checkstyle.xml

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

<!--
    Checkstyle configuration that checks based on the Google coding conventions from Google Java Style
    that can be found at https://google.github.io/styleguide/javaguide.html.

    Read the documentation at http://checkstyle.sf.net.

    Authors: Max Vetrenko, Ruslan Diachenko, Roman Ivanov.
 -->

<module name = "Checker">
  <property name="charset" value="UTF-8"/>

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

  <property name="fileExtensions" value="java, properties, xml"/>

  <module name="BeforeExecutionExclusionFileFilter">
    <property name="fileNamePattern" value="module\-info\.java$"/>
  </module>

  <!-- Checks for proper line length -->
  <module name="LineLength">
    <property name="max" value="100"/>
    <property name="ignorePattern" value="^package.*|^import.*|a href|href|http://|https://|ftp://"/>
  </module>

  <!-- Checks for whitespace -->
  <!-- See http://checkstyle.sf.net/config_whitespace.html -->
  <module name="FileTabCharacter">
    <property name="eachLine" value="true"/>
  </module>

  <!-- Do not allow @author tag in Javadoc -->
  <module name="RegexpSingleline">
    <property name="format" value="^\s*\*\s*@author" />
    <property name="minimum" value="0" />
    <property name="maximum" value="0" />
    <property name="message" value="Javadoc has illegal ''author'' tag." />
    <property name="fileExtensions" value="java" />
  </module>

  <module name="TreeWalker">
    <module name="OuterTypeFilename"/>
    <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="AvoidEscapedUnicodeCharacters">
      <property name="allowEscapesForControlCharacters" value="true"/>
      <property name="allowByTailComment" value="true"/>
      <property name="allowNonPrintableEscapes" value="true"/>
    </module>
    <module name="AvoidStarImport"/>
    <module name="OneTopLevelClass"/>
    <module name="NoLineWrap"/>
    <module name="EmptyBlock">
      <property name="option" value="TEXT"/>
      <property name="tokens" value="LITERAL_TRY, LITERAL_FINALLY, LITERAL_IF, LITERAL_ELSE, LITERAL_SWITCH"/>
    </module>
    <module name="NeedBraces">
      <property name="allowSingleLineStatement" value="true"/>
    </module>
    <module name="LeftCurly"/>
    <module name="RightCurly">
      <property name="id" value="RightCurlySame"/>
      <property name="tokens" value="LITERAL_TRY, LITERAL_CATCH, LITERAL_FINALLY, LITERAL_IF, LITERAL_ELSE, LITERAL_DO"/>
    </module>
    <module name="RightCurly">
      <property name="id" value="RightCurlyAlone"/>
      <property name="option" value="alone"/>
      <property name="tokens" value="CLASS_DEF, METHOD_DEF, CTOR_DEF, LITERAL_FOR, LITERAL_WHILE, STATIC_INIT, INSTANCE_INIT"/>
    </module>
    <module name="WhitespaceAround">
      <property name="allowEmptyConstructors" value="true"/>
      <property name="allowEmptyMethods" value="true"/>
      <property name="allowEmptyTypes" value="true"/>
      <property name="allowEmptyLoops" value="true"/>
      <message key="ws.notFollowed"
               value="WhitespaceAround: ''{0}'' is not followed by whitespace. Empty blocks may only be represented as '{}' when not part of a multi-block statement (4.1.3)"/>
      <message key="ws.notPreceded"
               value="WhitespaceAround: ''{0}'' is not preceded with whitespace."/>
    </module>
    <module name="OneStatementPerLine"/>
    <module name="MultipleVariableDeclarations"/>
    <module name="ArrayTypeStyle"/>
    <module name="MissingSwitchDefault"/>
    <module name="FallThrough"/>
    <module name="UpperEll"/>
    <module name="ModifierOrder"/>
    <module name="EmptyLineSeparator">
      <property name="allowNoEmptyLineBetweenFields" value="true"/>
    </module>
    <module name="SeparatorWrap">
      <property name="id" value="SeparatorWrapDot"/>
      <property name="tokens" value="DOT"/>
      <property name="option" value="nl"/>
    </module>
    <module name="SeparatorWrap">
      <property name="id" value="SeparatorWrapComma"/>
      <property name="tokens" value="COMMA"/>
      <property name="option" value="EOL"/>
    </module>
    <module name="SeparatorWrap">
      <!-- ELLIPSIS is EOL until https://github.com/google/styleguide/issues/258 -->
      <property name="id" value="SeparatorWrapEllipsis"/>
      <property name="tokens" value="ELLIPSIS"/>
      <property name="option" value="EOL"/>
    </module>
    <module name="SeparatorWrap">
      <!-- ARRAY_DECLARATOR is EOL until https://github.com/google/styleguide/issues/259 -->
      <property name="id" value="SeparatorWrapArrayDeclarator"/>
      <property name="tokens" value="ARRAY_DECLARATOR"/>
      <property name="option" value="EOL"/>
    </module>
    <module name="SeparatorWrap">
      <property name="id" value="SeparatorWrapMethodRef"/>
      <property name="tokens" value="METHOD_REF"/>
      <property name="option" value="nl"/>
    </module>
    <module name="PackageName">
      <property name="format" value="^[a-z]+(\.[a-z][a-z0-9]*)*$"/>
      <message key="name.invalidPattern"
               value="Package name ''{0}'' must match pattern ''{1}''."/>
    </module>
    <module name="TypeName">
      <message key="name.invalidPattern"
               value="Type name ''{0}'' must match pattern ''{1}''."/>
    </module>
    <module name="MemberName">
      <property name="format" value="^[a-z][a-z0-9][a-zA-Z0-9]*$"/>
      <message key="name.invalidPattern"
               value="Member name ''{0}'' must match pattern ''{1}''."/>
    </module>
    <module name="ParameterName">
      <property name="format" value="^[a-z]([a-z0-9][a-zA-Z0-9]*)?$"/>
      <message key="name.invalidPattern"
               value="Parameter name ''{0}'' must match pattern ''{1}''."/>
    </module>
    <module name="CatchParameterName">
      <property name="format" value="^[a-z]([a-z0-9][a-zA-Z0-9]*)?$"/>
      <message key="name.invalidPattern"
               value="Catch parameter name ''{0}'' must match pattern ''{1}''."/>
    </module>
    <module name="LocalVariableName">
      <property name="tokens" value="VARIABLE_DEF"/>
      <property name="format" value="^[a-z]([a-z0-9][a-zA-Z0-9]*)?$"/>
      <message key="name.invalidPattern"
               value="Local variable name ''{0}'' must match pattern ''{1}''."/>
    </module>
    <module name="ClassTypeParameterName">
      <property name="format" value="(^[A-Z][0-9]?)$|([A-Z][a-zA-Z0-9]*[T]$)"/>
      <message key="name.invalidPattern"
               value="Class type name ''{0}'' must match pattern ''{1}''."/>
    </module>
    <module name="MethodTypeParameterName">
      <property name="format" value="(^[A-Z][0-9]?)$|([A-Z][a-zA-Z0-9]*[T]$)"/>
      <message key="name.invalidPattern"
               value="Method type name ''{0}'' must match pattern ''{1}''."/>
    </module>
    <module name="InterfaceTypeParameterName">
      <property name="format" value="(^[A-Z][0-9]?)$|([A-Z][a-zA-Z0-9]*[T]$)"/>
      <message key="name.invalidPattern"
               value="Interface type name ''{0}'' must match pattern ''{1}''."/>
    </module>
    <module name="NoFinalizer"/>
    <module name="GenericWhitespace">
      <message key="ws.followed"
               value="GenericWhitespace ''{0}'' is followed by whitespace."/>
      <message key="ws.preceded"
               value="GenericWhitespace ''{0}'' is preceded with whitespace."/>
      <message key="ws.illegalFollow"
               value="GenericWhitespace ''{0}'' should followed by whitespace."/>
      <message key="ws.notPreceded"
               value="GenericWhitespace ''{0}'' is not preceded with whitespace."/>
    </module>
    <module name="Indentation">
      <property name="basicOffset" value="2"/>
      <property name="braceAdjustment" value="0"/>
      <property name="caseIndent" value="2"/>
      <property name="throwsIndent" value="4"/>
      <property name="lineWrappingIndentation" value="4"/>
      <property name="arrayInitIndent" value="2"/>
    </module>
    <module name="AbbreviationAsWordInName">
      <property name="ignoreFinal" value="false"/>
      <property name="allowedAbbreviationLength" value="4"/>
    </module>
    <module name="OverloadMethodsDeclarationOrder"/>
    <module name="VariableDeclarationUsageDistance"/>
    <module name="ImportOrder">
      <property name="groups" value="*,com,jakarta,java,javax,net,nl,org"/>
      <property name="ordered" value="true"/>
      <property name="separated" value="true"/>
      <property name="option" value="bottom"/>
      <property name="sortStaticImportsAlphabetically" value="true"/>
    </module>
    <module name="MethodParamPad"/>
    <module name="NoWhitespaceBefore">
      <property name="tokens" value="COMMA, SEMI, POST_INC, POST_DEC, DOT, ELLIPSIS, METHOD_REF"/>
      <property name="allowLineBreaks" value="true"/>
    </module>
    <module name="WhitespaceAfter"/>
    <module name="ParenPad"/>
    <module name="OperatorWrap">
      <property name="option" value="NL"/>
      <property name="tokens" value="BAND, BOR, BSR, BXOR, DIV, EQUAL, GE, GT, LAND, LE, LITERAL_INSTANCEOF, LOR, LT, MINUS, MOD, NOT_EQUAL, PLUS, QUESTION, SL, SR, STAR, METHOD_REF "/>
    </module>
    <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="NonEmptyAtclauseDescription"/>
    <module name="JavadocTagContinuationIndentation"/>
    <module name="SummaryJavadoc">
      <property name="forbiddenSummaryFragments" value="^@return the *|^This method returns |^This class |^A [{]@code [a-zA-Z0-9]+[}]( is a )"/>
    </module>
    <module name="JavadocParagraph"/>
    <module name="JavadocStyle">
      <property name="checkEmptyJavadoc" value="true"/>
    </module>
    <module name="AtclauseOrder">
      <property name="tagOrder" value="@param, @return, @throws, @see, @since, @deprecated"/>
      <property name="target" value="CLASS_DEF, INTERFACE_DEF, ENUM_DEF, METHOD_DEF, CTOR_DEF, VARIABLE_DEF"/>
    </module>
    <module name="JavadocType">
      <property name="scope" value="public"/>
    </module>
    <module name="JavadocMethod">
      <property name="accessModifiers" value="public"/>
      <property name="allowedAnnotations" value="Override, Test, BeforeEach, AfterEach, BeforeAll, AfterAll"/>
    </module>
    <module name="JavadocBlockTagLocation"/>
    <module name="JavadocMissingLeadingAsteriskCheck"/>
    <module name="JavadocMissingWhitespaceAfterAsterisk"/>
    <module name="MethodName">
      <property name="format" value="^[a-z][a-z0-9][a-zA-Z0-9_]*$"/>
      <message key="name.invalidPattern"
               value="Method name ''{0}'' must match pattern ''{1}''."/>
    </module>
    <module name="SingleLineJavadoc">
      <property name="ignoreInlineTags" value="false"/>
    </module>
    <module name="InvalidJavadocPosition"/>
    <module name="EmptyCatchBlock">
      <property name="exceptionVariableName" value="expected"/>
    </module>
    <module name="CommentsIndentation"/>
    <module name="UnnecessarySemicolonAfterTypeMemberDeclaration"/>
    <module name="UnnecessarySemicolonInEnumeration"/>
    <module name="UnnecessarySemicolonInTryWithResources"/>
  </module>
</module>