Analyzing Software Repositories The practical side

1
Analyzing Software RepositoriesThe practical side

• Robert-Jan Bijl

2
Contents

• Recap
• Practical Applications
• Findings
• Conclusion

3
Contents

• Recap
• Practical Applications
• Conclusion

4
Recap

• In any (big) software project, you need
  versioning
• Parallel editing of files
• Keeping track of changes
• Being able to revert to older versions
• Also used to analyze properties of the software
• And even to predict bugs

5
The Tools

• Analyzing Developer Effort (Fractal Figures)
• Change Coupling Analysis (Evolution Radar)
• Trend Analysis and Hotspot Detection (ArchView)

6
Analyzing Developer Effort

• Interesting to see what developer created what
  part of the software Fractal Figure
  visualization
• We can also have a quantitative measure

7
Evolution Radar
8
ArchView

• Obtain metric values of modules
• Assign them to feature vectors
• Normalize and display in a Kiviat diagram

9
Contents

• Recap
• Practical Applications
• Conclusion

10
Practical Applications

• In theory
• Fractal Figures
• Evolution Radar
• ArchView
• In practice
• ckjm
• Excel
• DA4Java

11
The failures

• Both FractalFigures and ArchView so called proof
  of concepts, not maintained software
• EvolutionRadar refused to work properly on my
  machine

12
Plan B

• ckjm applies the metrics described by Chidamber
  and Kemerer
• Use Excel to visualize these metrics
• Though unfortunately not in Kiviat diagrams
• Use DA4Java to compare two revisions of the
  dataset to try and explain the differences in
  metrics

13
The dataset

• ArgoUML
• Versions 0.24 and 0.26
• Two modules
• org.argouml.model
• org.aroguml.ui

14
ckjm

• The metrics ckjm will calculate and display for
  each class are the following.
• WMC - Weighted methods per class
• DIT - Depth of Inheritance Tree
• NOC - Number of Children
• CBO - Coupling between object classes
• RFC - Response for a Class
• LCOM - Lack of cohesion in methods
• Ca - Afferent couplings
• NPM - Number of Public Methods

15
org.argouml.model

• Averages
• Only LCOM seemsinteresting

16
Evolizer and DA4Java

• Evolizer is a platform to enable software
  evolution analysis within Eclipse
• DA4Java is an Eclipse plugin to visualize and
  analyze Java source code.
• Source code is visualized with nested graphs.
• Visualization based on a FAMIX model
• FAMIX is a language independent meta-model. The
  current working version is Famix 2.2 and it
  describes the static structure of object-oriented
  software systems.

17
DA4Java
18
(No Transcript)
19
Demonstration
20
Findings

• Started with a file that lost some methods
• Ended up with a removed sub-module
• Neither the dependency graphs, nor the SVN logs
  gave a clear view of what happened

21
Conclusion

• A lot of tools in the literature are just proof
  of concepts
• Getting useful information from metrics is a
  tedious task
• Often stumble into interesting things while
  looking somewhere else initially