checkstyle.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE module PUBLIC "-//Checkstyle//DTD Check Configuration 1.3//EN" "https://checkstyle.org/dtds/configuration_1_3.dtd">

<!--
    Checkstyle-Configuration: JMRI
    Description: Checkstyle configuration for JMRI
-->
<module name="Checker">
  <!-- default severity is warning to not fail in CI -->
  <!-- individual checks that should fail in CI have error severity -->
  <property name="severity" value="warning"/>
  <module name="SuppressWarningsFilter"/>
  <module name="BeforeExecutionExclusionFileFilter">
    <!-- do not check images -->
    <property name="fileNamePattern" value=".*(gif|png)$"/>
  </module>
  <module name="TreeWalker">
    <module name="SuppressWarningsHolder"/>
    <module name="RedundantImport">
      <property name="severity" value="error"/>
    </module>
    <module name="UnusedImports"/>
    <module name="PackageDeclaration">
      <property name="severity" value="error"/>
    </module>
    <module name="UpperEll">
      <property name="severity" value="error"/>
    </module>
    <module name="InterfaceIsType"/>
    <module name="MissingOverride">
      <property name="severity" value="error"/>
    </module>
    <module name="Regexp">
      <!-- Flag uses of FindBugs NonNull that need to be javax.annotations.Nonnull -->
      <property name="format" value="edu\.umd\.cs\.findbugs\.annotations\.NonNull"/>
      <property name="illegalPattern" value="true"/>
      <property name="severity" value="error"/>
      <!-- message is appended to "Line matches the illegal pattern " -->
      <property name="message" value="edu.umd.cs.findbugs.annotations.NonNull (replace with javax.annotations.Nonnull)" />
    </module>
    <module name="Regexp">
      <!-- Flag uses of e.g. {0} in a logging statement (should be {} )  -->
      <!-- the attribute takes the regex string, without Java quoting, then uses the Java regex support -->
      <property name="format" value="log\..*\(.*\{[0-9][0-9]*}"/>
      <property name="illegalPattern" value="true"/>
      <property name="severity" value="error"/>
      <!-- message is appended to "Line matches the illegal pattern " -->
      <property name="message" value="{digit} in logging call, should be {}" />
    </module>
  </module>
  <module name="FileTabCharacter">
    <property name="severity" value="error"/>
    <property name="eachLine" value="true"/>
    <property name="fileExtensions" value="java"/>
  </module>
  <module name="NewlineAtEndOfFile">
    <property name="severity" value="error"/>
    <property name="lineSeparator" value="lf"/>
    <property name="fileExtensions" value="java, xml, py"/>
  </module>
  <!-- disable newline at end of file check for JHelpDev generated content -->
  <module name="SuppressionSingleFilter">
    <property name="checks" value="NewlineAtEndOfFile"/>
    <property name="files" value="help\/(en|fr)/JmriHelp_(en|fr)(Index|TOC)\.xml$"/>
  </module>
  <!-- from https://stackoverflow.com/questions/32903412/how-to-tell-checkstyle-to-check-all-lines-for-linefeed-newline-lf-and-not-crlf/33000451 -->
  <module name="RegexpMultiline">
    <property name="format" value="\r\n"/>
    <property name="message" value="CRLF line endings are prohibited"/>
  </module> 
  <!-- disable warnings for existing interfaces that are not types -->
  <!-- serves as example of suppressing a check against a Regex of files -->
  <module name="SuppressionSingleFilter">
    <property name="checks" value="InterfaceIsType"/>
    <property name="files" value="(\/ussctc\/|\/rps\/)Constants.java$"/>
  </module>
  <!-- disable package name check on sample package-info.java -->
  <module name="SuppressionSingleFilter">
    <property name="checks" value="PackageDeclaration"/>
    <property name="files" value="java\/package-info.java$"/>
  </module>
</module>