checkstyle/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">
<!--
 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.
-->
<module name="Checker">
  <property name="localeLanguage" value="en"/>

  <module name="FileTabCharacter"/>

  <!-- header -->
  <module name="Header">
    <property name="headerFile" value="${headerFile}" />
  </module>

  <module name="TreeWalker">

    <!-- code cleanup -->
    <module name="UnusedImports">
      <property name="processJavadoc" value="true" />
    </module>
    <module name="RedundantImport"/>
    <module name="IllegalImport" />
    <module name="EqualsHashCode"/>
    <module name="SimplifyBooleanExpression"/>
    <module name="OneStatementPerLine"/>
    <module name="UnnecessaryParentheses" />
    <module name="SimplifyBooleanReturn"/>

    <!-- style -->
    <module name="DefaultComesLast"/>
    <module name="EmptyStatement"/>
    <module name="ArrayTypeStyle"/>
    <module name="UpperEll"/>
    <module name="LeftCurly"/>
    <module name="RightCurly"/>
    <module name="EmptyStatement"/>
    <module name="ConstantName">
      <property name="format" value="(^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$)|(^log$)"/>
    </module>
    <module name="LocalVariableName"/>
    <module name="LocalFinalVariableName"/>
    <module name="MemberName"/>
    <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="InterfaceTypeParameterName">
      <property name="format" value="^[A-Z][a-zA-Z0-9]*$$"/>
    </module>
    <module name="PackageName"/>
    <module name="ParameterName"/>
    <module name="StaticVariableName"/>
    <module name="TypeName"/>
    <module name="AvoidStarImport"/>

    <!-- variables that can be final should be final (suppressed except for Streams) -->
    <module name="FinalLocalVariable">
      <property name="tokens" value="VARIABLE_DEF,PARAMETER_DEF"/>
      <property name="validateEnhancedForLoopVariable" value="true"/>
    </module>

    <!-- dependencies -->
    <module name="ImportControl">
      <property name="file" value="${importControlFile}"/>
    </module>

    <!-- whitespace -->
    <module name="GenericWhitespace"/>
    <module name="NoWhitespaceBefore"/>
    <module name="WhitespaceAfter" />
    <module name="NoWhitespaceAfter"/>
    <module name="WhitespaceAround">
      <property name="allowEmptyConstructors" value="true"/>
      <property name="allowEmptyMethods" value="true"/>
    </module>
    <module name="Indentation"/>
    <module name="MethodParamPad"/>
    <module name="ParenPad"/>
    <module name="TypecastParenPad"/>

    <!-- locale-sensitive methods should specify locale -->
    <module name="Regexp">
      <property name="format" value="\.to(Lower|Upper)Case\(\)"/>
      <property name="illegalPattern" value="true"/>
      <property name="ignoreComments" value="true"/>
    </module>

    <module name="Regexp">
      <property name="id" value="dontUseSystemExit"/>
      <property name="format" value="System\.exit"/>
      <property name="illegalPattern" value="true"/>
      <property name="ignoreComments" value="true"/>
      <property name="message" value="'System.exit': Should not directly call System.exit, but Exit.exit instead."/>
    </module>

    <!-- code quality -->
    <module name="MethodLength"/>
    <module name="ParameterNumber">
      <!-- default is 8 -->
      <property name="max" value="13"/>
    </module>
    <module name="ClassDataAbstractionCoupling">
      <!-- default is 7 -->
      <property name="max" value="25"/>
      <property name="excludeClassesRegexps" value="AtomicInteger"/>
    </module>
    <module name="BooleanExpressionComplexity">
      <!-- default is 3 -->
      <property name="max" value="5"/>
    </module>

    <module name="ClassFanOutComplexity">
      <!-- default is 20 -->
      <property name="max" value="50"/>
    </module>
    <module name="CyclomaticComplexity">
      <!-- default is 10-->
      <property name="max" value="16"/>
    </module>
    <module name="JavaNCSS">
      <!-- default is 50 -->
      <property name="methodMaximum" value="100"/>
    </module>
    <module name="NPathComplexity">
      <!-- default is 200 -->
      <property name="max" value="500"/>
    </module>
  </module>

  <module name="SuppressionFilter">
    <property name="file" value="${suppressionsFile}"/>
  </module>
</module>