pmd-ruleset.xml

<?xml version="1.0"?>

<ruleset name="PMD HappyCoders ruleset - Hexagonal Architecture"
         xmlns="http://pmd.sourceforge.net/ruleset/2.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://pmd.sourceforge.net/ruleset/2.0.0 https://pmd.sourceforge.io/ruleset_2_0_0.xsd">

    <description>PMD ruleset for HappyCoders.eu (relaxed for Hexagonal Architecture tutorial)</description>

    <!-- Rule reference: https://pmd.github.io/pmd/pmd_rules_java.html -->

    <rule ref="category/java/bestpractices.xml">
        <exclude name="PreserveStackTrace"/>              <!-- We're using very specific exceptions like "ProductNotFoundException"; for those, the stack trace is not important. -->
    </rule>

    <rule ref="category/java/codestyle.xml">
        <exclude name="AtLeastOneConstructor"/>           <!-- I don't think we should implement artificial default constructors. -->
        <exclude name="CommentDefaultAccessModifier"/>    <!-- We don't comment why we make fields private, protected or public. So why should we comment on default access? -->
        <exclude name="LocalVariableCouldBeFinal"/>       <!-- Using 'final' on local variables (in contrast to fields) has no effect on the compiler; IMO it's noise. -->
        <exclude name="MethodArgumentCouldBeFinal"/>      <!-- Using 'final' on method arguments (in contrast to fields) has no effect on the compiler; IMO it's noise. -->
        <exclude name="OnlyOneReturn"/>                   <!-- Outdated in times of short methods. -->
    </rule>

    <rule ref="category/java/codestyle.xml/LongVariable">
        <properties>
            <property name="minimum" value="65" />        <!-- Default max is 16, which is not always enough for a descriptive name; allow longer variables. -->
        </properties>
    </rule>

    <rule ref="category/java/codestyle.xml/ShortClassName">
        <properties>
            <property name="minimum" value="4" />         <!-- Default minimum is 5, that wouldn't allow a class name like "Cart". -->
        </properties>
    </rule>

    <rule ref="category/java/codestyle.xml/ShortMethodName">
        <properties>
            <property name="minimum" value="2" />         <!-- Default minimum is 3, that wouldn't allow a method name like "id()". -->
        </properties>
    </rule>

    <rule ref="category/java/codestyle.xml/ShortVariable">
        <properties>
            <property name="minimum" value="2" />         <!-- Default minimum is 3, that wouldn't allow a variable name like "id". -->
        </properties>
    </rule>

    <rule ref="category/java/design.xml">
        <exclude name="LawOfDemeter"/>                    <!-- This rule also prohibits a fluent programming style. -->
        <exclude name="LoosePackageCoupling"/>            <!-- This rule requires configuration. -->
    </rule>

    <rule ref="category/java/documentation.xml">
        <exclude name="CommentRequired"/>                 <!-- Would require comments on all fields, public methods, and constructors. Good names are a much better documentation. -->
        <exclude name="CommentSize"/>                     <!-- Don't limit the size of comments. -->
    </rule>

    <rule ref="category/java/errorprone.xml">
        <exclude name="AvoidFieldNameMatchingMethodName"/><!-- I personally like using the field name also as an accessor name for final fields (like in records). -->
        <exclude name="MissingSerialVersionUID"/>         <!-- We're not using serialization. -->
    </rule>

    <rule ref="category/java/errorprone.xml/AvoidLiteralsInIfCondition">
        <properties>
            <property name="ignoreMagicNumbers" value="-1,0,1,2" /><!-- Allow a few other literals than the default (-1, 0). -->
        </properties>
    </rule>

    <rule ref="category/java/multithreading.xml">
        <exclude name="UseConcurrentHashMap"/>            <!-- I prefer to decide on my own. -->
    </rule>

    <rule ref="category/java/performance.xml"/>
    <rule ref="category/java/security.xml"/>

</ruleset>