coding_style.xml

<?xml version="1.0"?>
<!--
=================================================================================================
Copyright 2011 Twitter, Inc.
_________________________________________________________________________________________________
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this work except in compliance with the License.
You may obtain a copy of the License in the LICENSE file, or 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://www.puppycrawl.com/dtds/configuration_1_3.dtd">

<!--

  Checkstyle configuration that checks the sun coding conventions from:

    - the Java Language Specification at
      http://java.sun.com/docs/books/jls/second_edition/html/index.html

    - the Sun Code Conventions at http://java.sun.com/docs/codeconv/

    - the Javadoc guidelines at
      http://java.sun.com/j2se/javadoc/writingdoccomments/index.html

    - the JDK Api documentation http://java.sun.com/j2se/docs/api/index.html

    - some best practices

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

  Most Checks are configurable, be sure to consult the documentation.

  To completely disable a check, just comment it out or delete it from the file.

  Finally, it is worth reading the documentation.
-->

<module name="Checker">
    <!--
      If you set the basedir property below, then all reported file
      names will be relative to the specified directory. See
      http://checkstyle.sourceforge.net/config.html#Checker
      <property name="basedir" value="${basedir}"/>
        -->

    <!-- TODO(John Sirois): Eliminate the strange `__shaded_by_pants__` package prefixes for
         twitter custom checks from this configuration when this issue is fixed:
           https://github.com/pantsbuild/pants/issues/1906
    -->

    <!-- We use this to turn off specific checks for specific file types.
    -->
    <module name="__shaded_by_pants__.com.twitter.common.checkstyle.SplitSuppressionFilter">
        <property name="files" value="${checkstyle.suppression.files}"/>
    </module>

    <module name="SuppressionCommentFilter">
        <property name="offCommentFormat" value="CHECKSTYLE\:OFF ([\w\|]+)"/>
        <property name="onCommentFormat" value="CHECKSTYLE\:ON ([\w\|]+)"/>
        <property name="checkFormat" value="$1"/>
    </module>

    <!-- allow suppression (via comments) of a specified check +/- 1 line from
      a in-code comment "// SUPPRESS CHECKSTYLE CheckNameHere"
      C style comments are allowed as well
    -->
    <module name="SuppressWithNearbyCommentFilter">
        <property name="influenceFormat" value="1"/>
    </module>
    <!-- now again for one line before the comment -->
    <module name="SuppressWithNearbyCommentFilter">
        <property name="influenceFormat" value="-1"/>
    </module>

    <!-- Checks whether files end with a new line.                        -->
    <!-- See http://checkstyle.sf.net/config_misc.html#NewlineAtEndOfFile -->
    <module name="NewlineAtEndOfFile"/>

    <!-- Checks that property files contain the same keys.         -->
    <!-- See http://checkstyle.sf.net/config_misc.html#Translation -->
    <module name="Translation"/>

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

    <!-- Miscellaneous other checks.                   -->
    <!-- See http://checkstyle.sf.net/config_misc.html -->
    <module name="RegexpSingleline">
        <property name="format" value="\s+$"/>
        <property name="minimum" value="0"/>
        <property name="maximum" value="0"/>
        <property name="message" value="Line has trailing spaces."/>
    </module>

    <module name="TreeWalker">
        <property name="tabWidth" value="2"/>

        <!-- needed for SuppressWithNearbyCommentFilter -->
        <module name="FileContentsHolder"/>

        <!-- Annotations -->
        <module name="AnnotationUseStyle"/>
        <module name="MissingDeprecated"/>
        <module name="MissingOverride"/>
        <module name="PackageAnnotation"/>

        <!-- Checks for Javadoc comments.                     -->
        <!-- See http://checkstyle.sf.net/config_javadoc.html -->
        <module name="__shaded_by_pants__.com.twitter.common.checkstyle.JavadocMethodRegexCheck">
            <!-- don't require javadoc for methods shorter than or equal to
            this many lines (including opening & closing brace lines)
            -->
            <property name="minLineCount" value="5"/>
            <!-- javadoc doesn't need one @param, @return, @throws tags -->
            <property name="scope" value="public"/>
            <property name="allowMissingParamTags" value="true"/>
            <property name="allowMissingThrowsTags" value="true"/>
            <property name="allowMissingReturnTag" value="true"/>
            <!-- simple set/get methods don't need javadoc comments -->
            <property name="allowMissingPropertyJavadoc" value="true" />
            <!-- Allow tags for runtime exceptions that are not explicitly declared -->
            <property name="allowUndeclaredRTE" value="true" />
        </module>
        <module name="JavadocType">
            <property name="excludeScope" value="private"/>
        </module>
        <module name="JavadocStyle">
            <property name="checkFirstSentence" value="false"/>
            <property name="checkEmptyJavadoc" value="true"/>
        </module>

        <!-- Checks for Naming Conventions.                  -->
        <module name="ClassTypeParameterName">
            <property name="format" value="^[A-Z][A-Z0-9]?$"/>
        </module>
        <module name="MethodTypeParameterName">
            <property name="format" value="^[A-Z][A-Z0-9]?$"/>
        </module>
        <module name="ConstantName"/>
        <module name="LocalFinalVariableName">
            <!-- allow VAR_NAME and varName in local final variables,
            leave it up to user to use them appropriately depending on whether
            or not the variable is A_CONSTANT_VARIBLE, or aMutableVariable.
            -->
            <property name="format" value="^(([a-z][a-zA-Z0-9]*)|([A-Z][A-Z0-9]*(_[A-Z0-9]+)*))$" />

        </module>
        <module name="LocalVariableName"/>
        <module name="MemberName"/>
        <module name="__shaded_by_pants__.com.twitter.common.checkstyle.NonOverriddenMethodName">
            <property name="format" value="^(([a-z][a-zA-Z0-9]*)|(\$tag))$" />
        </module>
        <module name="PackageName"/>
        <module name="ParameterName"/>
        <module name="StaticVariableName"/>
        <module name="TypeName"/>

        <!-- Following interprets the header file as regular expressions. -->
        <!-- <module name="RegexpHeader"/>                                -->

        <!-- Checks for imports                              -->
        <!-- See http://checkstyle.sf.net/config_import.html -->
        <module name="AvoidStarImport">
            <property name="excludes" value="org.junit.Assert"/>
            <property name="excludes" value="java.util.*"/>
        </module>
        <module name="IllegalImport"/> <!-- defaults to sun.* packages -->
        <module name="RedundantImport"/>
        <module name="UnusedImports"/>
        <module name="ImportOrder">
            <property name="groups"
                      value="/^javax?\./,scala,com,net,org,com.twitter"/>
            <property name="ordered" value="true"/>
            <property name="separated" value="true"/>
            <property name="option" value="bottom"/>
            <message key="import.ordering"
                     value="Wrong order for ''{0}'' import. Order should be: java, javax, scala, com, net, org,
com.twitter. Each group should be separated by a single blank line." />
        </module>

        <!-- Checks for Size Violations.                    -->
        <!-- See http://checkstyle.sf.net/config_sizes.html -->
        <module name="LineLength">
            <property name="max" value="100"/>
            <!-- Ignore import statements and javadoc comments                 -->
            <property name="ignorePattern" value="^import.*$|^ *\*( |[^/]) *.*$"/>
        </module>
        <module name="OuterTypeNumber"/>

        <!-- Checks for whitespace                               -->
        <!-- See http://checkstyle.sf.net/config_whitespace.html -->
        <module name="EmptyForInitializerPad"/>
        <module name="EmptyForIteratorPad"/>
        <module name="GenericWhitespace"/>
        <module name="MethodParamPad"/>
        <module name="NoWhitespaceAfter"/>
        <module name="NoWhitespaceBefore"/>
        <module name="OperatorWrap"/>
        <module name="ParenPad"/>
        <module name="TypecastParenPad"/>
        <module name="WhitespaceAfter"/>
        <module name="WhitespaceAround">
            <!-- Intentionally excludes RCURLY (default) since it trips on anonymous
                 inner class declarations when chained with a method call.
            -->
            <property name="tokens" value="ASSIGN,BAND,BAND_ASSIGN,BOR,BOR_ASSIGN,BSR,BSR_ASSIGN,
                                       BXOR,BXOR_ASSIGN,COLON,DIV,DIV_ASSIGN,EQUAL,GE,GT,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>

        <!-- Modifier Checks                                    -->
        <!-- See http://checkstyle.sf.net/config_modifiers.html -->
        <module name="ModifierOrder"/>
        <module name="RedundantModifier"/>

        <!-- Checks for blocks. You know, those {}'s         -->
        <!-- See http://checkstyle.sf.net/config_blocks.html -->
        <module name="AvoidNestedBlocks"/>
        <module name="EmptyBlock">
            <!-- Allow comments to satisfy the EmptyBlock check -->
            <property name="option" value="text"/>
        </module>
        <module name="LeftCurly"/>
        <module name="NeedBraces"/>
        <module name="RightCurly"/>

        <!-- Checks for common coding problems               -->
        <!-- See http://checkstyle.sf.net/config_coding.html -->
        <module name="CovariantEquals"/>
        <module name="EmptyStatement"/>
        <module name="EqualsAvoidNull"/>
        <module name="EqualsHashCode"/>
        <module name="HiddenField">
            <property name="ignoreConstructorParameter" value="true"/>
            <property name="ignoreSetter" value="true"/>
        </module>
        <!-- Checks for catch of overly general exception classes like
             RuntimeException, Exception, Throwable, etc. -->
        <module name="IllegalCatch"/>
        <!-- disallow calling constructors on these classes
             calling factories is the only way to create these objects
        -->
        <module name="IllegalInstantiation">
            <property name="classes" value="java.lang.Boolean"/>
        </module>
        <module name="IllegalToken">
            <property name="tokens" value="LITERAL_NATIVE"/>
        </module>
        <!-- TODO(John Sirois): Modify this rule to pass on enhanced try statements
             in java7 like it does for for loops -->
        <!-- <module name="InnerAssignment"/> -->
        <module name="MissingSwitchDefault"/>
        <module name="ModifiedControlVariable"/>
        <module name="RedundantThrows">
            <property name="allowUnchecked" value="true"/>
            <!-- Need to set to true, else we get lots of errors:
                 "Unable to get class information for ThriftException -->
            <property name="suppressLoadErrors" value="true"/>
            <message key="redundant.throws.duplicate"
                     value="Redundant throws: {0} listed more than one time. This
will trigger spuriously if checkstyle can''t resolve {0} on its classpath." />
            <message key="redundant.throws.subclass"
                     value="Redundant throws: {0} is a subclass of {1}. This
will trigger spuriously if checkstyle can''t resolve either class on its
classpath." />
        </module>

        <module name="SimplifyBooleanExpression"/>
        <module name="SimplifyBooleanReturn"/>
        <module name="StringLiteralEquality"/>
        <module name="NestedForDepth">
            <property name="max" value="2"/>
        </module>
        <module name="NestedTryDepth">
            <property name="max" value="1"/>
        </module>
        <module name="NoClone"/>
        <module name="NoFinalizer"/>
        <module name="SuperClone"/>
        <module name="SuperFinalize"/>
        <!-- disallow throws Throwable unless a superclass or interface requires this -->
        <module name="__shaded_by_pants__.com.twitter.common.checkstyle.IllegalThrowsCheck"/>
        <module name="PackageDeclaration">
            <property name="ignoreDirectoryName" value="true"/>
        </module>
        <module name="JUnitTestCase"/>
        <module name="ParameterAssignment"/>
        <module name="DefaultComesLast"/>
        <module name="FallThrough"/>
        <module name="MultipleVariableDeclarations"/>
        <module name="UnnecessaryParentheses"/>
        <module name="OneStatementPerLine"/>

        <module name="FinalClass"/>
        <module name="HideUtilityClassConstructor"/>
        <module name="InterfaceIsType"/>
        <module name="VisibilityModifier">
            <property name="protectedAllowed" value="true"/>
            <!-- Allow public members at the coder's discretion, for struct-like things. -->
            <property name="publicMemberPattern" value="^.*$" />
        </module>
        <module name="MutableException"/>

        <!-- Miscellaneous other checks.                   -->
        <!-- See http://checkstyle.sf.net/config_misc.html -->
        <module name="ArrayTypeStyle"/>
        <module name="UpperEll"/>
        <module name="ArrayTypeStyle"/>
        <module name="OuterTypeFilename"/>

        <!-- Regexp checks -->
        <module name="RegexpSinglelineJava">
            <property name="format" value="System.exit"/>
            <property name="ignoreComments" value="true"/>
            <property name="message"
                      value="Don't System.exit(), throw a RuntimeException()" />
        </module>
    </module>
</module>