ERA - Measuring Disruption from Software Evolution Activities Using Graph-Based Metrics


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Paper: Measuring Disruption from Software Evolution Activities Using Graph-Based Metrics

Authors: Prashant Paymal, Rajvardhan Patil, Sanjukta Bhowmick and Harvey Siy

Session: Early Research Achievements Track Session 3: Managing and Supporting Software Maintenance Activities

Published in: Education, Technology
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ERA - Measuring Disruption from Software Evolution Activities Using Graph-Based Metrics

  1. 1. Measuring Disruption from Software Evolution Activities Using Graph- Based MetricsPrashant Paymal, Rajvardhan Patil, Sanjukta Bhowmick, Harvey Siy Department of Computer Science, University of Nebraska at Omaha
  2. 2. Introduction• Real world software systems have large numbers of components (e.g. classes, functions, etc.)• It is difficult to get a quick summary of how system evolved after a major change such as perfective maintenance activity or new software release
  3. 3. Case StudyVersion Date Commit Messages V1 3/9/2001 Merge to JHotDraw 5.2 (using JFC/Swing GUI components) V2 10/24/2001 Before merge for version 5.3 (dnd, undo…) merge dnd (before 5.3) V3 8/4/2002 After various merges… (before 5.4 relaease) V4 11/8/2002 Refactor to use StandardStorageFormat as a superclass V5 5/8/2003 Refactoring of Cursor. – java.awt.Cursor(class) has been systematically replaced V6 1/9/2004 After renaming the CH.ifa.draw to org.jhotdraw• Our case study consists of six versions of JHotDraw from March 2001 to January 2004
  4. 4. Network Construction• Extracted relationships from these versions (inheritance, implementation, method calls and class member access, object declaration and instantiation)• Network was created by connecting class dependencies, where each edge (u, v) is a dependency from class „u‟ to class „v‟
  5. 5. Vertex Properties• Degree Distribution ▫ Frequency of vertices per degree, scale free for most real world networks• Clustering Coefficient ▫ Connections between neighbors• Betweenness Centrality ▫ Ratio of shortest paths through a vertex• Articulation Points ▫ It‟s removal would cause the network to become disconnected
  6. 6. • Network representing Version 1, ▫ Lighter Nodes: High Betweenness Centrality ▫ Larger Nodes: High Clustering Coefficient
  7. 7. Objective• Extract key combinatorial properties from these six networks that would enable us to detect evolutionary characteristics such as ▫ Points of significant change in the software ▫ How these changes affect crucial classes in the network
  8. 8. Change in Vertex Properties• All properties increased with version number
  9. 9. Correlation Between Properties ▫ Positive correlation between degree and betweenness centrality ▫ Correlation between clustering coefficient and betweenness centrality changes across versions
  10. 10. Disruption in Values and Rank• We examine how the relationships between these properties changed from one version to the next
  11. 11. Disruption in Values and Rank
  12. 12. Disruption in Values and Rank
  13. 13. Identifying Crucial Vertices• High ▫ If vertex has high rank (within top 25) in at least one of the following categories• Extra High ▫ If vertex has high rank in at least two categories• Low ▫ If vertex has zero value for any one vertex based properties and is not marked as a High vertex• Extra Low ▫ If it has zero value for both betweenness centrality and clustering coefficient• (High Betweenness Centrality, High Indegree, High Outdegree, High Clustering Coefficient / Articulation Point)
  14. 14. Percentage Breakdown of All Verticesin Each Version
  15. 15. Percentage Breakdown of Vertices(Common to All Versions) Other Extra Low Low Extra High High
  16. 16. Analysis of Newly Added Vertices
  17. 17. Bug Frequencies• Changes that have the keywords “bug fix” in the change log• The periods with high percentage are also the periods after the high disruption
  18. 18. Conclusion• The significant evolutionary changes occur between Version 2 – Version 3 and Version 4 – Version 5• The network has grown cumulatively. Newer vertices tend to get added to the peripheries of the network• The top 25 ranking of vertices was generally stable across versions. Important nodes stay important. This indicates stability in the design.• The bug frequency is higher after Version 3 and Version 5. The degree of disruption can help explain why bug incidence increases (future work)
  19. 19. Acknowledgement• Nebraska EPSCoR• College of IS&T, University of Nebraska at Omaha
  20. 20. Thank you!