EvoLens: LensView Visualizations of Evolution Data

1
EvoLensLens-View Visualizations of Evolution
Data

• Jacek Ratzinger
• Michael Fischer
• Harald Gall
• Vienna University of Technology, Austria
• University of Zurich, Switzerland

2
Outline

• Motivation
• Software Evolution
• EvoLens Approach
• Visualization
• Example
• Related Work
• Conclusions and Future Work

3
Motivation

• Software evolves changes its
• size,
• complexity, and
• characteristics
• Major costs not because of bugs,
• but new and changing requirements
• Lean Business

4
Software Evolution Analysis

• Version control to coordinate team development
  activities
• Vast information in version control systems
• Visualize information to support team work
• Assessment of maintainability
• Re-engineering (Refactoring)

5
EvoLens Approach

• Data source
• modification reports (in particular CVS)
• Change coupling based on common change behavior
• Color indicating growth metrics
• Timescale -gt sliding time window

6
Visualization (Abstractions)

• Time
• on the basis of version history data
• Hierarchies
• on the basis of software structure
• Change Couplings
• as representation of common change histories of
  software parts

7
Case Study

• PACS (Picture Archiving and Communication System)
• Java
• 5.500 Classes (500.000 LOC)
• April 1999 June 2005
• Evolution Data
• CVS (Concurrent Versions System)

8
Analysis Phases

• Period 1 January 2002 March 2003
• Software Evolution Analysis
• assessment of period 1
• --gt recommendations for restructuring/refactoring
• --gt refactorings applied
• Period 2 April 2003 June 2004
• Recurring analysis
• assessment of evolution period 2
• evaluation of refactorings after period 1

Analysis
Analysis
Period 2
Period 1
9
Gross Structure Time Frame 6 Months
submodule with most intensive coupling
several internal couplings
10
Unfolded Package Main
strongly coupled elements
11
Visualization of Variable Selection
simple frame title why coupling ?
startup class with reasonable coupling
new functionality added for image display
12
Changing Threshold of Coupling
Design erosion no separation of concerns
-gt Refactoring mediator
13
Sliding Time Window6 Months Earlier
no detectable design erosion
14
Related Work

• Fisheye Views Focus Context
• SHriMP Nested Graph Visualization
• Xia Tool for Evolution Data
• eRose Amazon for Software Development
• Coupling and Cohesion Metrics for Software
  Assessment

15
Conclusions Future Work

• Navigation facilities in-depth analysis
• Visualization support for detection of hot-spots
  and design erosion
• No separation of concerns
• Spaghetti code
• Poorly designed inheritance hierarchies
• Integration of Bugzilla data

16
Thank you for your attention!