checkstyle.xml

<?xml version="1.0"?>
<!DOCTYPE module PUBLIC
  "-//Checkstyle//DTD Checkstyle Configuration 1.3//EN"
  "https://checkstyle.org/dtds/configuration_1_3.dtd">

<!-- Checkstyle properties for XWiki projects. Note that checks that should always executed and never be excluded
     should be moved to checkstyle-blocker.xml -->
<module name="Checker">

  <!--
     ======================================================================================
       Checks that do not require a TreeWalker (sorted alphabetically)
     ======================================================================================
  -->

  <module name="FileLength"/>

  <module name="FileTabCharacter"/>

  <!-- We don't use Checkstyle's facility to check license headers since it's too limited for our needs.
       Instead we use http://code.google.com/p/maven-license-plugin/
  <module name="Header">
    <property name="headerFile" value="${checkstyle.header.file}"/>
    <property name="ignoreLines" value="4,5,6,7"/>
  </module>
  -->

  <module name="NewlineAtEndOfFile">
    <property name="fileExtensions" value="java, xml, js, css, vm"/>
  </module>

  <module name="NewlineAtEndOfFile">
    <property name="lineSeparator" value="crlf"/>
    <property name="fileExtensions" value="bat"/>
  </module>

  <module name="NewlineAtEndOfFile">
    <property name="lineSeparator" value="lf"/>
    <property name="fileExtensions" value="sh"/>
  </module>

  <!-- We'd like to use this one but there's no option to exclude our internal packages
  <module name="PackageHtml"/>
  -->

  <!-- No @author tags -->
  <module name="RegexpSingleline">
    <property name="format" value="@author"/>
    <property name="message" value="No @author tag allowed"/>
  </module>

  <!-- We cannot use this rule as it fails on our license headers, considering them as copy-pastes!
  <module name="StrictDuplicateCode"/>
  -->

  <!--  We actually have a lot of incomplete translations so we can't really afford this rule
  <module name="Translation"/>
   -->

  <module name="LineLength">
    <!-- @(\w+\.)+\w+::\w+\( stands for JSNI method calls: @my.package.MyClass::myMethod() -->
    <property name="ignorePattern" value="(@version|@see|@link|^import|@(\w+\.)+\w+::\w+\()"/>
    <property name="max" value="120"/>
    <property name="fileExtensions" value="java"/>
  </module>

  <!--
     ======================================================================================
       Checks that require a TreeWalker (sorted alphabetically)
     ======================================================================================
  -->
  <module name="TreeWalker">

    <module name="SuppressWarningsHolder" />

    <module name="SuppressWithNearbyCommentFilter">
      <property name="commentFormat" value="CHECKSTYLE:(\w+)"/>
      <property name="checkFormat" value="$1"/>
      <property name="influenceFormat" value="1"/>
    </module>

    <module name="SuppressWithNearbyCommentFilter">
      <property name="commentFormat" value="CHECKSTYLE:(\w+)\((\d+)\)"/>
      <property name="checkFormat" value="$1"/>
      <property name="influenceFormat" value="$2"/>
    </module>

    <!-- Note: for some checks we have defined a warning severity instead of the default error
         severity. This is because we'd like to make the build fail on error for those checks
         but there are errors to fix first -->

    <module name="AbstractClassName">
      <!-- We need to override the default format since by default classes ending with Factory are considered
           abstract and thus need to be defined with the "abstract" keyword. -->
      <property name="format" value="^Abstract.*$"/>
    </module>

    <module name="AnonInnerLength"/>

    <!--module name="ArrayTrailingComma"/-->

    <module name="ArrayTypeStyle"/>

    <!--module name="AvoidInlineConditionals"/-->

    <module name="AvoidNestedBlocks"/>

    <module name="AvoidStarImport"/>

    <module name="BooleanExpressionComplexity"/>

    <!-- This is a good metric but checkstyle doesn't allow to remove JDK's base classes
         from the new count thus making this check unusable IMO
    <module name="ClassDataAbstractionCoupling"/>
    -->

    <module name="ClassFanOutComplexity">
      <!--
          1) Default excludes (taken from https://github.com/checkstyle/checkstyle/blob/master/src/main/java/com/puppycrawl/tools/checkstyle/checks/metrics/AbstractClassCouplingCheck.java)
          2) Non XWiki excludes
          3) XWiki excludes
      -->
      <property name="excludedClasses" value="boolean, byte, char, double, float, int, long, short, void, Boolean, Byte,
        Character, Double, Float, Integer, Long, Short, Void, Object, Class, String, StringBuffer, StringBuilder,
        ArrayIndexOutOfBoundsException, Exception, RuntimeException, IllegalArgumentException, IllegalStateException,
        IndexOutOfBoundsException, NullPointerException, Throwable, SecurityException, UnsupportedOperationException,
        List, ArrayList, Deque, Queue, LinkedList, Set, HashSet, SortedSet, TreeSet, Map, HashMap, SortedMap, TreeMap,
        Override, Deprecated, SafeVarargs, SuppressWarnings, FunctionalInterface, Collection, EnumSet, LinkedHashMap,
        LinkedHashSet, Optional, OptionalDouble, OptionalInt, OptionalLong, DoubleStream, IntStream, LongStream, Stream,

        IOException, Collections, Arrays, ConcurrentHashMap, ConcurrentLinkedDeque, ConcurrentLinkedQueue, DelayQueue,
        FutureTask, LinkedBlockinDeque, LinkedBlockinQueue, Phaser, PriorityBlockingQueue, RejectedExecutionException,
        SynchronousQueue, Logger, LoggerFactory, StringUtils, FieldUtils, IOUtils, StringWriter, StringReader,
        ExceptionUtils, Inject, Provider, Named, Singleton, NavigableSet, Type, Priority,

        ComponentInstantiationStrategy, Unstable, Disposable, Initializable, InitializationException"/>
      <property name="excludedPackages"
        value="org.apache.maven.plugins.annotations, javax.annotation.concurrent, org.xwiki.component.annotation"/>
      <property name="max" value="21"/>
    </module>

    <module name="ClassTypeParameterName"/>

    <module name="ConstantName"/>

    <module name="CovariantEquals"/>

    <module name="CyclomaticComplexity"/>

    <module name="DeclarationOrder"/>

    <module name="DefaultComesLast"/>

    <!-- The default values for this one allow everything to pass. Unneeded.
    <module name="DescendantToken"/>
    -->

    <!--module name="DesignForExtension"/-->

    <module name="EmptyBlock">
      <property name="option" value="text"/>
    </module>

    <module name="EmptyForInitializerPad"/>

    <module name="EmptyForIteratorPad"/>

    <module name="EmptyStatement"/>

    <module name="EqualsHashCode"/>

    <module name="ExecutableStatementCount"/>

    <module name="ExplicitInitialization"/>

    <module name="FallThrough"/>

    <module name="FinalClass"/>

    <!--module name="FinalLocalVariable"/-->

    <!--module name="FinalParameters"/-->

    <!-- Avoid finalizers (this will not find violations that contain linebreaks) -->
    <module name="RegexpSinglelineJava">
      <property name="format" value="((public)|(protected))\s+void\s+finalize\(\s*\)"/>
      <property name="message" value="Avoid finalizers"/>
      <property name="ignoreComments" value="true"/>
    </module>

    <module name="HiddenField">
      <property name="tokens" value="VARIABLE_DEF"/>
    </module>

    <module name="HideUtilityClassConstructor"/>

    <!--module name="IllegalCatch"/-->

    <module name="IllegalImport"/>

    <module name="IllegalInstantiation">
      <property name="classes" value="java.lang.Boolean"/>
    </module>

    <module name="IllegalThrows"/>

    <!--module name="IllegalToken"/-->

    <!--module name="IllegalTokenText"/-->

    <module name="IllegalType">
      <!-- Disable CLASS_DEF introduced in Checkstyle 8.15 -->
      <!-- TODO: discuss if we want to enable it or not -->
      <property name="tokens"
        value="ANNOTATION_FIELD_DEF, INTERFACE_DEF, METHOD_CALL, METHOD_DEF, METHOD_REF, PARAMETER_DEF, VARIABLE_DEF"/>
    </module>

    <!--module name="ImportControl"/-->

    <!--module name="ImportOrder"/-->

    <module name="Indentation"/>

    <module name="InnerAssignment"/>

    <!--module name="InterfaceIsType"/-->

    <module name="JavadocMethod">
      <property name="accessModifiers" value="public"/>
    </module>

    <module name="MissingJavadocMethod"/>
    <module name="MissingJavadocType"/>

    <module name="JavadocStyle">
      <!-- Disabled since it's buggy, see
           https://forum.xwiki.org/t/disable-the-html-check-from-the-javadocstyle-rule/9513 -->
      <property name="checkHtml" value="false"/>
    </module>

    <module name="JavadocType">
      <property name="scope" value="public"/>
      <property name="versionFormat" value="\$Id.*\$"/>
    </module>

    <module name="JavadocVariable">
      <property name="scope" value="public"/>
    </module>

    <module name="JavaNCSS"/>

    <module name="LeftCurly">
      <property name="option" value="nl"/>
      <property name="tokens"
        value="ANNOTATION_DEF,CLASS_DEF,CTOR_DEF,ENUM_DEF,INTERFACE_DEF,METHOD_DEF"/>
    </module>

    <module name="LocalFinalVariableName"/>

    <module name="LocalVariableName"/>

    <!--module name="MagicNumber"/-->

    <module name="MemberName"/>

    <module name="MethodLength"/>

    <!-- Allow for UI methods generated by idea -->
    <module name="MethodName">
      <property name="format" value="^[a-z][a-zA-Z0-9]*$|^\$\$\$setupUI\$\$\$$"/>
    </module>

    <module name="MethodParamPad"/>

    <!--module name="MissingCtor"/-->

    <module name="MissingSwitchDefault"/>

    <module name="ModifiedControlVariable"/>

    <module name="ModifierOrder"/>

    <module name="MultipleStringLiterals">
      <property name="ignoreStringsRegexp" value='^("")|("[0-9]")|(" ")|("\]")$'/>
    </module>

    <module name="MultipleVariableDeclarations"/>

    <module name="MutableException"/>

    <module name="NeedBraces"/>

    <module name="NestedIfDepth">
      <property name="max" value="2"/>
    </module>

    <module name="NestedTryDepth"/>

    <module name="NoWhitespaceAfter">
      <property name="tokens" value="BNOT, DEC, DOT, INC, LNOT, UNARY_MINUS, UNARY_PLUS"/>
    </module>

    <module name="NoWhitespaceBefore"/>

    <module name="NPathComplexity"/>

    <module name="OperatorWrap"/>

    <module name="PackageDeclaration"/>

    <module name="PackageName"/>

    <module name="ParameterAssignment"/>

    <module name="ParameterName"/>

    <module name="ParameterNumber"/>

    <module name="ParenPad"/>

    <module name="RedundantImport"/>

    <module name="RedundantModifier"/>

    <!-- No direct printing to System.out or System.err -->
    <module name="RegexpSinglelineJava">
      <!-- . matches any character, so we need to
           escape it and use \. to match dots. -->
      <property name="format" value="System\.(out|err)\."/>
      <property name="ignoreComments" value="true"/>
    </module>

    <!--module name="Regexp"/-->

    <!--module name="RegexpHeader"/-->

    <!--module name="RequireThis">
      <property name="checkMethods" value="false"/>
    </module-->

    <!--module name="RequiredRegexp"/-->

    <!-- Increasing the maximum number of allowed return statements, as otherwise
         the code will simply use workarounds to hide the same amount of exit points. -->
    <module name="ReturnCount">
      <property name="max" value="5"/>
      <property name="maxForVoid" value="5"/>
    </module>

    <module name="RightCurly"/>

    <module name="SimplifyBooleanExpression"/>

    <module name="SimplifyBooleanReturn"/>

    <module name="StaticVariableName"/>

    <module name="StringLiteralEquality"/>

    <!-- We allow clone() implementations that don't call super.clone(), since
         some of our classes have this call nested in another method. -->
    <!--<module name="SuperClone"/>-->

    <module name="SuperFinalize"/>

    <!--module name="ThrowsCount"-->

    <module name="TodoComment">
      <property name="severity" value="warning"/>
      <property name="format" value="TODO"/>
    </module>
    <module name="TodoComment">
      <property name="severity" value="warning"/>
      <property name="format" value="FIXME"/>
    </module>
    <module name="TodoComment">
      <property name="severity" value="warning"/>
      <property name="format" value="@todo"/>
    </module>

    <module name="TrailingComment"/>

    <module name="TypeName"/>

    <module name="TypecastParenPad"/>

    <module name="UncommentedMain">
      <property name="excludedClasses" value=".*Main$"/>
    </module>

    <!--module name="UnnecessaryParentheses"/-->

    <module name="UnusedImports"/>

    <module name="UpperEll"/>

    <module name="VisibilityModifier">
      <property name="protectedAllowed" value="true"/>
      <property name="publicMemberPattern" value="^[a-z][a-zA-Z0-9]*$"/>
    </module>

    <module name="WhitespaceAfter"/>

    <module name="WhitespaceAround"/>

  </module>

  <module name="SuppressWarningsFilter" />
</module>