checkstyle-rules.xml

<?xml version="1.0"?>

<!--
  Licensed to the Apache Software Foundation (ASF) under one or more
  contributor license agreements.  See the NOTICE file distributed with
  this work for additional information regarding copyright ownership.
  The ASF licenses this file to You under the Apache License, Version 2.0
  (the "License"); you may not use this file except in compliance with
  the License.  You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
-->

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

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

    Checkstyle is very configurable. Be sure to read the documentation at
    http://checkstyle.org (or in your downloaded distribution).

    To completely disable a check, just comment it out or delete it from the file.
    To suppress certain violations please review suppression filters.

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

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

  <property name="fileExtensions" value="java, properties, xml"/>
  <!-- Excludes all 'module-info.java' files              -->
  <!-- See https://checkstyle.org/filefilters/beforeexecutionexclusionfilefilter.html -->
  <module name="BeforeExecutionExclusionFileFilter">
    <property name="fileNamePattern" value="module\-info\.java$"/>
  </module>
  <!-- https://checkstyle.org/filters/suppressionfilter.html -->
  <module name="SuppressionFilter">
    <property name="file" value="${org.checkstyle.google.suppressionfilter.config}"
           default="checkstyle-suppressions.xml" />
    <property name="optional" value="true"/>
  </module>

  <!-- Checks for whitespace                               -->
  <!-- https://checkstyle.org/checks/whitespace/filetabcharacter.html -->
  <module name="FileTabCharacter">
    <property name="eachLine" value="true"/>
  </module>

  <module name="LineLength">
    <property name="fileExtensions" value="java"/>
    <property name="max" value="140"/>
    <property name="ignorePattern" value="^package.*|^import.*|a href|href|http://|https://|ftp://"/>
  </module>

  <module name="TreeWalker">
    <!-- Import Checks. See: https://checkstyle.org/checks/imports/unusedimports.html -->
    <module name="UnusedImports"/>

    <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">
      <property name="tokens" value="PACKAGE_DEF, IMPORT, STATIC_IMPORT"/>
    </module>
    <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="tokens"
               value="LITERAL_DO, LITERAL_ELSE, LITERAL_FOR, LITERAL_IF, LITERAL_WHILE"/>
    </module>
    <module name="LeftCurly">
      <property name="tokens"
               value="ANNOTATION_DEF, CLASS_DEF, CTOR_DEF, ENUM_CONSTANT_DEF, ENUM_DEF,
                    INTERFACE_DEF, LAMBDA, LITERAL_CASE, LITERAL_CATCH, LITERAL_DEFAULT,
                    LITERAL_DO, LITERAL_ELSE, LITERAL_FINALLY, LITERAL_FOR, LITERAL_IF,
                    LITERAL_SWITCH, LITERAL_SYNCHRONIZED, LITERAL_TRY, LITERAL_WHILE, METHOD_DEF,
                    OBJBLOCK, STATIC_INIT, RECORD_DEF, COMPACT_CTOR_DEF"/>
    </module>
    <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, ANNOTATION_DEF, ENUM_DEF, INTERFACE_DEF, RECORD_DEF,
                    COMPACT_CTOR_DEF"/>
    </module>
    <module name="SuppressionXpathSingleFilter">
      <!-- suppression is required till https://github.com/checkstyle/checkstyle/issues/7541 -->
      <property name="id" value="RightCurlyAlone"/>
      <property name="query" value="//RCURLY[parent::SLIST[count(./*)=1]
                                     or preceding-sibling::*[last()][self::LCURLY]]"/>
    </module>
    <module name="WhitespaceAfter">
      <property name="tokens"
               value="COMMA, SEMI, TYPECAST, LITERAL_IF, LITERAL_ELSE,
                    LITERAL_WHILE, LITERAL_DO, LITERAL_FOR, DO_WHILE"/>
    </module>
    <module name="WhitespaceAround">
      <property name="allowEmptyConstructors" value="true"/>
      <property name="allowEmptyLambdas" value="true"/>
      <property name="allowEmptyMethods" value="true"/>
      <property name="allowEmptyTypes" value="true"/>
      <property name="allowEmptyLoops" value="true"/>
      <property name="ignoreEnhancedForColon" value="false"/>
      <property name="tokens"
               value="ASSIGN, BAND, BAND_ASSIGN, BOR, BOR_ASSIGN, BSR, BSR_ASSIGN, BXOR,
                    BXOR_ASSIGN, COLON, DIV, DIV_ASSIGN, DO_WHILE, EQUAL, GE, GT, LAMBDA, LAND,
                    LCURLY, LE, LITERAL_CATCH, LITERAL_DO, LITERAL_ELSE, LITERAL_FINALLY,
                    LITERAL_FOR, LITERAL_IF, LITERAL_RETURN, LITERAL_SWITCH, LITERAL_SYNCHRONIZED,
                    LITERAL_TRY, LITERAL_WHILE, LOR, LT, MINUS, MINUS_ASSIGN, MOD, MOD_ASSIGN,
                    NOT_EQUAL, PLUS, PLUS_ASSIGN, QUESTION, RCURLY, SL, SLIST, SL_ASSIGN, SR,
                    SR_ASSIGN, STAR, STAR_ASSIGN, LITERAL_ASSERT, TYPE_EXTENSION_AND"/>
      <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="tokens"
               value="PACKAGE_DEF, IMPORT, STATIC_IMPORT, CLASS_DEF, INTERFACE_DEF, ENUM_DEF,
                    STATIC_INIT, INSTANCE_INIT, METHOD_DEF, CTOR_DEF, VARIABLE_DEF, RECORD_DEF,
                    COMPACT_CTOR_DEF"/>
      <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/259 -->
      <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/258 -->
      <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]*)*$"/>
      <message key="name.invalidPattern"
             value="Package name ''{0}'' must match pattern ''{1}''."/>
    </module>
    <module name="TypeName">
      <property name="tokens" value="CLASS_DEF, INTERFACE_DEF, ENUM_DEF,
                    ANNOTATION_DEF, RECORD_DEF"/>
      <message key="name.invalidPattern"
             value="Type name ''{0}'' must match pattern ''{1}''."/>
    </module>
    <module name="MemberName">
      <property name="format" value="^[a-z][a-z0-9][a-zA-Z0-9]*$"/>
      <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]*)?$"/>
      <message key="name.invalidPattern"
             value="Parameter name ''{0}'' must match pattern ''{1}''."/>
    </module>
    <module name="LambdaParameterName">
      <property name="format" value="^[a-z]([a-z0-9][a-zA-Z0-9]*)?$"/>
      <message key="name.invalidPattern"
             value="Lambda parameter name ''{0}'' must match pattern ''{1}''."/>
    </module>
    <module name="CatchParameterName">
      <property name="format" value="^[a-z]([a-z0-9][a-zA-Z0-9]*)?$"/>
      <message key="name.invalidPattern"
             value="Catch parameter name ''{0}'' must match pattern ''{1}''."/>
    </module>
    <module name="LocalVariableName">
      <property name="format" value="^[a-z]([a-z0-9][a-zA-Z0-9]*)?$"/>
      <message key="name.invalidPattern"
             value="Local variable name ''{0}'' must match pattern ''{1}''."/>
    </module>
    <module name="PatternVariableName">
      <property name="format" value="^[a-z]([a-z0-9][a-zA-Z0-9]*)?$"/>
      <message key="name.invalidPattern"
             value="Pattern variable name ''{0}'' must match pattern ''{1}''."/>
    </module>
    <module name="ClassTypeParameterName">
      <property name="format" value="(^[A-Z][0-9]?)$|([A-Z][a-zA-Z0-9]*[T]$)"/>
      <message key="name.invalidPattern"
             value="Class type name ''{0}'' must match pattern ''{1}''."/>
    </module>
    <module name="RecordComponentName">
      <property name="format" value="^[a-z]([a-z0-9][a-zA-Z0-9]*)?$"/>
      <message key="name.invalidPattern"
               value="Record component name ''{0}'' must match pattern ''{1}''."/>
    </module>
    <module name="RecordTypeParameterName">
      <property name="format" value="(^[A-Z][0-9]?)$|([A-Z][a-zA-Z0-9]*[T]$)"/>
      <message key="name.invalidPattern"
               value="Record 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="MethodName">
      <property name="format" value="^[a-z][a-z0-9][a-zA-Z0-9_]*$"/>
      <message key="name.invalidPattern"
             value="Method name ''{0}'' must match pattern ''{1}''."/>
    </module>
    <module name="NoFinalizer"/>
    <module name="GenericWhitespace">
      <message key="ws.followed"
             value="GenericWhitespace ''{0}'' is followed by whitespace."/>
      <message key="ws.preceded"
             value="GenericWhitespace ''{0}'' is preceded with whitespace."/>
      <message key="ws.illegalFollow"
             value="GenericWhitespace ''{0}'' should followed by whitespace."/>
      <message key="ws.notPreceded"
             value="GenericWhitespace ''{0}'' is not preceded with whitespace."/>
    </module>
    <module name="Indentation">
      <property name="basicOffset" value="4"/>
      <property name="braceAdjustment" value="0"/>
      <property name="caseIndent" value="4"/>
      <property name="throwsIndent" value="8"/>
      <property name="lineWrappingIndentation" value="8"/>
      <property name="arrayInitIndent" value="4"/>
    </module>
    <module name="RegexpSinglelineJava">
      <property name="format" value="^\s+$"/>
      <property name="message" value="Line contains a whitespace indent only."/>
      <property name="ignoreComments" value="true"/>
    </module>
    <module name="AbbreviationAsWordInName">
      <property name="ignoreFinal" value="false"/>
      <property name="allowedAbbreviationLength" value="0"/>
      <property name="tokens"
               value="CLASS_DEF, INTERFACE_DEF, ENUM_DEF, ANNOTATION_DEF, ANNOTATION_FIELD_DEF,
                    PARAMETER_DEF, VARIABLE_DEF, METHOD_DEF, PATTERN_VARIABLE_DEF, RECORD_DEF,
                    RECORD_COMPONENT_DEF"/>
    </module>
    <module name="NoWhitespaceBeforeCaseDefaultColon"/>
    <module name="OverloadMethodsDeclarationOrder"/>
    <module name="CustomImportOrder">
      <property name="sortImportsInGroupAlphabetically" value="true"/>
      <property name="separateLineBetweenGroups" value="true"/>
      <property name="customImportOrderRules" value="STATIC###THIRD_PARTY_PACKAGE"/>
      <property name="tokens" value="IMPORT, STATIC_IMPORT, PACKAGE_DEF"/>
    </module>
    <module name="MethodParamPad">
      <property name="tokens"
               value="CTOR_DEF, LITERAL_NEW, METHOD_CALL, METHOD_DEF,
                    SUPER_CTOR_CALL, ENUM_CONSTANT_DEF, RECORD_DEF"/>
    </module>
    <module name="NoWhitespaceBefore">
      <property name="tokens"
               value="COMMA, SEMI, POST_INC, POST_DEC, DOT,
                    LABELED_STAT, METHOD_REF"/>
      <property name="allowLineBreaks" value="true"/>
    </module>
    <module name="ParenPad">
      <property name="tokens"
               value="ANNOTATION, ANNOTATION_FIELD_DEF, CTOR_CALL, CTOR_DEF, DOT, ENUM_CONSTANT_DEF,
                    EXPR, LITERAL_CATCH, LITERAL_DO, LITERAL_FOR, LITERAL_IF, LITERAL_NEW,
                    LITERAL_SWITCH, LITERAL_SYNCHRONIZED, LITERAL_WHILE, METHOD_CALL,
                    METHOD_DEF, QUESTION, RESOURCE_SPECIFICATION, SUPER_CTOR_CALL, LAMBDA,
                    RECORD_DEF"/>
    </module>
    <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,
                    TYPE_EXTENSION_AND "/>
    </module>
    <module name="AnnotationLocation">
      <property name="id" value="AnnotationLocationMostCases"/>
      <property name="tokens"
               value="CLASS_DEF, INTERFACE_DEF, ENUM_DEF, METHOD_DEF, CTOR_DEF,
                      RECORD_DEF, COMPACT_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="InvalidJavadocPosition"/>
    <module name="JavadocTagContinuationIndentation"/>
    <module name="SummaryJavadoc">
      <property name="forbiddenSummaryFragments"
               value="^@return the *|^This method returns |^A [{]@code [a-zA-Z0-9]+[}]( is a )"/>
    </module>
    <module name="JavadocParagraph"/>
    <module name="RequireEmptyLineBeforeBlockTagGroup"/>
    <module name="AtclauseOrder">
      <property name="tagOrder" value="@param, @return, @throws, @deprecated"/>
      <property name="target"
               value="CLASS_DEF, INTERFACE_DEF, ENUM_DEF, METHOD_DEF, CTOR_DEF, VARIABLE_DEF"/>
    </module>
    <module name="JavadocMethod">
      <property name="accessModifiers" value="public"/>
      <property name="allowMissingParamTags" value="true"/>
      <property name="allowMissingReturnTag" value="true"/>
      <property name="allowedAnnotations" value="Override, Test, ParameterizedTest, TestFactory, BeforeEach, BeforeAll, AfterEach, AfterAll"/>
      <property name="tokens" value="METHOD_DEF, CTOR_DEF, ANNOTATION_FIELD_DEF, COMPACT_CTOR_DEF"/>
    </module>
    <module name="MissingJavadocMethod">
      <property name="scope" value="public"/>
      <property name="minLineCount" value="2"/>
      <property name="allowedAnnotations" value="Override, Test, ParameterizedTest, TestFactory, BeforeEach, BeforeAll, AfterEach, AfterAll"/>
      <property name="tokens" value="METHOD_DEF, CTOR_DEF, ANNOTATION_FIELD_DEF, COMPACT_CTOR_DEF"/>
    </module>
    <module name="MissingJavadocType">
      <property name="scope" value="protected"/>
      <property name="tokens"
                value="CLASS_DEF, INTERFACE_DEF, ENUM_DEF,
                      RECORD_DEF, ANNOTATION_DEF"/>
      <property name="excludeScope" value="nothing"/>
    </module>
    <module name="SingleLineJavadoc"/>
    <module name="EmptyCatchBlock">
      <property name="exceptionVariableName" value="expected"/>
    </module>
    <module name="CommentsIndentation">
      <property name="tokens" value="SINGLE_LINE_COMMENT, BLOCK_COMMENT_BEGIN"/>
    </module>
    <!-- Comments should start with space -->
    <module name="TodoComment">
      <property name="id" value="CommentStartWithSpace"/>
      <property name="format" value="^(?!CHECKSTYLE:ON)(?!noinspection)(?!---)(?!===)([^\s\/*])"/>
      <message key="todo.match" value="Comment text should start with space."/>
    </module>
    <!-- https://checkstyle.org/filters/suppressionxpathfilter.html -->
    <module name="SuppressionXpathFilter">
      <property name="file" value="${org.checkstyle.google.suppressionxpathfilter.config}"
             default="checkstyle-xpath-suppressions.xml" />
      <property name="optional" value="true"/>
    </module>
    <!-- https://checkstyle.org/filters/suppressioncommentfilter.html -->
    <module name="SuppressionCommentFilter"/>
    <!-- https://checkstyle.org/checks/coding/packagedeclaration.html -->
    <module name="PackageDeclaration"/>
  </module>
  <module name="Header">
    <property name="headerFile" value="${checkstyle.header.file}" default="LICENSE.txt"/>
    <property name="fileExtensions" value="java"/>
  </module>
</module>