Static Code Analysis
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The document discusses static code analysis tools such as Checkstyle, Findbugs, PMD, and Lint, which help identify issues in Java code without executing it. It includes examples of how to implement these tools in Gradle, highlighting their purposes such as checking for code quality, programming flaws, and structural issues. Additionally, the document provides resources for further reading and understanding of clean coding practices and tools.
Static Code Analysis
- 3. @brwngrldev +AnnyceDavis “I’ll be learning something new on my deathbed.”
- 4. Checking your program for errors without executing it What is it? @brwngrldev
- 6. 1 / 7 - 10 @brwngrldev
- 11. Checkstyle “… a development tool to help programmers write Java code that adheres to a coding standard.”
- 13. apply plugin: ‘checkstyle’ task checkstyle(type: Checkstyle) { description 'Checks if the code passes quality standards' group 'verification' configFile file(‘checkstyle.xml') … }
- 14. <module name=“MethodLength"> <property name="max" value=“60"/> </module> <module name=“LineLength"> <property name="max" value=“120"/> </module> <module name=“CyclomaticComplexity"> <property name="max" value=“8"/> </module> … playerControlConfig.setShowClosedCaptionsButton(a.getBo
- 15. <module name=“CyclomaticComplexity"> <property name="max" value=“8"/> </module>
- 16. Example
- 17. public void overlyComplexMethod(Video video) { if (video != null && video.getStreamUrl() != null) { switch (video.getCategory()) { case "CAT1" : playVideo(video); if (video.getLargeImageUrl() == null) { video.setLargeImageUrl("http://www.largeImage.png"); } updateMetadata(video); break; case "CAT2" : if (video.getLargeImageUrl() == null) { video.setLargeImageUrl("http://www.smallImage.png");
- 18. … warning: Cyclomatic Complexity is 9
- 19. public void overlyComplexMethod(Video video) { if (video != null && video.getStreamUrl() != null) { updateVideoBasedOnCategory(video); } } private void updateVideoBasedOnCategory(Video video) { switch (video.getCategory()) { case "CAT1" : playVideo(video); if (video.getLargeImageUrl() == null) { video.setLargeImageUrl("http://www.largeImage.png"); } updateMetadata(video); break; 7
- 20. switch (video.getCategory()) { case "CAT1" : playVideo(video); updateMetaDataAndUrl(video, "http://www.largeImage.png"); break; … 4 @brwngrldev
- 21. Review… • Formatting • Code Complexity • Refactor Gradually @brwngrldev Checkstyle 1
- 22. FindBugs
- 23. But this… “…inspect Java bytecode for occurrences of bug patterns”
- 24. apply plugin: ‘findbugs’ task findbugs(type: FindBugs) { description 'Run findbugs' group 'verification' effort 'max' excludeFilter file('findbugs-exclude.xml') … }
- 26. Example
- 27. gradle findbugs
- 30. Review… • Bug Patterns • Not Always Right • Use the Filters FindBugs 2 @brwngrldev
- 32. PMD “…finds common programming flaws like unused variables, empty catch blocks…”
- 33. apply plugin: ‘pmd’ task pmd(type: Pmd) { description 'Run pmd' group 'verification' ruleSetFiles = files("./qa-checks/pmd-ruleset.xml") … }
- 34. <ruleset> <rule ref="rulesets/java/braces.xml" /> <rule ref="rulesets/java/strings.xml" /> <rule ref="rulesets/java/basic.xml" /> … </ruleset>
- 35. Braces Ruleset
- 36. Example
- 37. gradle pmd
- 38. Find out why
- 39. Fix it…
- 40. Review… • Possible Bugs • Wasteful Usage • Duplicate Code @brwngrldev PMD 3
- 41. Ewww!!!
- 42. “…checks for structural code problems that could affect the quality and performance of your application.” Lint
- 44. Example
- 45. Android Lint <lint> <issue id="IconColors" severity="ignore" /> <issue id="IconMissingDensityFolder" severity="ignore" /> <issue id="UnusedResources"> <ignore path="**/config.xml" /> </issue> … </lint>
- 49. Review • Structural Issues • Exclude Checks • Continuous Integration Lint 4 @brwngrldev
- 51. Resources • Clean Code - http://amzn.to/1DJybxH • Effective Java - http://amzn.to/1Ku8Xel • Google Code Style - http://goo.gl/8Pf6J3 • QA Checks - http://git.io/vCMwc • Conquering Cyclomatic Complexity - http://goo.gl/lRoPXN • Using Android Lint - http://goo.gl/Zl2BPx • Static Code Analysis Tools - https://goo.gl/0Hczxn @brwngrldev
- 52. Photo Credits • Slide 7 - https://www.flickr.com/photos/orinrobertjohn/13068719 • Slide 20 - https://www.flickr.com/photos/oakleyoriginals/2750185692 • Slide 41 - https://commons.wikimedia.org/wiki/File:Navel_lint_ball.jpg • Slide 50 - https://pixabay.com/en/thumb-success-successful-fan- faust-328420/ @brwngrldev