checkstyle.xml

<?xml version="1.0"?>
<!--
  ~ Copyright 2013 Square Inc.
  ~
  ~ Licensed 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 1.2//EN"
    "http://www.puppycrawl.com/dtds/configuration_1_2.dtd">

<module name="Checker">
  <module name="FileTabCharacter"/>

  <!-- Forbid trailing spaces. -->
  <module name="RegexpSingleline">
    <property name="format" value="\s+$"/>
    <property name="message" value="Line has trailing spaces."/>
  </module>

  <!-- Space after 'for', 'if', 'catch', and 'switch'. -->
  <module name="RegexpSingleline">
    <property name="format" value="^\s*(for|if|switch|catch)[^ ]\("/>
    <property name="message" value="Space needed before opening parenthesis."/>
  </module>

  <!-- For each spacing. -->
  <module name="RegexpSingleline">
    <property name="format" value="^\s*for \(.*?([^ ]:|:[^ ])"/>
    <property name="message" value="Space needed around ':' character."/>
  </module>

  <!--
    - Lets us turn off a rule like this:
    - // CHECKSTYLE.OFF: LineLength blah blah blah.
    - And back on:
    - // CHECKSTYLE.ON: LineLength
    -->
  <module name="SuppressionCommentFilter">
    <property name="offCommentFormat" value="CHECKSTYLE.OFF\: ([\w\|]+)"/>
    <property name="onCommentFormat" value="CHECKSTYLE.ON\: ([\w\|]+)"/>
    <property name="checkFormat" value="$1"/>
  </module>

  <module name="TreeWalker">
    <property name="cacheFile" value="${checkstyle.cache.file}"/>

    <!-- Required by SuppressionCommentFilter. -->
    <module name="FileContentsHolder"/>

    <module name="LineLength">
      <!-- IDEA allows comments to actually go to 103 characters. -->
      <!-- http://youtrack.jetbrains.com/issue/IDEA-109737 -->
      <property name="max" value="103"/>
      <!-- Ignore imports and javadoc. -->
      <property name="ignorePattern" value="(^import|^ *\* *[^ ]+$)"/>
    </module>

    <!-- Naming conventions. -->
    <module name="LocalFinalVariableName"/>
    <module name="LocalVariableName"/>

    <!-- Coding blunders. -->
    <module name="CovariantEquals"/>
    <module name="IllegalInstantiation"/>
    <module name="RedundantThrows"/>
    <module name="SimplifyBooleanExpression"/>
    <module name="SimplifyBooleanReturn"/>

    <!-- Whitespace checks. -->
    <module name="GenericWhitespace"/>
    <module name="MethodParamPad"/>
    <module name="TypecastParenPad"/>

    <!-- Modifer checks. -->
    <module name="RedundantModifier"/>

    <!-- Import checks. -->
    <module name="AvoidStarImport"/>
    <module name="IllegalImport"/>
    <module name="RedundantImport"/>

    <!-- Misc. checks. -->
    <module name="UpperEll"/>
  </module>
</module>