checkstyle-configuration.xml

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

<!-- Adapted from https://github.com/checkstyle/checkstyle/blob/master/config/checkstyle_checks.xml -->
<module name="Checker">
    <property name="charset" value="UTF-8" />

    <property name="severity" value="error" />

    <!-- Miscellaneous -->
    <module name="NewlineAtEndOfFile" />

    <!-- Regexp -->
    <module name="RegexpMultiline" />
    <module name="RegexpMultiline">
        <property name="format" value="\r?\n[\t ]*\r?\n[\t ]*\r?\n" />
        <property name="fileExtensions" value="java,xml,properties" />
        <property name="message" value="Unnecessary consecutive newlines" />
    </module>
    <module name="RegexpMultiline">
        <property name="format" value="/\*\*\W+\* +\p{javaLowerCase}" />
        <property name="fileExtensions" value="java" />
        <property name="message"
                value="First sentence in a comment should start with a capital letter" />
    </module>
    <module name="RegexpSingleline">
        <property name="format" value="\s+$" />
        <property name="minimum" value="0" />
        <property name="maximum" value="0" />
    </module>
    <module name="RegexpSingleline">
        <property name="format" value="/\*\* +\p{javaLowerCase}" />
        <property name="fileExtensions" value="java" />
        <property name="message"
                value="First sentence in a comment should start with a capital letter" />
    </module>
    <!--
     Links to .dtd files should start with "/", "http://" or "https://",
     otherwise they will be broken after archiving the documentation.
     See https://github.com/checkstyle/checkstyle/issues/7340 for details.
    -->
    <module name="RegexpSingleline">
        <property name="format" value="href=&quot;(?!\/|https?:\/\/).*?\.dtd&quot;" />
        <property name="fileExtensions" value="xml, vm" />
        <property name="message"
                value="Relative links to DTD files are prohibited. Please use absolute path or uri instead." />
    </module>
    <module name="RegexpOnFilename" />
    <module name="RegexpOnFilename">
        <property name="folderPattern" value="[\\/]src[\\/]\w+[\\/]java[\\/]" />
        <property name="fileNamePattern" value="\.java$" />
        <property name="match" value="false" />
        <message
                key="regexp.filepath.mismatch"
                value="Only java files should be located in the ''src/*/java'' folders." />
    </module>
    <module name="RegexpOnFilename">
        <property name="folderPattern" value="[\\/]src[\\/]test[\\/]java[\\/]" />
        <property name="fileNamePattern" value="^((\w+Test)|(Abstract\w+)|(Fake\w+))\.java$" />
        <property name="match" value="false" />
        <message
                key="regexp.filepath.mismatch"
                value="All files in the ''src/test/java'' folder should be named ''*Test.java'' or ''Abstract*.java''." />
    </module>
    <module name="RegexpMultiline">
        <property name="format" value="\{\n\n" />
        <property name="message" value="First line after opening a scope may not be blank." />
    </module>
    <module name="RegexpMultiline">
        <property name="format" value="\n\n[ ]*\}" />
        <property name="message" value="Last line before closing a scope may not be blank." />
    </module>

    <!-- Whitespace -->
    <module name="FileTabCharacter">
        <property name="eachLine" value="false" />
		<!-- All file extensions -->
        <property name="fileExtensions" value="" />
    </module>

    <module name="TreeWalker">
        <property name="tabWidth" value="4" />

        <!-- Annotations -->
        <module name="AnnotationLocation">
            <property name="id" value="AnnotationLocationMostCases" />
            <property name="tokens" value="CLASS_DEF, INTERFACE_DEF, ENUM_DEF, METHOD_DEF, CTOR_DEF" />
        </module>
        <module name="AnnotationLocation">
            <property name="id" value="AnnotationLocationVariables" />
            <property name="tokens" value="VARIABLE_DEF" />
            <property name="allowSamelineMultipleAnnotations" value="true" />
        </module>
        <module name="AnnotationLocation">
            <property name="tokens" value="ANNOTATION_DEF" />
            <property name="tokens" value="ANNOTATION_FIELD_DEF" />
            <property name="tokens" value="PACKAGE_DEF" />
            <property name="tokens" value="ENUM_CONSTANT_DEF" />
            <property name="tokens" value="VARIABLE_DEF" />
            <property name="allowSamelineSingleParameterlessAnnotation" value="false" />
        </module>
        <module name="AnnotationOnSameLine">
            <!-- we can not use it as it conflicts with AnnotationLocation -->
            <property name="severity" value="ignore" />
            <property name="tokens" value="METHOD_DEF" />
            <property name="tokens" value="CTOR_DEF" />
            <property name="tokens" value="TYPECAST" />
            <property name="tokens" value="DOT" />
            <property name="tokens" value="CLASS_DEF" />
            <property name="tokens" value="ENUM_DEF" />
            <property name="tokens" value="INTERFACE_DEF" />
            <property name="tokens" value="TYPE_ARGUMENT" />
            <property name="tokens" value="ANNOTATION_DEF" />
            <property name="tokens" value="LITERAL_NEW" />
            <property name="tokens" value="LITERAL_THROWS" />
            <property name="tokens" value="VARIABLE_DEF" />
            <property name="tokens" value="PARAMETER_DEF" />
            <property name="tokens" value="IMPLEMENTS_CLAUSE" />
            <property name="tokens" value="ANNOTATION_FIELD_DEF" />
        </module>
        <module name="AnnotationUseStyle">
            <property name="trailingArrayComma" value="always"/>
        </module>
        <module name="MissingDeprecated" />
        <module name="MissingOverride" />
        <module name="PackageAnnotation" />
        <module name="SuppressWarningsHolder" />

        <!-- Block Checks -->
        <module name="EmptyBlock">
            <property name="tokens" value="ARRAY_INIT" />
            <property name="tokens" value="INSTANCE_INIT" />
            <property name="tokens" value="LITERAL_CASE" />
            <property name="tokens" value="LITERAL_CATCH" />
            <property name="tokens" value="LITERAL_DEFAULT" />
            <property name="tokens" value="LITERAL_DO" />
            <property name="tokens" value="LITERAL_ELSE" />
            <property name="tokens" value="LITERAL_FINALLY" />
            <property name="tokens" value="LITERAL_FOR" />
            <property name="tokens" value="LITERAL_IF" />
            <property name="tokens" value="LITERAL_SWITCH" />
            <property name="tokens" value="LITERAL_SYNCHRONIZED" />
            <property name="tokens" value="LITERAL_TRY" />
            <property name="tokens" value="LITERAL_WHILE" />
            <property name="tokens" value="STATIC_INIT" />
            <property name="option" value="text" />
        </module>
        <module name="EmptyCatchBlock">
            <property name="exceptionVariableName" value="ignored" />
        </module>
        <module name="LeftCurly">
            <property name="option" value="nl" />
        </module>
        <module name="NeedBraces">
            <property name="tokens" value="LITERAL_DO" />
            <property name="tokens" value="LITERAL_ELSE" />
            <property name="tokens" value="LITERAL_FOR" />
            <property name="tokens" value="LITERAL_IF" />
            <property name="tokens" value="LITERAL_WHILE" />
            <property name="tokens" value="LITERAL_CASE" />
            <property name="tokens" value="LITERAL_DEFAULT" />
        </module>
        <module name="RightCurly">
            <property name="tokens" value="METHOD_DEF" />
            <property name="tokens" value="CTOR_DEF" />
            <property name="tokens" value="CLASS_DEF" />
            <property name="tokens" value="INSTANCE_INIT" />
            <property name="tokens" value="LITERAL_FOR" />
            <property name="tokens" value="STATIC_INIT" />
            <property name="tokens" value="LITERAL_WHILE" />
            <property name="tokens" value="LITERAL_CATCH" />
            <property name="tokens" value="LITERAL_ELSE" />
            <property name="tokens" value="LITERAL_FINALLY" />
            <property name="tokens" value="LITERAL_IF" />
            <property name="tokens" value="LITERAL_TRY" />
            <property name="tokens" value="ANNOTATION_DEF" />
            <property name="tokens" value="ENUM_DEF" />
            <property name="option" value="alone" />
        </module>
        <module name="RightCurly">
            <property name="tokens" value="LITERAL_DO" />
            <property name="option" value="same" />
        </module>

        <!-- Class Design -->
        <module name="FinalClass" />
        <module name="HideUtilityClassConstructor" />
        <module name="InnerTypeLast" />
        <!-- Effective Java Item 17 - Use interfaces only to define types -->
        <module name="InterfaceIsType" />
        <module name="MutableException" />
        <module name="OneTopLevelClass" />
        <module name="VisibilityModifier">
            <property
                    name="ignoreAnnotationCanonicalNames"
                    value="org.junit.Rule, org.junit.jupiter.api.io.TempDir" />
            <property name="protectedAllowed" value="true" />
        </module>

        <!-- Coding -->
        <module name="ArrayTrailingComma" />
        <module name="AvoidNoArgumentSuperConstructorCall" />
        <module name="CovariantEquals" />
        <module name="DeclarationOrder" />
        <module name="DefaultComesLast" />
        <module name="EmptyStatement" />
        <!--This check throws a NPE inside CheckStyle-->
        <!--<module name="EqualsAvoidNull" />-->
        <!-- Effective Java Item 8 - Always override hashCode when you override equals -->
        <module name="EqualsHashCode" />
        <module name="ExplicitInitialization" />
        <module name="FallThrough" />
        <module name="HiddenField">
            <property name="ignoreConstructorParameter" value="true" />
            <property name="ignoreSetter" value="true" />
            <property name="setterCanReturnItsClass" value="true" />
            <property name="severity" value="warning" />
        </module>
        <module name="IllegalCatch">
            <property name="illegalClassNames" value="java.lang.Error" />
            <property name="illegalClassNames" value="java.lang.NullPointerException" />
            <property name="illegalClassNames" value="java.lang.Throwable" />
        </module>
        <!-- Effective Java Item 4 - Avoid creating duplicate objects -->
        <module name="IllegalInstantiation">

            <property name="classes" value="antlr.ANTLRException" />
            <property name="classes" value="antlr.RecognitionException" />
            <property name="classes" value="antlr.TokenStreamException" />
            <property name="classes" value="antlr.TokenStreamRecognitionException" />
            <property name="classes" value="java.lang.Boolean" />
            <property name="classes" value="java.lang.Byte" />
            <property name="classes" value="java.lang.Character" />
            <property name="classes" value="java.lang.Integer" />
            <property name="classes" value="java.lang.Long" />
            <property name="classes" value="java.lang.Short" />
            <property name="classes" value="java.lang.StringBuffer" />
            <property name="classes" value="java.util.Timer" />
            <property name="classes" value="java.util.TimerTask" />
            <property name="classes" value="org.apache.commons.beanutils.ConversionException" />
            <property name="classes" value="org.xml.sax.SAXException" />
            <property name="classes" value="org.xml.sax.SAXParseException" />
        </module>
        <module name="IllegalThrows" />
        <module name="IllegalToken">
            <property name="tokens" value="LABELED_STAT" />
            <property name="tokens" value="LITERAL_NATIVE" />
            <property name="tokens" value="LITERAL_VOLATILE" />
            <property name="tokens" value="LITERAL_ASSERT" />
        </module>
        <module name="IllegalTokenText">
            <property name="tokens" value="STRING_LITERAL" />
            <property name="format" value="^(US-ASCII|ISO-8859-1|UTF-8|UTF-16BE|UTF-16LE|UTF-16)$" />
            <property name="ignoreCase" value="true" />
        </module>
        <module name="IllegalTokenText">
            <property name="tokens" value="STRING_LITERAL, CHAR_LITERAL" />
            <property
                    name="format"
                    value="\\u00(09|0(a|A)|0(c|C)|0(d|D)|22|27|5(C|c))|\\(0(10|11|12|14|15|42|47)|134)" />
            <property
                    name="message"
                    value="Consider using special escape sequence instead of octal value or Unicode escaped value." />
        </module>
        <module name="IllegalType">
            <property name="illegalClassNames"
                    value="
                        java.util.HashSet, HashSet,
                        java.util.LinkedHashMap, LinkedHashMap,
                        java.util.TreeMap, TreeMap,
                        java.util.HashMap, HashMap,
                        java.util.LinkedHashSet, LinkedHashSet,
                        java.util.TreeSet, TreeSet,
                        java.lang.StringBuffer, StringBuffer," />
        </module>
        <module name="InnerAssignment" />
        <module name="MissingSwitchDefault" />
        <module name="ModifiedControlVariable" />
        <module name="MultipleStringLiterals">
            <property name="ignoreStringsRegexp" value="^.{0,4}$" />
            <property name="severity" value="warning" />
        </module>
        <module name="MultipleVariableDeclarations" />
        <module name="NestedForDepth">
            <property name="max" value="2" />
        </module>
        <module name="NestedIfDepth">
            <property name="max" value="3" />
        </module>
        <module name="NestedTryDepth" />
        <module name="NoClone" />
        <!-- Effective Java: Avoid finalizers and cleaners -->
        <module name="NoFinalizer" />
        <module name="OneStatementPerLine" />
        <module name="OverloadMethodsDeclarationOrder" />
        <module name="PackageDeclaration" />
        <module name="ParameterAssignment" />
        <module name="RequireThis" />
        <module name="SimplifyBooleanExpression" />
        <module name="SimplifyBooleanReturn" />
        <module name="StringLiteralEquality" />
        <module name="SuperClone" />
        <module name="SuperFinalize" />
        <module name="UnnecessaryParentheses" />
        <module name="UnnecessarySemicolonAfterTypeMemberDeclaration" />
        <module name="UnnecessarySemicolonInEnumeration" />
        <module name="UnnecessarySemicolonInTryWithResources" />
        <module name="VariableDeclarationUsageDistance">
            <property name="severity" value="warning" />
        </module>

        <!-- Filters-->
        <!-- Tone down the checking for test code -->
        <module name="SuppressionXpathSingleFilter">
            <property name="files" value=".*[\\/]src[\\/](test|it)[\\/]" />
            <property name="checks" value="MagicNumber" />
        </module>
        <module name="SuppressionXpathSingleFilter">
            <property name="files" value=".*[\\/]src[\\/](test|it)[\\/]" />
            <property name="checks" value="MultipleStringLiterals" />
        </module>
        <module name="SuppressWithNearbyCommentFilter">
            <property name="commentFormat"
                    value="-@cs\[(\w{8,}(\|\w{8,})*)\] \w[\(\)\-\.\'\`\,\:\;\w ]{10,}" />
            <property name="checkFormat" value="$1" />
            <property name="influenceFormat" value="3" />
        </module>

        <!-- Imports -->
        <module name="AvoidStarImport">
            <property name="allowStaticMemberImports" value="true" />
        </module>
        <module name="AvoidStaticImport">
            <property name="excludes" value="org.fusesource.jansi.Ansi.*" />
            <property name="excludes" value="org.fusesource.jansi.Ansi.Color.*" />
            <property name="excludes" value="org.hamcrest.CoreMatchers.*" />
            <property name="excludes" value="org.hamcrest.MatcherAssert.*" />
            <property name="excludes" value="org.hamcrest.Matchers.*" />
            <property name="excludes" value="org.junit.Assert.*" />
            <property name="excludes" value="org.junit.Assume.*" />
        </module>
        <module name="CustomImportOrder">
            <property
                    name="customImportOrderRules"
                    value="STANDARD_JAVA_PACKAGE###SPECIAL_IMPORTS###THIRD_PARTY_PACKAGE###STATIC" />
            <property name="standardPackageRegExp" value="^java\." />
            <property name="specialImportsRegExp" value="^javax\." />
            <property name="sortImportsInGroupAlphabetically" value="true" />
            <property name="separateLineBetweenGroups" value="true" />
        </module>
        <module name="IllegalImport" />
        <module name="ImportOrder">
            <property name="groups" value="/^java\./,javax" />
            <property name="ordered" value="true" />
            <property name="separated" value="true" />
            <property name="option" value="bottom" />
            <property name="sortStaticImportsAlphabetically" value="true" />
        </module>
        <module name="RedundantImport" />
        <module name="UnusedImports">
            <property name="processJavadoc" value="true" />
        </module>

        <!-- Javadoc Comments -->
        <module name="AtclauseOrder" />
        <module name="InvalidJavadocPosition" />
        <module name="JavadocBlockTagLocation">
            <!-- default tags -->
            <property name="tags" value="author, deprecated, exception, hidden, param, provides" />
            <property name="tags" value="return, see, serial, serialData, serialField, since, throws" />
            <property name="tags" value="uses, version" />
            <!-- additional tags used in the project -->
            <property name="tags" value="noinspection" />
        </module>
        <module name="JavadocContentLocation" />
        <module name="JavadocMethod">
            <property name="validateThrows" value="true" />
        </module>
        <module name="JavadocParagraph">
            <property name="allowNewlineParagraph" value="false" />
        </module>
        <module name="JavadocTagContinuationIndentation" />
        <module name="MissingJavadocPackage" />
        <module name="NonEmptyAtclauseDescription" />
        <module name="SingleLineJavadoc" />

        <!-- Misc -->
        <module name="ArrayTypeStyle" />
        <module name="AvoidEscapedUnicodeCharacters">
            <property name="allowIfAllCharactersEscaped" value="true" />
        </module>
        <module name="CommentsIndentation" />
        <module name="DescendantToken" />
        <module name="Indentation">
            <property name="basicOffset" value="4" />
            <property name="braceAdjustment" value="0" />
            <property name="caseIndent" value="4" />
            <property name="throwsIndent" value="8" />
            <property name="lineWrappingIndentation" value="8" />
        </module>
        <module name="OuterTypeFilename" />
        <module name="TrailingComment" />
        <module name="UpperEll" />

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

        <!-- Naming Conventions -->
        <module name="ClassTypeParameterName">
            <!--Instead of single letter names like T, allow words like Type-->
            <property name="format" value="^[A-Z][a-zA-Z0-9]*$" />
        </module>
        <module name="ConstantName" />
        <module name="InterfaceTypeParameterName">
            <!--Instead of single letter names like T, allow words like Type-->
            <property name="format" value="^[A-Z][a-zA-Z0-9]*$" />
        </module>
        <module name="LocalFinalVariableName" />
        <module name="LocalVariableName">
            <property name="allowOneCharVarInForLoop" value="true" />
        </module>
        <module name="MemberName" />
        <module name="MethodName">
            <property name="format" value="^[a-z][a-zA-Z0-9_]*$" />
        </module>
        <!--Instead of single letter names like T, allow words like Type-->
        <module name="MethodTypeParameterName">
            <property name="format" value="^[A-Z][a-zA-Z0-9]*$" />
        </module>
        <module name="PackageName">
            <property name="format" value="^[a-z]+(\.[a-z][a-z0-9]*)*$" />
        </module>
        <module name="ParameterName">
            <property name="ignoreOverridden" value="true" />
        </module>
        <module name="LambdaParameterName" />
        <module name="CatchParameterName" />
        <module name="StaticVariableName" />
        <module name="TypeName">
            <property name="format" value="(^[A-Z][a-zA-Z0-9]*$)|(^[A-Z][a-zA-Z0-9_]*Test$)" />
        </module>

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

        <!-- Whitespace -->
        <module name="EmptyForInitializerPad" />
        <module name="EmptyForIteratorPad">
            <property name="option" value="space" />
        </module>
        <module name="EmptyLineSeparator">
            <property name="allowNoEmptyLineBetweenFields" value="true" />
            <property name="allowMultipleEmptyLinesInsideClassMembers" value="false" />
        </module>
        <module name="GenericWhitespace" />
        <module name="MethodParamPad" />
        <module name="NoLineWrap" />
        <module name="NoWhitespaceAfter">
            <property name="tokens" value="ARRAY_INIT" />
            <property name="tokens" value="AT" />
            <property name="tokens" value="BNOT" />
            <property name="tokens" value="DEC" />
            <property name="tokens" value="DOT" />
            <property name="tokens" value="INC" />
            <property name="tokens" value="LNOT" />
            <property name="tokens" value="UNARY_MINUS" />
            <property name="tokens" value="UNARY_PLUS" />
            <property name="tokens" value="ARRAY_DECLARATOR" />
            <property name="tokens" value="INDEX_OP" />
            <property name="tokens" value="METHOD_REF" />
        </module>
        <module name="NoWhitespaceBefore" />
        <module name="NoWhitespaceBefore">
            <property name="tokens" value="DOT" />
            <property name="tokens" value="METHOD_REF" />
            <property name="allowLineBreaks" value="true" />
        </module>
        <module name="OperatorWrap">
            <property name="tokens" value="QUESTION" />
            <property name="tokens" value="COLON" />
            <property name="tokens" value="EQUAL" />
            <property name="tokens" value="NOT_EQUAL" />
            <property name="tokens" value="DIV" />
            <property name="tokens" value="PLUS" />
            <property name="tokens" value="MINUS" />
            <property name="tokens" value="STAR" />
            <property name="tokens" value="MOD" />
            <property name="tokens" value="SR" />
            <property name="tokens" value="BSR" />
            <property name="tokens" value="GE" />
            <property name="tokens" value="GT" />
            <property name="tokens" value="SL" />
            <property name="tokens" value="LE" />
            <property name="tokens" value="LT" />
            <property name="tokens" value="BXOR" />
            <property name="tokens" value="BOR" />
            <property name="tokens" value="LOR" />
            <property name="tokens" value="BAND" />
            <property name="tokens" value="LAND" />
            <property name="tokens" value="TYPE_EXTENSION_AND" />
            <property name="tokens" value="LITERAL_INSTANCEOF" />
            <property name="tokens" value="METHOD_REF" />
            <property name="option" value="nl" />
        </module>
        <module name="OperatorWrap">
            <property name="tokens" value="ASSIGN" />
            <property name="tokens" value="DIV_ASSIGN" />
            <property name="tokens" value="PLUS_ASSIGN" />
            <property name="tokens" value="MINUS_ASSIGN" />
            <property name="tokens" value="STAR_ASSIGN" />
            <property name="tokens" value="MOD_ASSIGN" />
            <property name="tokens" value="SR_ASSIGN" />
            <property name="tokens" value="BSR_ASSIGN" />
            <property name="tokens" value="SL_ASSIGN" />
            <property name="tokens" value="BXOR_ASSIGN" />
            <property name="tokens" value="BOR_ASSIGN" />
            <property name="tokens" value="BAND_ASSIGN" />
            <property name="option" value="eol" />
        </module>
        <module name="ParenPad" />
        <module name="SeparatorWrap">
            <property name="id" value="SeparatorWrapNl" />
            <property name="tokens" value="DOT" />
            <property name="tokens" value="AT" />
            <property name="tokens" value="METHOD_REF" />
            <property name="option" value="nl" />
        </module>
        <module name="SeparatorWrap">
            <property name="id" value="SeparatorWrapEol" />
            <property name="tokens" value="COMMA" />
            <property name="tokens" value="RPAREN" />
            <property name="tokens" value="RBRACK" />
            <property name="tokens" value="ARRAY_DECLARATOR" />
            <property name="tokens" value="ELLIPSIS" />
            <property name="tokens" value="SEMI" />
            <property name="option" value="EOL" />
        </module>
        <module name="TypecastParenPad" />
        <module name="WhitespaceAfter" />
        <module name="WhitespaceAround">
            <property name="allowEmptyConstructors" value="true" />
            <property name="allowEmptyMethods" value="true" />
            <property name="allowEmptyTypes" value="true" />
            <property name="allowEmptyLoops" value="true" />
        </module>

        <module name="Indentation">
            <property name="lineWrappingIndentation" value="8" />
        </module>

        <!-- Miscellaneous other checks.                   -->
        <!-- See http://checkstyle.sf.net/config_misc.html -->

        <module name="Regexp">
            <property name="illegalPattern" value="true" />
            <property name="format" value="[’“”]" />
            <property name="message" value="Curly quotes aren't allowed." />
        </module>

        <module name="Regexp">
            <property name="illegalPattern" value="true" />
            <property name="format" value="[ ]+$" />
            <property name="message" value="Line has trailing spaces." />
        </module>

        <module name="RegexpSinglelineJava">
            <property name="ignoreComments" value="true" />

            <property
                    name="format"
                    value="System\.out\.println" />

            <property
                    name="message"
                    value="System.out.println." />
        </module>

        <module name="RegexpSinglelineJava">
            <property name="ignoreComments" value="true" />

            <property
                    name="format"
                    value="System\.err\.println" />

            <property
                    name="message"
                    value="System.err.println." />
        </module>
    </module>

</module>