Do's and don'ts regarding Code Quality Assurance. Presentation given to a technical Java audience.

1. CODE QUALITY ASSURANCE
Jan 15, 2013
Bart Blommaerts
bart.blommaerts@hp.com
EMEA NG Java & WEB: HP Belgium
©2010 Hewlett-Packard Development Company, L.P.
The information contained herein is subject to change without
notice

2. Agenda
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Why do we need clean code?
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What is clean code?
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How do we write clean code?
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How do we test clean code?
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How do we measure clean code?
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Disclaimer: clean code vs. great code
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Q&A
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3. Why do we need clean code?
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4. Why do we need clean code?
Objectives
– Easy
to read and understand
– Unnecessary
– Maintaining
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and extending code is easier
First step towards re-use!
– Project
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code and noise are removed
lifecycle cost will be reduced
Cost of owning a mess ..
“Writing clean code is what you must do in order to call yourself a
professional. There is no reasonable excuse for doing anything less
than your best.”
Robert C. Martin
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5. What is clean code?
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Simple and direct
Human readable
Efficient
No duplications: DRY
Made for the problem
Easy to enhance
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6. How do we write clean code?
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SRP: Single responsibility principle
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Stepdown Rule
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Do One Thing
Restrict number of arguments (3 is a lot ..)
Boy Scout Rule
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Leave code better than you found it
Don’t comment bad code, rewrite it
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7. How do we write clean code?
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Meaningful, self-explaining names
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Purpose of a variable, class, method, ..
Avoid disinformation (eg. lblUserName)
Error Handling
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Don’t return null
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Use exceptions rather then return codes
Don’t pass null
Expresses intent
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8. How do we test clean code?
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SRP: Single responsibility principle
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Boy Scout Rule
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Unit test enabler
Add unit tests before refactoring
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Jan 2013

9. How do we test clean code?
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Meaningful names
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Understand what to test
Error Handling
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@Test(expected=CleanCodeException.class)
Fix a bug only once. Write Unit tests when fixing bugs!
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10. How do we measure clean code?
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Sonar integration
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http://sonar.elabs.eds.com:9000/
Maven:
<properties>
<sonar.jdbc.url>
jdbc:mysql://sonar.elabs.eds.com:3306/sonar?useUnicode=true&amp;characterEncoding=utf8
</sonar.jdbc.url>
<sonar.jdbc.driver>com.mysql.jdbc.Driver</sonar.jdbc.driver>
<sonar.jdbc.username>x</sonar.jdbc.username>
<sonar.jdbc.password>x</sonar.jdbc.password>
<sonar.host.url>http://sonar.elabs.eds.com:9000</sonar.host.url>
</properties>
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11. How do we measure clean code?
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Ant:
<!-- Sonar properties -->
<property name="sonar.jdbc.url"
value="jdbc:mysql://sonar.elabs.eds.com:3306/sonar?useUnicode=true&amp;characterEncoding=utf8" />
<property name="sonar.jdbc.driverClassName" value="com.mysql.jdbc.Driver" />
<property name="sonar.jdbc.username" value="x" />
<property name="sonar.jdbc.password" value="x" />
<property name="sonar.host.url" value="http://sonar.elabs.eds.com:9000" />
<!-- Sonar target -->
<target name="sonar" depends="compile">
<sonar:sonar workDir="." key="be.vlaanderen.vip:xfire" version="02.00"
xmlns:sonar="antlib:org.sonar.ant">
<sources>
<path location="${project.dir.src}" />
</sources>
</sonar:sonar>
</target>
<!-- Sonar task -->
<taskdef uri="antlib:org.sonar.ant" resource="org/sonar/ant/antlib.xml">
<classpath>
<fileset dir="${project.dir.lib}">
<include name="sonar-ant-task-1.0.jar" />
</fileset>
</classpath>
</taskdef>
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12. How do we measure clean code?
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Demo!
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13. Disclaimer: clean code vs. great code
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Primary goal: making it work
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SRP
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But: no methods with 1 line of code
But: don’t write a huge amount of tiny classes
Boy Scout Rule
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Don’t go overboard
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14. Q& A
http://www.osnews.com/comics
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15. THANKS FOR YOUR ATTENTION
©2010 Hewlett-Packard Development Company, L.P.
The information contained herein is subject to change without
notice