Centralizing PMD rules for use with Maven.

PMD has long been a great report to find out many useful details of your code base.

I find that the default ruleset does not contain some checks that I find very useful especially when I have more junior developers. I can catch many problematic errors.

<?xml version=”1.0″?>

<ruleset name="Custom ruleset"
 xmlns="http://pmd.sf.net/ruleset/1.0.0"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://pmd.sf.net/ruleset/1.0.0 http://pmd.sf.net/ruleset_xml_schema.xsd"
 xsi:noNamespaceSchemaLocation="http://pmd.sf.net/ruleset_xml_schema.xsd">

 <description>
 This ruleset checks my code for bad stuff
 </description>

 <!-- Here's some rules we'll specify one at a time -->
 <rule ref="rulesets/basic.xml"/>

 <!-- We want to customize this rule a bit, change the message and raise the priority  -->
 <rule ref="rulesets/basic.xml/EmptyCatchBlock"
 message="Must handle exceptions">
 <priority>2</priority>
 </rule>

 <rule ref="rulesets/codesize.xml"/>
 <rule ref="rulesets/codesize.xml/CyclomaticComplexity">
     <properties>
         <property name="reportLevel" value="5"/>
     </properties>
 </rule>
 <rule ref="rulesets/controversial.xml" />
 <rule ref="rulesets/coupling.xml" />

 <rule ref="rulesets/design.xml" />
 <rule ref="rulesets/imports.xml" />
 <rule ref="rulesets/logging-java.xml" />

 <rule ref="rulesets/optimizations.xml" />
 <rule ref="rulesets/strictexception.xml" />
 <rule ref="rulesets/strings.xml" />
 <rule ref="rulesets/sunsecure.xml" />
 <rule ref="rulesets/typeresolution.xml" />
 <rule ref="rulesets/unusedcode.xml" />

 <rule ref="rulesets/unusedcode.xml/UnusedLocalVariable" />
 <rule ref="rulesets/unusedcode.xml/UnusedPrivateField" />

 <!-- Note we want everything from braces.xml except WhileLoopsMustUseBraces -->
 <rule ref="rulesets/braces.xml">
     <exclude name="WhileLoopsMustUseBraces"/>
 </rule>
</ruleset>

I uploaded my configuration to my server (http://www.baselogic.com/pmd-rules.xml), then I can access this on any project I am working on:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-pmd-plugin</artifactId>
    <configuration>
    <rulesets>
        <ruleset>http://www.baselogic.com/pmd-rules.xml</ruleset>
    </rulesets>
    <linkXref>true</linkXref>
    <targetJdk>${compiler.version}</targetJdk>
    </configuration>
</plugin>

If you find you like your PMD a bit different, just customize the rules and put onto your webserver, then you can carry your rules with you.