checkstyle.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE module PUBLIC "-//Puppy Crawl//DTD Check Configuration 1.3//EN"
        "http://www.puppycrawl.com/dtds/configuration_1_3.dtd">
<!-- This is a checkstyle configuration file. For descriptions of
what the following rules do, please see the checkstyle configuration
page at http://checkstyle.sourceforge.net/config.html -->
<module name="Checker">

    <!-- no tabs -->
    <module name="FileTabCharacter"/>

    <module name="StrictDuplicateCode">
        <property name="min" value="30"/>
    </module>

    <module name="SuppressWarningsFilter"/>

    <!-- All Java AST specific tests live under TreeWalker module. -->
    <module name="TreeWalker">

        <module name="SuppressWarningsHolder"/>

        <module name="CyclomaticComplexity">
            <property name="max" value="10"/>
        </module>

        <module name="ArrayTrailingComma"/>

        <module name="CovariantEquals"/>

        <module name="EqualsAvoidNull"/>

        <!-- think about doing this everywhere
        <module name="FinalLocalVariable">
           <property name="tokens" value="VARIABLE_DEF,PARAMETER_DEF"/>
        </module>

        <module name="MagicNumber"/>
        -->

        <module name="MissingSwitchDefault"/>

        <module name="StringLiteralEquality"/>

        <!-- <module name="RedundantThrows"/> -->

        <module name="RedundantImport">
            <!-- Checks for redundant import statements. -->
            <property name="severity" value="error"/>
        </module>

        <!-- See http://checkstyle.sf.net/config_javadoc.html -->
        <module name="JavadocMethod">
            <property name="scope" value="protected"/>
            <property name="severity" value="error"/>
            <property name="allowMissingParamTags" value="true"/>
            <property name="allowMissingThrowsTags" value="true"/>
            <property name="allowThrowsTagsForSubclasses" value="true"/>
            <property name="allowUndeclaredRTE" value="true"/>
        </module>

        <!-- See http://checkstyle.sf.net/config_javadoc.html -->
        <module name="JavadocVariable">
            <property name="scope" value="protected"/>
            <property name="severity" value="error"/>
        </module>

        <!-- See http://checkstyle.sf.net/config_javadoc.html -->
        <module name="JavadocType">
            <property name="scope" value="private"/>
            <property name="severity" value="error"/>
        </module>

        <!-- See http://checkstyle.sf.net/config_javadoc.html -->
        <module name="JavadocStyle">
            <property name="checkFirstSentence" value="false"/>
            <property name="severity" value="error"/>
        </module>

        <!-- NAMING CHECKS -->

        <module name="PackageName">
            <property name="format" value="^[a-z]+(\.[a-z][a-z0-9]{1,})*$"/>
            <property name="severity" value="warning"/>
        </module>

        <module name="TypeNameCheck">
            <!-- Validates static, final fields against the
            expression "^[A-Z][a-zA-Z0-9]*$". -->
            <metadata name="altname" value="TypeName"/>
            <property name="severity" value="warning"/>
        </module>

        <module name="ConstantNameCheck">
            <!-- Validates non-private, static, final fields against the supplied
            public/package final fields "^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$". -->
            <metadata name="altname" value="ConstantName"/>
            <property name="applyToPublic" value="true"/>
            <property name="applyToProtected" value="true"/>
            <property name="applyToPackage" value="true"/>
            <property name="applyToPrivate" value="true"/>
            <property name="format" value="^([A-Z][A-Z0-9]*(_[A-Z0-9]+)*|FLAG_.*)$"/>
            <message key="name.invalidPattern"
                     value="Variable ''{0}'' should be in ALL_CAPS (if it is a constant) or be private (otherwise)."/>
            <property name="severity" value="warning"/>
        </module>

        <module name="StaticVariableNameCheck">
            <!-- Validates static, non-final fields against the supplied
            expression "^[a-z][a-zA-Z0-9]*_?$". -->
            <metadata name="altname" value="StaticVariableName"/>
            <property name="applyToPublic" value="true"/>
            <property name="applyToProtected" value="true"/>
            <property name="applyToPackage" value="true"/>
            <property name="applyToPrivate" value="true"/>
            <property name="format" value="^[a-z][a-zA-Z0-9]*_?$"/>
            <property name="severity" value="warning"/>
        </module>

        <module name="MemberNameCheck">
            <!-- Validates non-static members against the supplied expression. -->
            <metadata name="altname" value="MemberName"/>
            <property name="applyToPublic" value="true"/>
            <property name="applyToProtected" value="true"/>
            <property name="applyToPackage" value="true"/>
            <property name="applyToPrivate" value="true"/>
            <property name="format" value="^[a-z][a-zA-Z0-9]*$"/>
            <property name="severity" value="warning"/>
        </module>

        <module name="MethodNameCheck">
            <!-- Validates identifiers for method names. -->
            <metadata name="altname" value="MethodName"/>
            <property name="format" value="^[a-z][a-zA-Z0-9]*(_[a-zA-Z0-9]+)*$"/>
            <property name="severity" value="warning"/>
        </module>

        <module name="ParameterName">
            <!-- Validates identifiers for method parameters against the
              expression "^[a-z][a-zA-Z0-9]*$". -->
            <property name="severity" value="warning"/>
        </module>

        <module name="LocalFinalVariableName">
            <!-- Validates identifiers for local final variables against the
              expression "^[a-z][a-zA-Z0-9]*$". -->
            <property name="severity" value="warning"/>
        </module>

        <module name="LocalVariableName">
            <!-- Validates identifiers for local variables against the
              expression "^[a-z][a-zA-Z0-9]*$". -->
            <property name="severity" value="warning"/>
        </module>


        <!-- LENGTH and CODING CHECKS -->

        <module name="LineLength">
            <!-- Checks if a line is too long. -->
            <property name="max" value="${com.puppycrawl.tools.checkstyle.checks.sizes.LineLength.max}" default="140"/>
            <property name="severity" value="error"/>

            <!--
              The default ignore pattern exempts the following elements:
                - import statements
                - long URLs inside comments
            -->

            <property name="ignorePattern"
                      value="${com.puppycrawl.tools.checkstyle.checks.sizes.LineLength.ignorePattern}"
                      default="^(package .*;\s*)|(import .*;\s*)|( *\* *https?://.*)$"/>
        </module>

        <module name="LeftCurly">
            <!-- Checks for placement of the left curly brace ('{'). -->
            <property name="severity" value="warning"/>
        </module>

        <module name="RightCurly">
            <!-- Checks right curlies on CATCH, ELSE, and TRY blocks are on
            the same line. e.g., the following example is fine:
            <pre>
              if {
                ...
              } else
            </pre>
            -->
            <!-- This next example is not fine:
            <pre>
              if {
                ...
              }
              else
            </pre>
            -->
            <property name="option" value="same"/>
            <property name="severity" value="warning"/>
        </module>

        <!-- Checks for braces around if and else blocks -->
        <module name="NeedBraces">
            <property name="severity" value="warning"/>
            <property name="tokens" value="LITERAL_IF, LITERAL_ELSE, LITERAL_FOR, LITERAL_WHILE, LITERAL_DO"/>
        </module>

        <module name="UpperEll">
            <!-- Checks that long constants are defined with an upper ell.-->
            <property name="severity" value="error"/>
        </module>

        <module name="FallThrough">
            <!-- Warn about falling through to the next case statement.  Similar to
            javac -Xlint:fallthrough, but the check is suppressed if a single-line comment
            on the last non-blank line preceding the fallen-into case contains 'fall through' (or
            some other variants which we don't publicized to promote consistency).
            -->
            <property name="reliefPattern"
                      value="fall through|Fall through|fallthru|Fallthru|falls through|Falls through|fallthrough|Fallthrough|No break|NO break|no break|continue on"/>
            <property name="severity" value="error"/>
        </module>


        <!-- MODIFIERS CHECKS -->

        <module name="ModifierOrder">
            <!-- Warn if modifier order is inconsistent with JLS3 8.1.1, 8.3.1, and
                 8.4.3.  The prescribed order is:
                 public, protected, private, abstract, static, final, transient, volatile,
                 synchronized, native, strictfp
              -->
        </module>


        <!-- WHITESPACE CHECKS -->

        <module name="WhitespaceAround">
            <!-- Checks that various tokens are surrounded by whitespace.
                 This includes most binary operators and keywords followed
                 by regular or curly braces.
            -->
            <property name="tokens"
                      value="ASSIGN, BAND, BAND_ASSIGN, BOR, BOR_ASSIGN, BSR, BSR_ASSIGN, BXOR, BXOR_ASSIGN, COLON, DIV_ASSIGN, EQUAL, GE, GT, LAND, LE, LITERAL_CATCH, LITERAL_DO, LITERAL_ELSE, LITERAL_FINALLY, LITERAL_FOR, LITERAL_IF, LITERAL_RETURN, LITERAL_SYNCHRONIZED, LITERAL_TRY, LITERAL_WHILE, LOR, LT, MINUS_ASSIGN, MOD_ASSIGN, NOT_EQUAL, PLUS_ASSIGN, QUESTION, SL, SL_ASSIGN, SR_ASSIGN, STAR_ASSIGN"/>
            <property name="severity" value="error"/>
        </module>

        <module name="WhitespaceAfter">
            <!-- Checks that commas, semicolons and typecasts are followed by
                 whitespace.
            -->
            <property name="tokens" value="COMMA, SEMI"/>
        </module>

        <module name="NoWhitespaceAfter">
            <!-- Checks that there is no whitespace after various unary operators.
                 Linebreaks are allowed.
            -->
            <property name="tokens" value="BNOT, DEC, DOT, INC, LNOT, UNARY_MINUS,         UNARY_PLUS"/>
            <property name="allowLineBreaks" value="true"/>
            <property name="severity" value="error"/>
        </module>

        <module name="NoWhitespaceBefore">
            <!-- Checks that there is no whitespace before various unary operators.
                 Linebreaks are allowed.
            -->
            <property name="tokens" value="SEMI, DOT, POST_DEC, POST_INC"/>
            <property name="allowLineBreaks" value="true"/>
            <property name="severity" value="error"/>
        </module>

        <module name="ParenPad">
            <!-- Checks that there is no whitespace before close parens or after
                 open parens.
            -->
            <property name="severity" value="warning"/>
        </module>
    </module>
</module>