Visualization of Clone Detection Results

1. Visualization of Clone Detection Results Eclipse Technology Exchange Workshop OOPSLA 2006 Portland, Oregon Robert Tairas with Jeff Gray and Ira Baxter

2. Code Clones • A sequence of statements that are duplicated in multiple locations in a program Source Code ClonedCode _____ _______ _________ ___ ______ ___ ______ ______ _____ ________ ___ _______________ ____ _______ ______ _________ _____ _______ ________ ___ _______________ _______ _____ _________ _______ ___ ______ ________ __________ _______ ____ _______ ________ ___ _______________ ____ ______ _________ _____ ____ ________ ____ __________ _______ ___ ________ ___ _______________ _____ ________ ___ _______________ ______ _______ ______ _______ _________ _______ ___ ________ ___ _____________ ________ ___ _______________

3. Clones in Source Code • Copy-and-paste parts of code from one location to another • The copied code alreadyworks correctly • No time to be efficient • Research shows that5-10% of large scalecomputer programsare clones (Baxter, 98) Source Code _____ _______ _________ ___ ______ ___ ______ ______ _____ ________ ___ _______________ ____ _______ ______ _________ _____ _______ ________ ___ _______________ _______ _____ _________ _______ ___ ______ ________ __________ _______ ____ _______ ________ ___ _______________ ____ ______ _________ _____ ____ ________ ____ __________ _______ ___ ________ ___ _______________ _____ ________ ___ _______________ ______ _______ ______ _______ _________ _______ ___ ________ ___ _____________

4. Supporting Tool: CloneDR • Commercial clone detection tool developed by Semantic Designs • Finds clones by examining the abstract syntax tree representation of a program • Java version freely available at:http://www.semanticdesigns.com/Products/Clone/register-download.html

5. Supporting tool: AJDT Visualiser Plugin • Part of the AspectJ Development Tools (AJDT) project • AJDT Visualiser website: http://www.eclipse.org/ajdt/visualiser • An extension point to pass information: Bars: Implement IContentProvider Interface Stripes: Implement IMarkupProvider Interface Visualiser View

6. === Tree Clone Tuple ==== Tuple with 7 clones, 3 parameters; similarity = 0.9873417721518988 #4 #10f577d0 #97986c0 Clone 1: 6 lines from Line 43 to 48 File: c:/temp/runtime-EclipseApplication/JHotDraw/src/org/jhotdraw/contrib/WindowMenu.java new AbstractCommand("Cascade", newEditor) { public void execute() { WindowMenu.this.desktop.cascadeFrames(); } public boolean isExecutable() { return super.isExecutable() && (WindowMenu.this.desktop.getAllFrames().length > 0); } } -------------------------------------------------------------------------------- #4 #10f577d0 #979d860 Clone 2: 6 lines from Line 51 to 56 File: c:/temp/runtime-EclipseApplication/JHotDraw/src/org/jhotdraw/contrib/WindowMenu.java new AbstractCommand("Tile", newEditor) { public void execute() { WindowMenu.this.desktop.tileFramesHorizontally(); } public boolean isExecutable() { return super.isExecutable() && (WindowMenu.this.desktop.getAllFrames().length > 0); } } -------------------------------------------------------------------------------- #4 #10f577d0 #9e77f40 Clone 3: 7 lines from Line 52 to 58 File: c:/temp/runtime-EclipseApplication/JHotDraw/src/org/jhotdraw/contrib/CTXWindowMenu.java new AbstractCommand("Cascade", newEditor) { public void execute() { CTXWindowMenu.this.desktop.cascadeFrames(); } public boolean isExecutable() { return super.isExecutable() && (CTXWindowMenu.this.desktop.getAllFrames().length > 0); } } … Clone Detection Results

7. Process Clone Detection Results Plugin CloneDR Detection Info View Config Wizard • Initially, user is assisted by detection process configuration wizard. • CloneDR executes and generates a text file containing its results. These results are parsed by the plugin. • Detection statistics sent to information view and detected clones sent to both textual and graphical view (step 3). 1 3 2 Detected Clones View Results Text File Parser 3 3 Eclipse Platform Detected Clones View AJDT Visualiser Plugin

8. Configuration Wizard • The detection of clones can run on all files or just on pre-selected files • The detection settings for CloneDR are also set in the wizard • Wizard generates a configuration file that will be used by CloneDR

9. Detection Information • Statistical information about the clone detection procedure itself in addition to the configuration settings are displayed in the clone detection results information view.

10. List of Clones • Clone information: • grouped by similarity • source file • starting line number • ending line number • Not new, Simian and SimScan plugins also provide similar reporting

11. Visualiser View • Bars: Source files • Stripes (Kinds): Clones • Mouse over: • Length of clone • Other clones in the same clone group

12. Visualiser View • Additional Options: • Display all bars containing the same clones as in the selected bar • Display all bars containing the selected clone • Open the file containing the selected clone • Open all files containing clones in the same clone group as the selected clone

13. The Big Picture

14. Case Study • Performed on open source applications • JavaGenes, scientific evolutionary software • JHotDraw, a GUI framework • Understanding the results • Clone group in the same class (JavaGenes)

15. Case Study • Understanding the results (continued) • Ubitiquous clones (JHotDraw), methods that: • return a new Rectangle object • draw two ovals (including setting their colors) • setting the undo and redo flags for the drawing view

16. Future Work • A more structured view of the source code files • For OO languages, classes could be displayed in UML-like form. • Demarcation of methods in bars representing source files • Displaying the borders of methods in the view can assist in determining which clones are method-level clones. • Tighter integration of CloneDR in Eclipse • Simplify and speed up the detection and visualization process. Eclipse CloneDR

17. Thank you. Questions? • Visualization of Clone Detection Results: http://www.cis.uab.edu/tairasr/visual • Clone Detection Literature: http://www.cis.uab.edu/tairasr/clones/literature • SoftCom Laboratory: http://www.cis.uab.edu/softcom