rules.xml

<?xml version="1.0"?>
<ruleset name="Custom MyCoRe rules" 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>
    This ruleset contains custom MyCoRe rules
  </description>

  <rule name="MCR.Configuration.PublicFieldsAndMethods"
        language="java"
        message="A field or method annotated with a configuration annotation (like @MCRProperty) needs to be public"
        class="net.sourceforge.pmd.lang.rule.xpath.XPathRule">
    <priority>4</priority>
    <properties>
      <property name="xpath">
        <value>
          //ClassBody/(FieldDeclaration|MethodDeclaration)
            [
                ModifierList/Annotation/ClassType[pmd-java:typeIs('org.mycore.common.config.annotation.MCRFactory')]
              or
                ModifierList/Annotation/ClassType[pmd-java:typeIs('org.mycore.common.config.annotation.MCRInstance')]
              or
                ModifierList/Annotation/ClassType[pmd-java:typeIs('org.mycore.common.config.annotation.MCRInstanceList')]
              or
                ModifierList/Annotation/ClassType[pmd-java:typeIs('org.mycore.common.config.annotation.MCRInstanceMap')]
              or
                ModifierList/Annotation/ClassType[pmd-java:typeIs('org.mycore.common.config.annotation.MCRPostConstruction')]
              or
                ModifierList/Annotation/ClassType[pmd-java:typeIs('org.mycore.common.config.annotation.MCRProperty')]
              or
                ModifierList/Annotation/ClassType[pmd-java:typeIs('org.mycore.common.config.annotation.MCRRawProperties')]
            ]
            [
              not(@Visibility='public')
            ]
        </value>
      </property>
    </properties>
  </rule>
  
  
  <rule name="MCR.Logger.MaxOneField"
        language="java"
        message="There should only be one field with name 'logger' or 'LOGGER' and type 'Logger'"
        class="net.sourceforge.pmd.lang.rule.xpath.XPathRule">
    <priority>4</priority>
    <properties>
      <property name="xpath">
        <value>
          //ClassBody/FieldDeclaration
            [
              VariableDeclarator/VariableId/@Name=('logger','LOGGER')
                or
              ClassType[@SimpleName='Logger']
            ]
            [
              position()>1
            ]
        </value>
      </property>
    </properties>
  </rule>

  <rule name="MCR.Logger.MatchingLoggerType"
        language="java"
        message="A field with name 'logger' or 'LOGGER' should have type 'Logger'"
        class="net.sourceforge.pmd.lang.rule.xpath.XPathRule">
    <priority>4</priority>
    <properties>
      <property name="xpath">
        <value>
          //ClassBody/FieldDeclaration
            [
              VariableDeclarator/VariableId/@Name=('logger','LOGGER')
                and
              not(ClassType[@SimpleName='Logger'])
            ]
        </value>
      </property>
    </properties>
  </rule>

  <rule name="MCR.Logger.MatchingFieldName"
        language="java"
        message="A field with type 'Logger' should have name 'logger' or 'LOGGER'"
        class="net.sourceforge.pmd.lang.rule.xpath.XPathRule">
    <priority>4</priority>
    <properties>
      <property name="xpath">
        <value>
          //ClassBody/FieldDeclaration
            [
              ClassType[@SimpleName='Logger']
                and
              not(VariableDeclarator/VariableId/@Name=('logger','LOGGER'))
            ]
        </value>
      </property>
    </properties>
  </rule>

  <rule name="MCR.Logger.CorrectLoggerType"
        language="java"
        message="A field with type 'Logger' should have name actual type 'org.apache.logging.log4j.Logger'"
        class="net.sourceforge.pmd.lang.rule.xpath.XPathRule">
    <priority>4</priority>
    <properties>
      <property name="xpath">
        <value>
          //ClassBody/FieldDeclaration
            [
              ClassType[@SimpleName='Logger']
                and
              not(ClassType[pmd-java:typeIs('org.apache.logging.log4j.Logger')])
            ]
        </value>
      </property>
    </properties>
  </rule>

  <rule name="MCR.Logger.CorrectStaticInitialisation"
        language="java"
        message="A field with type 'Logger' and name 'LOGGER' should be initialized as 'private static final Logger LOGGER = LogManager.getLogger();'"
        class="net.sourceforge.pmd.lang.rule.xpath.XPathRule">
    <priority>4</priority>
    <properties>
      <property name="xpath">
        <value>
          //ClassBody/FieldDeclaration
            [
              ClassType[@SimpleName='Logger']
                and
              VariableDeclarator/VariableId/@Name='LOGGER'
            ]
            [
              not(
                deep-equal(pmd-java:modifiers(), ('private','static','final'))
                  and
                VariableDeclarator/MethodCall[
                  TypeExpression/ClassType[@SimpleName='LogManager']
                    and
                  @MethodName='getLogger'
                    and
                  count(*)=2
                   and
                  count(ArgumentList/*)=0
                ]
              )
            ]
        </value>
      </property>
    </properties>
  </rule>

  <rule name="MCR.Logger.CorrectDynamicInitialisation"
        language="java"
        message="A field with type 'Logger' and name 'logger' should be initialized as 'protected final Logger logger = LogManager.getLogger(getClass());'"
        class="net.sourceforge.pmd.lang.rule.xpath.XPathRule">
    <priority>4</priority>
    <properties>
      <property name="xpath">
        <value>
          //ClassBody/FieldDeclaration
            [
              ClassType[@SimpleName='Logger']
                and
              VariableDeclarator/VariableId/@Name='logger'
            ]
            [
              not(
                deep-equal(pmd-java:modifiers(), ('protected','final'))
                  and
                VariableDeclarator/MethodCall[
                  TypeExpression/ClassType[@SimpleName='LogManager']
                    and
                  @MethodName='getLogger'
                    and
                  count(*)=2
                    and
                  count(ArgumentList/*)=1
                    and
                  ArgumentList[1][
                    MethodCall[
                      @MethodName='getClass'
                        and
                      count(*)=1
                        and
                      count(ArgumentList/*)=0
                    ]
                  ]
                ]
              )
            ]
        </value>
      </property>
    </properties>
  </rule>

  <rule name="MCR.Logger.IndirectAccess"
        language="java"
        message="A field with name 'Logger' should be accessed directly (either logger.info(...) or this.logger.info(...))"
        class="net.sourceforge.pmd.lang.rule.xpath.XPathRule">
    <priority>4</priority>
    <properties>
      <property name="xpath">
        <value>
          //FieldAccess[@Name='logger'][VariableAccess|ConstructorCall]
        </value>
      </property>
    </properties>
  </rule>

  <!--rule name="MCR.Logger.AbstractClassesShouldHaveDynamic"
        language="java"
        message="An abstract class should have a Logger initialized as 'protected final Logger logger = LogManager.getLogger(getClass());' "
        class="net.sourceforge.pmd.lang.rule.xpath.XPathRule">
    <priority>5</priority>
    <properties>
      <property name="xpath">
        <value>
          //ClassBody/FieldDeclaration
            [
              ../..[pmd-java:modifiers()='abstract']
                and
              ClassType[@SimpleName='Logger']
                and
              VariableDeclarator/VariableId/@Name!='logger'
            ]
        </value>
      </property>
    </properties>
  </rule-->

  <rule name="MCR.Singleton.MethodModifiers"
        language="java"
        message="A method named 'getInstance' should be static"
        class="net.sourceforge.pmd.lang.rule.xpath.XPathRule">
    <priority>4</priority>
    <properties>
      <property name="xpath">
        <value>
          //MethodDeclaration
            [
              @Name='getInstance'
                and
              not(ModifierList/Annotation/ClassType[pmd-java:typeIs('java.lang.Deprecated')])
            ]
            [
              not(pmd-java:modifiers()='static')
            ]
        </value>
      </property>
    </properties>
  </rule>

  <rule name="MCR.Singleton.MethodReturnType"
        language="java"
        message="A method named 'getInstance' should return an instance of the enclosing class"
        class="net.sourceforge.pmd.lang.rule.xpath.XPathRule">
    <priority>4</priority>
    <properties>
      <property name="xpath">
        <value>
          //MethodDeclaration
            [
              @Name='getInstance'
                and
              not(ModifierList/Annotation/ClassType[pmd-java:typeIs('java.lang.Deprecated')])
            ]
            [
              not(ClassType[pmd-java:typeIs(../../../@CanonicalName)])
            ]
        </value>
      </property>
    </properties>
  </rule>

  <rule name="MCR.Singleton.ClassModifiers"
        language="java"
        message="A singleton class (with method named 'getInstance') should be final"
        class="net.sourceforge.pmd.lang.rule.xpath.XPathRule">
    <priority>4</priority>
    <properties>
      <property name="xpath">
        <value>
          //MethodDeclaration
            [
              @Name='getInstance'
                and
              not(ModifierList/Annotation/ClassType[pmd-java:typeIs('java.lang.Deprecated')])
            ]
            [
              not(../..[pmd-java:modifiers()='final'])
            ]
        </value>
      </property>
    </properties>
  </rule>

  <rule name="MCR.Singleton.PrivateConstructor"
        language="java"
        message="A singleton class with (method named 'getInstance') should have a private constructor"
        class="net.sourceforge.pmd.lang.rule.xpath.XPathRule">
    <priority>4</priority>
    <properties>
      <property name="xpath">
        <value>
          //MethodDeclaration
            [
              @Name='getInstance'
                and
              not(ModifierList/Annotation/ClassType[pmd-java:typeIs('java.lang.Deprecated')])
            ]
            [
              not(../ConstructorDeclaration[pmd-java:modifiers()='private'])
            ]
        </value>
      </property>
    </properties>
  </rule>

  <rule name="MCR.Singleton.NonPrivateConstructors"
        language="java"
        message="A singleton class with (method named 'getInstance') should only have a private constructors"
        class="net.sourceforge.pmd.lang.rule.xpath.XPathRule">
    <priority>4</priority>
    <properties>
      <property name="xpath">
        <value>
          //MethodDeclaration
            [
              @Name='getInstance'
                and
              not(ModifierList/Annotation/ClassType[pmd-java:typeIs('java.lang.Deprecated')])
            ]
            [
              ../ConstructorDeclaration[not(deep-equal(pmd-java:modifiers(),('private')))]
            ]
        </value>
      </property>
    </properties>
  </rule>

  <rule name="MCR.SerialVersionUid.ModifiersAndType"
        language="java"
        message="The serialVersionUID should have modifiers private static final and type long"
        class="net.sourceforge.pmd.lang.rule.xpath.XPathRule">
    <priority>4</priority>
    <properties>
      <property name="xpath">
        <value>
          <![CDATA[
            //ClassBody/FieldDeclaration
              [
                VariableDeclarator/VariableId[@Name='serialVersionUID']
              ]
              [
                not(
                  deep-equal(pmd-java:modifiers(), ('private','static','final'))
                    and
                  PrimitiveType[@Kind='long']
                )
              ]
          ]]>
        </value>
      </property>
    </properties>
  </rule>

  <rule name="MCR.SerialVersionUid.Annotation"
        language="java"
        message="The serialVersionUID should be annotated with @java.io.Serial"
        class="net.sourceforge.pmd.lang.rule.xpath.XPathRule">
    <priority>4</priority>
    <description>
      Field should look like this:

      @Serial
      private static final long serialVersionUID = 1L;
    </description>
    <properties>
      <property name="xpath">
        <value>
          <![CDATA[
            //ClassBody/FieldDeclaration
              [
                VariableDeclarator/VariableId[@Name='serialVersionUID']
              ]
              [
                not(ModifierList/Annotation/ClassType[pmd-java:typeIs('java.io.Serial')])
              ]
          ]]>
        </value>
      </property>
    </properties>
  </rule>

  <rule name="MCR.SerialVersionUid.Value"
        language="java"
        message="The serialVersionUID should have literal value '1L'"
        class="net.sourceforge.pmd.lang.rule.xpath.XPathRule">
    <priority>4</priority>
    <description>
      Field should look like this:

      @Serial
      private static final long serialVersionUID = 1L;
    </description>
    <properties>
      <property name="xpath">
        <value>
          <![CDATA[
            //ClassBody/FieldDeclaration
              [
                VariableDeclarator/VariableId[@Name='serialVersionUID']
              ]
              [
                not(VariableDeclarator/NumericLiteral[@Image='1L'])
              ]
          ]]>
        </value>
      </property>
    </properties>
  </rule>

  <rule name="MCR.ResourceResolver"
        language="java"
        message="Resources should be accessed using MCRResourceResolver or MCRResourceHelper"
        class="net.sourceforge.pmd.lang.rule.xpath.XPathRule">
    <description>
      Accessing resources directly via Class, ClassLoader or ServletContext should only be done
      - in classes that are part of the setup of the MyCoRe application (e.g. MCRConfigurationInputStream, MCRComponent),
      - in classes that are used by MCRResourceResolver (e.g. MCRResourceProvider, MCRResourceLocator) or
      - in rare cases where module specific files need to be accessed (e.g. MCRCoreVersion accessing git.properties).
      Otherwise, MCRResourceResolver or MCRResourceHelper should be used.
    </description>
    <priority>1</priority>
    <properties>
      <property name="xpath">
        <value>
          <![CDATA[
            //(MethodCall|MethodReference)
              [*[position() = 1 and pmd-java:typeIs('java.lang.Class')]]
              [@MethodName=(
                'getResource',
                'getResourceAsStream'
              )]
              |
            //(MethodCall|MethodReference)
              [*[position() = 1 and pmd-java:typeIs('java.lang.ClassLoader')]]
              [@MethodName=(
                'resources',
                'getResource',
                'getResources',
                'getResourceAsStream'
              )]
              |
            //(MethodCall|MethodReference)
              [*[position() = 1 and pmd-java:typeIs('jakarta.servlet.ServletContext')]]
              [@MethodName=(
                'getResource',
                'getResourcePaths',
                'getResourceAsStream'
              )]
          ]]>
        </value>
      </property>
    </properties>
  </rule>

  <rule name="MCR.ClassTools.Clone"
        language="java"
        message="MCRClassTools#clone should be called as MCRClassTools.clone(getClass(), super::clone) exactly"
        class="net.sourceforge.pmd.lang.rule.xpath.XPathRule">
    <description>
      MCRClassTools#clone is a helper function for top most classes in class hierarchies that implement Cloneable
      and expect every subclass to implement a proper clone method, i.e. to never throw a CloneNotSupportedException.
      It is meant to simplify and harmonize suppression of this exception in the method signatures of the clone-Method
      of such classes and needs to be called as MCRClassTools.clone(getClass(), super::clone) exactly
    </description>
    <priority>1</priority>
    <properties>
      <property name="xpath">
        <value>
          <![CDATA[
            //(MethodCall|MethodReference)
              [
                *[position() = 1 and pmd-java:typeIs('org.mycore.common.MCRClassTools')]
                  and
                @MethodName='clone'
              ]
              [
                 not(ArgumentList/*[1][name()='MethodCall' and @MethodName='getClass' and ArgumentList and count(*)=1])
                   or
                 not(ArgumentList/*[2][name()='MethodReference' and @MethodName='clone' and SuperExpression and count(*)=1])
              ]
          ]]>
        </value>
      </property>
    </properties>
  </rule>


  <!-- rule name="MCR.XSLT.ExcludeAllResultPrefixes"
    language="xml"
    message="XSLT 2.0 and 3.0 stylesheets should set exclude-result-prefixes='#all' to prevent unused namespaces output."
    class="net.sourceforge.pmd.lang.xml.rule.DomXPathRule">
    <description>
      When using XSLT 2.0 or 3.0, it is a best practice to use exclude-result-prefixes="#all"
      to ensure that only explicitly required namespaces are included in the result document.
    </description>
    <priority>1</priority>
    <properties>
      <property name="xpath">
        <value>
          <![CDATA[
            /*
              [
                namespace-uri()='http://www.w3.org/1999/XSL/Transform'
                  and
                local-name()='stylesheet'
                  and
                (@version='2.0' or @version='3.0')
              ]
              [
                not(@exclude-result-prefixes='#all')
              ]
          ]]>
        </value>
      </property>
    </properties>
  </rule -->

</ruleset>