Parameterized Duplication in Strings: Algorithms and an Application to Software Maintenance , 1997, SIAM J. Comput..

[2]  Martin P. Robillard,et al.  Tracking Code Clones in Evolving Software , 2007, 29th International Conference on Software Engineering (ICSE'07).

[3]  Shinji Kusumoto,et al.  Non-commercial Research and Educational Use including without Limitation Use in Instruction at Your Institution, Sending It to Specific Colleagues That You Know, and Providing a Copy to Your Institution's Administrator. All Other Uses, Reproduction and Distribution, including without Limitation Comm , 2022 .

[4]  Michael W. Godfrey,et al.  "Cloning Considered Harmful" Considered Harmful , 2006, 2006 13th Working Conference on Reverse Engineering.

[5]  Tom Mens,et al.  A survey of software refactoring , 2004, IEEE Transactions on Software Engineering.

[6]  Stan Jarzabek,et al.  Unifying clones with a generative programming technique: a case study: Practice Articles , 2006 .

[7]  Magdalena Balazinska,et al.  Advanced clone-analysis to support object-oriented system refactoring , 2000, Proceedings Seventh Working Conference on Reverse Engineering.

[8]  Magdalena Balazinska,et al.  Measuring clone based reengineering opportunities , 1999, Proceedings Sixth International Software Metrics Symposium (Cat. No.PR00403).

[9]  Tudor Gîrba,et al.  How Developers Copy , 2006, 14th IEEE International Conference on Program Comprehension (ICPC'06).

[10]  Mohamed E. Fayad.  Software Maintenance , 2005, IEEE Softw..

[11]  Miryung Kim,et al.  An empirical study of code clone genealogies , 2005, ESEC/FSE-13.

[12]  Shinji Kusumoto,et al.  Simultaneous Modification Support based on Code Clone Analysis , 2007, 14th Asia-Pacific Software Engineering Conference (APSEC'07).

[13]  Martin Fowler,et al.  Refactoring - Improving the Design of Existing Code , 1999, Addison Wesley object technology series.

[14]  Miryung Kim,et al.  An ethnographic study of copy and paste programming practices in OOPL , 2004, Proceedings. 2004 International Symposium on Empirical Software Engineering, 2004. ISESE '04..

[15]  Shinji Kusumoto,et al.  CCFinder: A Multilinguistic Token-Based Code Clone Detection System for Large Scale Source Code , 2002, IEEE Trans. Software Eng..

[16]  Zoltán Ádám Mann,et al.  Three public enemies: cut, copy, and paste , 2006, Computer.

[17]  Stanislaw Jarzabek,et al.  Effective Software Maintenance , 2006 .

[18]  Susan Horwitz,et al.  Using Slicing to Identify Duplication in Source Code , 2001, SAS.

[19]  Serge Demeyer,et al.  Evaluating clone detection techniques from a refactoring perspective , 2004 .

[20]  Lowell Jay Arthur.  Software evolution: the software maintenance challenge , 1988 .

[21]  Stan Jarzabek,et al.  Unifying clones with a generative programming technique: a case study , 2006, J. Softw. Maintenance Res. Pract..

[22]  Andrew Begel,et al.  Managing Duplicated Code with Linked Editing , 2004, 2004 IEEE Symposium on Visual Languages - Human Centric Computing.

[23]  Yuanyuan Zhou,et al.  CP-Miner: finding copy-paste and related bugs in large-scale software code , 2006, IEEE Transactions on Software Engineering.

[24]  Stan Jarzabek,et al.  Eliminating redundancies with a "composition with adaptation" meta-programming technique , 2003, ESEC/FSE-11.

[25]  Tom Lam,et al.  A software maintenance survey , 1994, Proceedings of 1st Asia-Pacific Software Engineering Conference.

[26]  Ettore Merlo,et al.  Experiment on the automatic detection of function clones in a software system using metrics , 1996, 1996 Proceedings of International Conference on Software Maintenance.