dev-support/checkstyle.xml

<?xml version="1.0" encoding="UTF-8"?>
<!--
  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
        "-//Puppy Crawl//DTD Check Configuration 1.3//EN"
        "http://checkstyle.sourceforge.net/dtds/configuration_1_3.dtd">
<module name="Checker">
    <module name="SuppressWithPlainTextCommentFilter">
        <property name="offCommentFormat" value='"""'/>
        <property name="onCommentFormat" value='"""'/>
    </module>

    <module name="FileTabCharacter" />
    <module name="NewlineAtEndOfFile">
        <property name="lineSeparator" value="lf" />
    </module>
    <module name="RegexpMultiline">
        <property name="format" value="\r" />
        <property name="message" value="Line contains carriage return" />
    </module>
    <module name="RegexpMultiline">
        <property name="format" value=" \n" />
        <property name="message" value="Line has trailing whitespace" />
    </module>
    <module name="RegexpMultiline">
        <property name="format" value="\n\n\n" />
        <property name="message" value="Multiple consecutive blank lines" />
    </module>
    <module name="RegexpMultiline">
        <property name="format" value="\n\n\Z" />
        <property name="message" value="Blank line before end of file" />
    </module>

    <module name="RegexpMultiline">
        <property name="format" value="\{\n\n" />
        <property name="message" value="Blank line after opening brace" />
    </module>
    <module name="RegexpMultiline">
        <property name="format" value="\n\n\s*\}" />
        <property name="message" value="Blank line before closing brace" />
    </module>
    <module name="RegexpMultiline">
        <property name="format" value="[^;]\s\)+\s*[\{;,]?\s*\n" />
        <property name="message" value="Whitespace character before closing parenthesis" />
    </module>
    <module name="RegexpMultiline">
        <property name="format" value="->\s*\{\s+\}" />
        <property name="message" value="Whitespace inside empty lambda body" />
    </module>
    <module name="RegexpMultiline">
        <property name="format" value="->(\s*+(//.*+)?\n)++\s*+\{" />
        <property name="message" value="Lambda opening brace should be on the same line as ->" />
    </module>

    <module name="RegexpSingleline">
        <property name="format" value="^import static .*\.(of|copyOf|valueOf|builder);$" />
        <property name="message" value="The following methods may not be statically imported: of, copyOf, valueOf, builder" />
    </module>
    <module name="RegexpSingleline">
        <property name="format" value="^import static (?!java\.lang\.String\.format;).*\.format;" />
        <property name="message" value="Only 'format' from java.lang.String may be statically imported" />
    </module>
    <module name="RegexpSingleline">
        <property name="format" value="^import static java\.util\.Optional\." />
        <property name="message" value="Members of Optional may not be statically imported" />
    </module>

    <module name="RegexpSingleline">
        <property name="format" value="^(?!import ).*Objects\.requireNonNull" />
        <property name="message" value="Objects.requireNonNull should only be used with static imports" />
    </module>
    <module name="RegexpSingleline">
        <property name="format" value="^(?!import ).*Math\.toIntExact" />
        <property name="message" value="Math.toIntExact should only be used with static imports" />
    </module>
    <module name="RegexpSingleline">
        <property name="format" value="^(?!import ).*ImmutableMap\.toImmutableMap" />
        <property name="message" value="ImmutableMap.toImmutableMap should only be used with static imports" />
    </module>
    <module name="RegexpSingleline">
        <property name="format" value="^(?!import ).*ImmutableList\.toImmutableList" />
        <property name="message" value="ImmutableList.toImmutableList should only be used with static imports" />
    </module>
    <module name="RegexpSingleline">
        <property name="format" value="^(?!import ).*ImmutableSet\.toImmutableSet" />
        <property name="message" value="ImmutableSet.toImmutableSet should only be used with static imports" />
    </module>
    <module name="RegexpMultiline">
        <property name="format" value="^[ \t]*import org\.testng\.Assert;$" />
        <property name="message" value="org.testng.Assert should only be used with static imports" />
    </module>
    <module name="RegexpMultiline">
        <property name="format" value="^[ \t]*import com\.google\.common\.base\.MoreObjects;$" />
        <property name="message" value="com.google.common.base.MoreObjects should only be used with static imports" />
    </module>
    <module name="RegexpMultiline">
        <property name="format" value="^[ \t]*import com\.google\.common\.base\.Preconditions;$" />
        <property name="message" value="com.google.common.base.Preconditions should only be used with static imports" />
    </module>
    <module name="RegexpMultiline">
        <property name="format" value="^[ \t]*import com\.google\.common\.base\.Verify;$" />
        <property name="message" value="com.google.common.base.Verify should only be used with static imports" />
    </module>

    <module name="SuppressWarningsFilter" />

    <module name="TreeWalker">
        <module name="SuppressWarningsHolder" />

        <module name="SuppressionXpathSingleFilter">
            <property name="checks" value="RedundantModifier"/>
            <property name="query" value="//(CLASS_DEF)/OBJBLOCK/*/MODIFIERS/*"/>
        </module>
        <module name="RedundantModifier" />

        <module name="EmptyBlock">
            <property name="option" value="text" />
            <property name="tokens" value="
                LITERAL_DO, LITERAL_ELSE, LITERAL_FINALLY, LITERAL_IF,
                LITERAL_FOR, LITERAL_TRY, LITERAL_WHILE, INSTANCE_INIT, STATIC_INIT" />
        </module>
        <module name="EmptyStatement" />
        <module name="EmptyForInitializerPad" />
        <module name="EmptyForIteratorPad">
            <property name="option" value="space" />
        </module>
        <module name="MethodParamPad">
            <property name="allowLineBreaks" value="true" />
            <property name="option" value="nospace" />
        </module>
        <module name="ParenPad" />
        <module name="TypecastParenPad" />
        <module name="NeedBraces" />
        <module name="LeftCurly">
            <property name="option" value="eol" />
            <property name="tokens" value="
                 CLASS_DEF, CTOR_DEF, INTERFACE_DEF, METHOD_DEF,
                 LITERAL_CATCH, LITERAL_DO, LITERAL_ELSE, LITERAL_FINALLY, LITERAL_FOR,
                 LITERAL_IF, LITERAL_SWITCH, LITERAL_SYNCHRONIZED, LITERAL_TRY, LITERAL_WHILE" />
        </module>
        <module name="RightCurly">
            <property name="option" value="alone" />
            <property name="tokens" value="LITERAL_ELSE" />
        </module>
        <module name="EmptyLineSeparator">
            <property name="allowNoEmptyLineBetweenFields" value="true" />
            <property name="tokens" value="
                IMPORT, STATIC_IMPORT, CLASS_DEF, INTERFACE_DEF, ENUM_DEF,
                STATIC_INIT, INSTANCE_INIT, METHOD_DEF, CTOR_DEF, VARIABLE_DEF" />
        </module>
        <module name="GenericWhitespace" />
        <module name="WhitespaceAfter" />
        <module name="NoWhitespaceAfter" />
        <module name="NoWhitespaceBefore" />
        <!-- module name="SingleSpaceSeparator" /-->
        <module name="Indentation">
            <property name="throwsIndent" value="8" />
            <property name="lineWrappingIndentation" value="8" />
        </module>

        <module name="UpperEll" />
        <module name="DefaultComesLast" />
        <module name="ArrayTypeStyle" />
        <module name="MultipleVariableDeclarations" />
        <module name="ModifierOrder" />
        <module name="OneStatementPerLine" />
        <module name="StringLiteralEquality" />
        <module name="MutableException" />
        <module name="EqualsHashCode" />
        <module name="InnerAssignment" />
        <module name="HideUtilityClassConstructor" />
        <module name="ExplicitInitialization" />
        <module name="OneTopLevelClass" />

        <module name="MemberName" />
        <module name="LocalVariableName">
            <property name="format" value="^([a-z][a-zA-Z0-9]*|_)$" />
        </module>
        <module name="LocalFinalVariableName">
            <property name="format" value="^([a-z][a-zA-Z0-9]*|_)$" />
        </module>
        <module name="TypeName" />
        <module name="PackageName">
            <property name="format" value="^[a-z][a-z0-9]*(\.[a-z][a-z0-9]*)*$" />
        </module>
        <module name="PackageDeclaration" />
        <module name="ParameterName" />
        <module name="StaticVariableName" />
        <module name="ClassTypeParameterName">
            <property name="format" value="^[A-Z][A-Za-z0-9]*$" />
        </module>
        <module name="MethodTypeParameterName">
            <property name="format" value="^[A-Z][A-Za-z0-9]*$" />
        </module>

        <module name="AnnotationUseStyle">
            <property name="trailingArrayComma" value="ignore" />
        </module>

        <module name="AvoidStarImport" />
        <module name="RedundantImport" />
        <module name="UnusedImports" />
        <module name="ImportOrder">
            <property name="groups" value="*,javax,java" />
            <property name="separated" value="true" />
            <property name="option" value="bottom" />
            <property name="sortStaticImportsAlphabetically" value="true" />
        </module>

        <module name="SuppressionXpathSingleFilter">
            <property name="checks" value="WhitespaceAround"/>
            <property name="query" value="//LITERAL_SWITCH//SLIST"/>
        </module>
        <module name="SuppressionXpathSingleFilter">
            <property name="checks" value="WhitespaceAround"/>
            <property name="query" value="//LITERAL_SWITCH//RCURLY"/>
        </module>
        <module name="WhitespaceAround">
            <property name="allowEmptyConstructors" value="true" />
            <property name="allowEmptyMethods" value="true" />
            <property name="allowEmptyLambdas" value="true" />
            <property name="allowEmptyTypes" 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_ASSERT, LITERAL_CATCH, LITERAL_DO, LITERAL_ELSE,
                LITERAL_FINALLY, LITERAL_FOR, LITERAL_IF, LITERAL_RETURN,
                LITERAL_SYNCHRONIZED, LITERAL_TRY, LITERAL_WHILE,
                LOR, LT, MINUS, MINUS_ASSIGN, MOD, MOD_ASSIGN, NOT_EQUAL,
                PLUS, PLUS_ASSIGN, QUESTION, SL, SLIST, SL_ASSIGN, SR, SR_ASSIGN,
                STAR, STAR_ASSIGN, TYPE_EXTENSION_AND" />
        </module>

        <module name="WhitespaceAfter" />

        <module name="NoWhitespaceAfter">
            <property name="tokens" value="DOT" />
            <property name="allowLineBreaks" value="false" />
        </module>

        <module name="IllegalToken">
            <property name="tokens" value="LITERAL_ASSERT" />
        </module>

        <module name="MethodName">
            <property name="format" value="^[a-z][a-zA-Z0-9_]*$"/>
        </module>

        <module name="RegexpSinglelineJava">
            <!-- Forbid "new Type[]{",  IntelliJ would reformat adding a space -->
            <!-- Forbid "new Type[]  {",  IntelliJ would reformat removing a space -->
            <property name="format" value="new\s++\w++(&lt;\?&gt;)?(\[\])++(\s{2,})?\{" />
            <property name="message" value="Incorrect whitespace before array initializer" />
            <property name="ignoreComments" value="true" />
        </module>
    </module>
</module>