style/checkstyle.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE module PUBLIC
        "-//Checkstyle//DTD Checkstyle Configuration 1.3//EN"
        "https://checkstyle.org/dtds/configuration_1_3.dtd">
<module name="Checker">
    <property name="charset" value="UTF-8"/>
    <property name="severity" value="info"/>
    <property name="fileExtensions" value="java, properties, xml"/>

    <module name="FileTabCharacter">
        <property name="eachLine" value="true"/>
    </module>
    <module name="LineLength">
        <property name="max" value="100"/>
        <property name="ignorePattern" value="^package.*|^import.*|a href|href|http://|https://|ftp://|Reflection\.*"/>
    </module>
    <module name="RegexpSingleline">
        <property name="format" value="System\.out\.println"/>
        <property name="message" value="Prohibit invoking System.out.println in source code !"/>
    </module>

    <module name="TreeWalker">
        <module name="PackageName">
            <property name="format" value="^[a-z]+(\.[a-z][a-z0-9]*)*$"/>
            <message key="name.invalidPattern"  value="Package name ''{0}'' must match pattern ''{1}''."/>
        </module>
        <!--        <module name="ImportOrder">-->
        <!--            <property name="staticGroups"-->
        <!--                      value="org.apache,java,javax,org,com,com.baidu.hugegraph"/>-->
        <!--            <property name="separatedStaticGroups" value="true"/>-->
        <!--            <property name="groups" value="org.apache,java,javax,org,com,com.baidu.hugegraph"/>-->
        <!--            <property name="ordered" value="true"/>-->
        <!--            <property name="separated" value="true"/>-->
        <!--            <property name="option" value="top"/>-->
        <!--            <property name="sortStaticImportsAlphabetically" value="true"/>-->
        <!--        </module>-->
        <module name="AvoidStarImport"/>
        <module name="RedundantImport"/>
        <module name="RedundantModifier"/>
        <module name="UnusedImports"/>
        <module name="EmptyLineSeparator">
            <property name="allowMultipleEmptyLines" value="false"/>
            <property name="allowMultipleEmptyLinesInsideClassMembers" value="false"/>
            <property name="tokens" value="PACKAGE_DEF, IMPORT, STATIC_IMPORT, CLASS_DEF,INTERFACE_DEF, ENUM_DEF, STATIC_INIT, INSTANCE_INIT, METHOD_DEF,CTOR_DEF"/>
        </module>
        <module name="ModifierOrder"/>
        <module name="TypeName">
            <message key="name.invalidPattern" value="Type name ''{0}'' must match pattern ''{1}''."/>
        </module>
        <module name="ClassTypeParameterName">
            <property name="format" value="^[A-Z][a-zA-Z0-9]*$"/>
            <message key="name.invalidPattern" value="Class type name ''{0}'' must match pattern ''{1}''."/>
        </module>
        <module name="ConstantName">
            <property name="format" value="^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$"/>
        </module>
        <module name="LocalVariableName">
            <property name="tokens" value="VARIABLE_DEF"/>
            <property name="format" value="^[a-z]([a-zA-Z0-9]*)?$"/>
            <message key="name.invalidPattern"
                     value="Local variable name ''{0}'' must match pattern ''{1}''."/>
        </module>
        <module name="MemberName">
            <property name="format" value="^[a-z][a-zA-Z0-9]*$"/>
            <message key="name.invalidPattern"
                     value="Member name ''{0}'' must match pattern ''{1}''."/>
        </module>
        <module name="ParameterName">
            <property name="format" value="^[a-z]([a-zA-Z0-9]*)?$"/>
            <message key="name.invalidPattern"
                     value="Parameter name ''{0}'' must match pattern ''{1}''."/>
        </module>
        <module name="CatchParameterName">
            <property name="format" value="^[a-z]([a-zA-Z0-9]*)?$"/>
            <message key="name.invalidPattern"
                     value="Catch parameter name ''{0}'' must match pattern ''{1}''."/>
        </module>
        <module name="ArrayTypeStyle"/>
        <module name="MethodTypeParameterName">
            <property name="format" value="^[A-Z][a-zA-Z0-9]*$"/>
            <message key="name.invalidPattern"
                     value="Method type name ''{0}'' must match pattern ''{1}''."/>
        </module>
        <module name="MethodName">
            <property name="format" value="^[a-z][a-z0-9][a-zA-Z0-9_]*$"/>
            <message key="name.invalidPattern"
                     value="Method name ''{0}'' must match pattern ''{1}''."/>
        </module>
        <module name="InterfaceTypeParameterName">
            <property name="format" value="^[A-Z][a-zA-Z0-9]*$"/>
            <message key="name.invalidPattern"
                     value="Interface type name ''{0}'' must match pattern ''{1}''."/>
        </module>
        <module name="EqualsHashCode"/>
        <module name="MissingSwitchDefault"/>
        <module name="DefaultComesLast"/>
        <module name="SuperClone"/>
        <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="2"/>
            <property name="lineWrappingIndentation" value="4"/>
            <property name="arrayInitIndent" value="4"/>
        </module>
        <module name="UpperEll"/>
        <module name="IllegalImport">
            <property name="regexp" value="true"/>
            <property name="illegalPkgs"
                      value="^com\.google\.api\.client\.repackaged,
                      ^avro\.shaded, ^org\.apache\.hadoop\.hbase\.shaded,
                      ^org\.apache\.hadoop\.shaded,
                      ^javax\.ws\.rs\.ext,
                      ^cc\.concurrent\.mango\.util\.concurrent,
                      ^org\.apache\.curator-test\.shaded,
                      ^com\.sun\.istack,
                      ^org\.jetbrains\.annotations,
                      ^jline\.internal,
                      ^com\.cronutils\.utils,
                      ^javax\.ws\.rs\.ext,
                      ^org\.jboss\.netty\.util\.internal,
                      ^com\.sun\.javafx,
                      ^io\.reactivex\.annotations,
                      ^org\.codehaus\.jackson"/>
            <property name="illegalClasses"
                      value="^java\.util\.logging\.Logging,
                      ^sun\.misc\.BASE64Encoder,
                      ^sun\.misc\.BASE64Decoder,
                      ^jdk\.internal\.jline\.internal\.Nullable"/>
        </module>
        <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="ParenPad"/>
        <module name="OperatorWrap">
            <property name="option" value="eol"/>
            <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="allowSamelineMultipleAnnotations" value="false"/>
            <property name="allowSamelineSingleParameterlessAnnotation"
                      value="false"/>
            <property name="allowSamelineParameterizedAnnotation" value="true"/>
            <property name="tokens" value="METHOD_DEF, CTOR_DEF"/>
        </module>
        <module name="EmptyCatchBlock">
            <property name="exceptionVariableName" value="expected"/>
        </module>
        <module name="CommentsIndentation"/>
        <module name="NoLineWrap">
            <!--            <property name="severity" value="error"/>-->
        </module>
        <module name="EmptyStatement">
            <!--            <property name="severity" value="error"/>-->
        </module>
        <module name="NeedBraces">
            <!--            <property name="severity" value="error"/>-->
        </module>
        <module name="LeftCurly">
            <!--            <property name="severity" value="error"/>-->
        </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="AvoidNestedBlocks">
            <property name="allowInSwitchCase" 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="AvoidEscapedUnicodeCharacters">
            <property name="allowEscapesForControlCharacters" value="true"/>
            <property name="allowByTailComment" value="true"/>
            <property name="allowNonPrintableEscapes" value="true"/>
        </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="OneStatementPerLine"/>
        <module name="MultipleVariableDeclarations"/>
        <module name="MissingSwitchDefault"/>
        <module name="FallThrough"/>
        <module name="OuterTypeFilename">
            <!--            <property name="severity" value="error"/>-->
        </module>
        <module name="OneTopLevelClass">
            <!--            <property name="severity" value="error"/>-->
        </module>
        <module name="JavadocStyle">
            <property name="endOfSentenceFormat" value=""/>
        </module>
        <module name="JavadocType">
            <property name="scope" value="protected"/>
            <property name="allowMissingParamTags" value="true"/>
        </module>
    </module>
</module>