.checkstyle.xml

<?xml version="1.0"?>
<!DOCTYPE module PUBLIC
        "-//Puppy Crawl//DTD Check Configuration 1.3//EN"
        "http://www.puppycrawl.com/dtds/configuration_1_3.dtd">
<!--
 In order to be compatible with CodeClimate, we have to stay in sync with the version of Checkstyle that they are using.
 It doesn't seem to be updated much by default, but we can specify a channel, which is currently using 10.7.0.
 Check the links below to get up-to-date version information.
 https://github.com/codeclimate/codeclimate-checkstyle/branches/all (channel/ branches)
 https://docs.codeclimate.com/docs/checkstyle
 https://github.com/codeclimate/codeclimate-checkstyle/blob/master/bin/install-checkstyle.sh
-->

<module name="Checker">
    <property name="charset" value="UTF-8" />
    <property name="severity" value="warning" />
    <property name="fileExtensions" value="java" />

    <module name="SuppressWarningsFilter" />

    <module name="LineLength">
        <property name="max" value="120" />
        <property name="ignorePattern" value="^package.*|^import.*|a href|href|http://|https://|ftp://" />
    </module>

    <module name="TreeWalker">
        <module name="SuppressWarningsHolder" />
        <module name="SuppressionCommentFilter">
            <property name="offCommentFormat" value="CHECKSTYLE:OFF" />
            <property name="onCommentFormat" value="CHECKSTYLE:ON" />
        </module>

        <!-- The rules are kept by the groups defined in https://checkstyle.org/checks.html
             the checks are held alphabetically per group -->

        <!-- Annotations -->
        <module name="AnnotationLocation">
            <property name="tokens" value="CLASS_DEF, INTERFACE_DEF, ENUM_DEF, METHOD_DEF, CTOR_DEF" />
        </module>
        <module name="AnnotationLocation">
            <property name="tokens" value="VARIABLE_DEF" />
            <property name="allowSamelineMultipleAnnotations" value="true" />
        </module>
        <module name="AnnotationUseStyle" />
        <module name="MissingDeprecated" />

        <!-- Block checks -->
        <module name="AvoidNestedBlocks" />
        <module name="EmptyBlock">
            <property name="option" value="TEXT" />
            <property name="tokens" value="LITERAL_WHILE, LITERAL_TRY, LITERAL_FINALLY, LITERAL_DO, LITERAL_IF, LITERAL_ELSE, LITERAL_FOR, INSTANCE_INIT, STATIC_INIT, LITERAL_SWITCH, LITERAL_SYNCHRONIZED, LITERAL_CASE, LITERAL_DEFAULT" />
        </module>
        <module name="EmptyCatchBlock">
            <property name="exceptionVariableName" value="ignore|ignored" />
        </module>
        <module name="LeftCurly" />
        <module name="NeedBraces" />
        <module name="RightCurly">
            <property name="option" value="same" />
            <property name="tokens" value="LITERAL_TRY, LITERAL_CATCH, LITERAL_IF, LITERAL_ELSE, LITERAL_FOR, LITERAL_DO" />
        </module>
        <module name="RightCurly">
            <property name="option" value="alone" />
            <property name="tokens" value="LITERAL_FINALLY, CLASS_DEF, METHOD_DEF, CTOR_DEF, LITERAL_WHILE, STATIC_INIT, INSTANCE_INIT, ANNOTATION_DEF, ENUM_DEF, INTERFACE_DEF, RECORD_DEF, COMPACT_CTOR_DEF" />
        </module>

        <!-- Class design -->
        <module name="FinalClass" />
        <module name="HideUtilityClassConstructor" />
        <module name="InnerTypeLast" />
        <module name="InterfaceIsType" />
        <module name="MutableException" />
        <module name="OneTopLevelClass" />
        <module name="VisibilityModifier" />

        <!-- Coding -->
        <module name="AvoidDoubleBraceInitialization" />
        <module name="AvoidNoArgumentSuperConstructorCall" />
        <module name="CovariantEquals" />
        <module name="DeclarationOrder" />
        <module name="DefaultComesLast" />
        <module name="EmptyStatement" />
        <module name="EqualsAvoidNull" />
        <module name="EqualsHashCode" />
        <module name="FallThrough" />
        <module name="IllegalCatch" />
        <module name="IllegalInstantiation">
            <property name="classes" value="java.lang.Boolean, java.lang.Integer, java.lang.Long, java.lang.String"/>
        </module>
        <module name="IllegalThrows" />
        <module name="IllegalToken" />
        <module name="IllegalTokenText">
            <property name="tokens" value="STRING_LITERAL, CHAR_LITERAL" />
            <property name="format" value="\\u00(08|09|0(a|A)|0(c|C)|0(d|D)|22|27|5(C|c))|\\(0(10|11|12|14|15|42|47)|134)" />
            <property name="message" value="Avoid using corresponding octal or Unicode escape." />
        </module>
        <module name="IllegalType" />
        <module name="InnerAssignment" />
        <module name="MagicNumber" />
        <module name="MissingSwitchDefault" />
        <module name="ModifiedControlVariable" />
        <module name="MultipleVariableDeclarations" />
        <module name="NestedForDepth" />
        <module name="NestedIfDepth" />
        <module name="NestedTryDepth" />
        <module name="NoArrayTrailingComma" />
        <module name="NoClone" />
        <module name="NoEnumTrailingComma" />
        <module name="NoFinalizer" />
        <module name="OneStatementPerLine" />
        <module name="OverloadMethodsDeclarationOrder" />
        <module name="PackageDeclaration" />
        <module name="ParameterAssignment" />
        <module name="SimplifyBooleanExpression" />
        <module name="SimplifyBooleanReturn" />
        <module name="StringLiteralEquality" />
        <module name="UnnecessaryParentheses" />
        <module name="UnnecessarySemicolonAfterOuterTypeDeclaration" />
        <module name="UnnecessarySemicolonAfterTypeMemberDeclaration" />
        <module name="UnnecessarySemicolonInEnumeration" />
        <module name="UnnecessarySemicolonInTryWithResources" />
        <module name="UnusedLocalVariable" />
        <module name="VariableDeclarationUsageDistance" />

        <!-- Headers -->

        <!-- Imports -->
        <module name="AvoidStarImport" />
        <module name="RedundantImport" />
        <module name="UnusedImports" />

        <!-- Javadoc comments -->
        <module name="AtclauseOrder">
            <property name="tagOrder" value="@param, @return, @throws, @see, @deprecated" />
            <property name="target" value="CLASS_DEF, INTERFACE_DEF, ENUM_DEF, METHOD_DEF, CTOR_DEF, VARIABLE_DEF" />
        </module>
        <module name="InvalidJavadocPosition" />
        <module name="JavadocBlockTagLocation" />
        <module name="JavadocContentLocation" />
        <module name="JavadocMethod">
            <property name="accessModifiers" value="package" />
            <property name="tokens" value="METHOD_DEF, ANNOTATION_FIELD_DEF" />
        </module>
        <module name="JavadocMissingLeadingAsterisk" />
        <module name="JavadocMissingWhitespaceAfterAsterisk" />
        <module name="JavadocStyle" />
        <module name="JavadocTagContinuationIndentation" />
        <module name="JavadocType" />
        <module name="JavadocVariable">
            <property name="scope" value="package" />
        </module>
        <module name="MissingJavadocMethod">
            <property name="scope" value="package" />
            <property name="minLineCount" value="4" />
            <property name="allowedAnnotations" value="Override, Test" />
            <property name="tokens" value="METHOD_DEF, ANNOTATION_FIELD_DEF" />
        </module>
        <module name="MissingJavadocType">
            <property name="scope" value="package" />
        </module>
        <module name="NonEmptyAtclauseDescription" />
        <module name="RequireEmptyLineBeforeBlockTagGroup" />
        <module name="SingleLineJavadoc">
            <property name="ignoredTags" value="@return" />
        </module>

        <!-- Metrics -->
        <module name="BooleanExpressionComplexity">
            <property name="max" value="5" />
        </module>
        <module name="CyclomaticComplexity">
            <property name="max" value="15" />
        </module>
        <module name="JavaNCSS">
            <property name="methodMaximum" value="40" />
            <property name="classMaximum" value="1000" />
        </module>

        <!-- Miscellaneous -->
        <module name="ArrayTypeStyle" />
        <module name="AvoidEscapedUnicodeCharacters">
            <property name="allowEscapesForControlCharacters" value="true" />
            <property name="allowByTailComment" value="true" />
            <property name="allowNonPrintableEscapes" value="true" />
        </module>
        <module name="CommentsIndentation" />
        <module name="Indentation" />
        <module name="NoCodeInFile" />
        <module name="OuterTypeFilename" />
        <module name="TodoComment">
            <property name="format" value="(?i)(TODO|FIXME)" />
        </module>
        <module name="UpperEll" />

        <!-- Modifiers -->
        <module name="ModifierOrder" />
        <module name="RedundantModifier" />

        <!-- Naming conventions -->
        <module name="AbbreviationAsWordInName">
            <property name="ignoreFinal" value="false" />
            <property name="ignoreStatic" value="false" />
            <property name="allowedAbbreviationLength" value="0" />
        </module>
        <module name="CatchParameterName" />
        <module name="ClassTypeParameterName" />
        <module name="ConstantName" />
        <module name="InterfaceTypeParameterName" />
        <module name="LambdaParameterName" />
        <module name="LocalFinalVariableName" />
        <module name="LocalVariableName" />
        <module name="MemberName" />
        <module name="MethodName" />
        <module name="MethodTypeParameterName" />
        <module name="PackageName">
            <property name="format" value="^[a-z]+(\.[a-z][a-z0-9]*)*$" />
        </module>
        <module name="ParameterName" />
        <module name="StaticVariableName" />
        <module name="TypeName" />

        <!-- Regexp -->

        <!-- Size violations -->

        <!-- Whitespace -->
        <module name="EmptyLineSeparator">
            <property name="allowNoEmptyLineBetweenFields" value="true" />
        </module>
        <module name="GenericWhitespace" />
        <module name="MethodParamPad" />
        <module name="NoLineWrap" />
        <module name="NoWhitespaceAfter">
            <!-- Override to exclude ARRAY_INIT and to add LITERAL_SYNCHRONIZED, METHOD_REF -->
            <property name="tokens" value="AT, INC, DEC, UNARY_MINUS, UNARY_PLUS, BNOT, LNOT, DOT, ARRAY_DECLARATOR, INDEX_OP, LITERAL_SYNCHRONIZED, METHOD_REF" />
        </module>
        <module name="NoWhitespaceBefore">
            <!-- Override to exclude ELLIPSIS and to add METHOD_REF -->
            <property name="tokens" value="COMMA, SEMI, POST_INC, POST_DEC, LABELED_STAT, METHOD_REF" />
        </module>
        <module name="NoWhitespaceBeforeCaseDefaultColon" />
        <module name="OperatorWrap" />
        <module name="ParenPad" />
        <module name="SeparatorWrap">
            <property name="tokens" value="DOT" />
            <property name="option" value="nl" />
        </module>
        <module name="SeparatorWrap">
            <property name="tokens" value="COMMA" />
            <property name="option" value="EOL" />
        </module>
        <module name="SingleSpaceSeparator" />
        <module name="TypecastParenPad" />
        <module name="WhitespaceAfter" />
        <module name="WhitespaceAround" />
    </module>

    <module name="FileTabCharacter" />
    <module name="NewlineAtEndOfFile" />
</module>