Table of Contents for
Your Code as a Crime Scene

Version ebook / Retour

Cover image for bash Cookbook, 2nd Edition Your Code as a Crime Scene by Adam Tornhill Published by Pragmatic Bookshelf, 2015
  1. Title Page
  2. Your Code as a Crime Scene
  3. Your Code as a Crime Scene
  4. For the Best Reading Experience...
  5. Table of Contents
  6. Early praise for Your Code as a Crime Scene
  7. Foreword by Michael Feathers
  8. Acknowledgments
  9. Chapter 1: Welcome!
  10. About This Book
  11. Optimize for Understanding
  12. How to Read This Book
  13. Toward a New Approach
  14. Get Your Investigative Tools
  15. Part 1: Evolving Software
  16. Chapter 2: Code as a Crime Scene
  17. Meet the Problems of Scale
  18. Get a Crash Course in Offender Profiling
  19. Profiling the Ripper
  20. Apply Geographical Offender Profiling to Code
  21. Learn from the Spatial Movement of Programmers
  22. Find Your Own Hotspots
  23. Chapter 3: Creating an Offender Profile
  24. Mining Evolutionary Data
  25. Automated Mining with Code Maat
  26. Add the Complexity Dimension
  27. Merge Complexity and Effort
  28. Limitations of the Hotspot Criteria
  29. Use Hotspots as a Guide
  30. Dig Deeper
  31. Chapter 4: Analyze Hotspots in Large-Scale Systems
  32. Analyze a Large Codebase
  33. Visualize Hotspots
  34. Explore the Visualization
  35. Study the Distribution of Hotspots
  36. Differentiate Between True Problems and False Positives
  37. Chapter 5: Judge Hotspots with the Power of Names
  38. Know the Cognitive Advantages of Good Names
  39. Investigate a Hotspot by Its Name
  40. Understand the Limitations of Heuristics
  41. Chapter 6: Calculate Complexity Trends from Your Code’s Shape
  42. Complexity by the Visual Shape of Programs
  43. Learn About the Negative Space in Code
  44. Analyze Complexity Trends in Hotspots
  45. Evaluate the Growth Patterns
  46. From Individual Hotspots to Architectures
  47. Part 2: Dissect Your Architecture
  48. Chapter 7: Treat Your Code As a Cooperative Witness
  49. Know How Your Brain Deceives You
  50. Learn the Modus Operandi of a Code Change
  51. Use Temporal Coupling to Reduce Bias
  52. Prepare to Analyze Temporal Coupling
  53. Chapter 8: Detect Architectural Decay
  54. Support Your Redesigns with Data
  55. Analyze Temporal Coupling
  56. Catch Architectural Decay
  57. React to Structural Trends
  58. Scale to System Architectures
  59. Chapter 9: Build a Safety Net for Your Architecture
  60. Know What’s in an Architecture
  61. Analyze the Evolution on a System Level
  62. Differentiate Between the Level of Tests
  63. Create a Safety Net for Your Automated Tests
  64. Know the Costs of Automation Gone Wrong
  65. Chapter 10: Use Beauty as a Guiding Principle
  66. Learn Why Attractiveness Matters
  67. Write Beautiful Code
  68. Avoid Surprises in Your Architecture
  69. Analyze Layered Architectures
  70. Find Surprising Change Patterns
  71. Expand Your Analyses
  72. Part 3: Master the Social Aspects of Code
  73. Chapter 11: Norms, Groups, and False Serial Killers
  74. Learn Why the Right People Don’t Speak Up
  75. Understand Pluralistic Ignorance
  76. Witness Groupthink in Action
  77. Discover Your Team’s Modus Operandi
  78. Mine Organizational Metrics from Code
  79. Chapter 12: Discover Organizational Metrics in Your Codebase
  80. Let’s Work in the Communication Business
  81. Find the Social Problems of Scale
  82. Measure Temporal Coupling over Organizational Boundaries
  83. Evaluate Communication Costs
  84. Take It Step by Step
  85. Chapter 13: Build a Knowledge Map of Your System
  86. Know Your Knowledge Distribution
  87. Grow Your Mental Maps
  88. Investigate Knowledge in the Scala Repository
  89. Visualize Knowledge Loss
  90. Get More Details with Code Churn
  91. Chapter 14: Dive Deeper with Code Churn
  92. Cure the Disease, Not the Symptoms
  93. Discover Your Process Loss from Code
  94. Investigate the Disposal Sites of Killers and Code
  95. Predict Defects
  96. Time to Move On
  97. Chapter 15: Toward the Future
  98. Let Your Questions Guide Your Analysis
  99. Take Other Approaches
  100. Let’s Look into the Future
  101. Write to Evolve
  102. Appendix 1: Refactoring Hotspots
  103. Refactor Guided by Names
  104. Bibliography
  105. You May Be Interested In…

Explore the Visualization

The circle-packing visualization used earlier is based on an algorithm from D3.js,[14] a JavaScript library based on data-driven documents. We won’t dig deeper into D3.js, as that is enough material for a book of its own. Instead, we’ll explore a ready-made visualization.

Before we start, I want to remind you that the strategies we are learning in this book don’t depend on specific tools. D3.js is just one of the many ways to visualize the code. Other options include:

  • Spreadsheets: Since we’re using CSV as the output format, any spreadsheet application lets you visualize the results from Code Maat. Spreadsheet applications are great for processing your analysis results (for example, sorting and filtering the resulting data).

  • R programming language:[15] The programming language R is a complete environment for both statistical computations and data visualizations. It has a steeper learning curve, but it pays off if you want to dive deeper into data analysis.

Launch the Hotspot Visualization

If you haven’t done it already, download the samples from the Code Maat distribution[16] accompanying this book. Unpack the samples and open a command prompt in that directory.

The visualization is an html file, so you can open it in any web browser. The html file will load a JSON resource describing our hotspots. Modern browsers introduce a security restriction on that. To make it work flawlessly, launch Python’s SimpleHTTPServer in the sample/hibernate directory:

​ 
prompt>​ python -m SimpleHTTPServer 8888​

Point your browser to http://localhost:8888/hibzoomable.html. You should now see a familiar picture: the image we saw earlier.

Use Interactive Hotspot Visualizations

The resulting patterns do look cool—who said large-scale software isn’t beautiful? But we’re not here to marvel at its beauty. Instead, click on one of the circles. The first thing you notice is that the visualization is interactive, as shown in the following figure.

images/Chp4_hibzoom.png

An interactive visualization lets you chose your own level of detail. If you see a hot area, zoom in to explore it further.

To get this visual advantage, we need to discuss one more trick to decide which modules to include.

Include All Modules in the Visualization

Look at the preceding figure again. See how the hotspots pop out? The reason is that the entire codebase is visualized, not just code we have recorded changes for. We get that for free, since cloc includes size metrics for all modules in the current snapshot. We then apply color only to the modules that changed within the period of interest.

This visualization makes it easy to toggle between analysis findings and the actual code they represent. Another win is that you get a quick overview of both volatile clusters and the stable parts of the system. Let’s see what that distribution of hotspots tells us about our code.