checkstyle.xml

<?xml version="1.0"?>
<!--
  ~ OpenGr8on, open source extensions to systems based on Grenton devices
  ~ Copyright (C) 2023 Piotr Sobiech
  ~
  ~ This program is free software: you can redistribute it and/or modify
  ~ it under the terms of the GNU Affero General Public License as
  ~ published by the Free Software Foundation, either version 3 of the
  ~ License, or (at your option) any later version.
  ~
  ~ This program is distributed in the hope that it will be useful,
  ~ but WITHOUT ANY WARRANTY; without even the implied warranty of
  ~ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  ~ GNU Affero General Public License for more details.
  ~
  ~ You should have received a copy of the GNU Affero General Public License
  ~ along with this program.  If not, see <https://www.gnu.org/licenses/>.
  -->

<!DOCTYPE module PUBLIC
  "-//Checkstyle//DTD Checkstyle Configuration 1.3//EN"
  "https://checkstyle.org/dtds/configuration_1_3.dtd">
<module name="Checker">
  <property name="severity" value="error"/>

  <property name="fileExtensions" value="java, properties, xml"/>

  <!-- Excludes all 'module-info.java' files              -->
  <!-- See https://checkstyle.org/config_filefilters.html -->
  <module name="BeforeExecutionExclusionFileFilter">
    <property name="fileNamePattern" value="module\-info\.java$"/>
  </module>

  <!-- https://checkstyle.org/config_filters.html#SuppressionFilter -->
  <module name="SuppressionFilter">
    <property name="file" value="checkstyle-suppressions.xml"/>
    <property name="optional" value="true"/>
  </module>

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

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

  <!-- Checks for Size Violations.                    -->
  <!-- See https://checkstyle.org/config_sizes.html -->
  <module name="FileLength"/>
  <module name="LineLength">
    <property name="fileExtensions" value="java"/>
    <property name="max" value="200"/>
  </module>

  <!-- Checks for whitespace                               -->
  <!-- See https://checkstyle.org/config_whitespace.html -->
  <module name="FileTabCharacter"/>

  <!-- Miscellaneous other checks.                   -->
  <!-- See https://checkstyle.org/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>

  <!-- Enforces blank lines after block-closing curly braces (with exceptions). -->
  <module name="RegexpMultiline">
    <property name="format" value="}\n(?![ \t]*(else|case|catch|finally|[})]|\*)|$)"/>
    <property name="message" value="Missing newline after code block"/>
  </module>

  <module name="RegexpMultiline">
    <property name="format" value="(this|super)\([^\)]*\);\n(?!\n|([ \t]*}))"/>
    <property name="message" value="Missing newline after this/super"/>
  </module>

  <module name="RegexpMultiline">
    <property name="format" value=";\n[ \t]*(?!\n[ \t]*)(return )"/>
    <property name="message" value="Missing newline before return"/>
  </module>

  <module name="RegexpMultiline">
    <property name="format" value="System\.(out)|(err)\.print(ln)?\("/>
    <property name="message" value="Printing directly to console"/>
  </module>

  <module name="RegexpSingleline">
    <property name="format" value="[ \t]+\)\.[^\(]+\("/>
    <property name="message" value="Incorrect method chaining"/>
  </module>

  <module name="RegexpSingleline">
    <property name="format" value="\.stream\(\)\.(?![^;]*;$)(?![^\{]*\{$)"/>
    <property name="message" value="Incorrect stream() placement"/>
  </module>

  <module name="SuppressWarningsFilter"/>
  <module name="TreeWalker">
    <module name="SuppressWarningsHolder"/>

    <!-- Checks for Javadoc comments.                     -->
    <!-- See https://checkstyle.org/config_javadoc.html -->
    <module name="InvalidJavadocPosition"/>

    <!-- Checks for Naming Conventions.                  -->
    <!-- See https://checkstyle.org/config_naming.html -->
    <module name="ConstantName">
      <property name="format" value="^([A-Z][A-Z0-9]*(_[A-Z0-9]+)*)$"/>
    </module>
    <module name="LocalFinalVariableName"/>
    <module name="LocalVariableName"/>
    <module name="MemberName">
      <property name="format" value="^LOGGER|([a-z][a-zA-Z0-9]*)$"/>
    </module>
    <module name="MethodName">
      <property name="format" value="^_?([a-z][a-zA-Z0-9]*)$"/>
    </module>
    <module name="PackageName"/>
    <module name="ParameterName"/>
    <module name="StaticVariableName"/>
    <module name="TypeName"/>

    <!-- Checks for imports                              -->
    <!-- See https://checkstyle.org/config_imports.html -->
    <module name="AvoidStarImport"/>
    <module name="IllegalImport"/> <!-- defaults to sun.* packages -->
    <module name="IllegalImport">
      <property name="illegalPkgs" value="com.google.inject.Inject,com.google.inject.Singleton"/>
    </module>
    <module name="RedundantImport"/>
    <module name="UnusedImports">
      <property name="processJavadoc" value="false"/>
    </module>

    <!-- Checks for Size Violations.                    -->
    <!-- See https://checkstyle.org/config_sizes.html -->
    <module name="MethodLength"/>
    <module name="ParameterNumber">
      <property name="max" value="7"/>
      <property name="tokens" value="METHOD_DEF"/>
    </module>
    <module name="ParameterNumber">
      <property name="max" value="10"/>
      <property name="tokens" value="CTOR_DEF"/>
    </module>

    <!-- Checks for whitespace                               -->
    <!-- See https://checkstyle.org/config_whitespace.html -->
    <module name="EmptyForIteratorPad"/>
    <module name="GenericWhitespace"/>
    <module name="MethodParamPad"/>
    <module name="NoWhitespaceAfter"/>
    <module name="NoWhitespaceBefore">
      <property name="allowLineBreaks" value="true"/>
    </module>
    <module name="ParenPad"/>
    <module name="TypecastParenPad"/>
    <module name="WhitespaceAfter"/>
    <module name="WhitespaceAround"/>

    <module name="EmptyLineSeparator"/>

    <!-- Modifier Checks                                    -->
    <!-- See https://checkstyle.org/config_modifier.html -->
    <module name="ModifierOrder"/>
    <module name="RedundantModifier"/>

    <!-- Checks for blocks. You know, those {}'s         -->
    <!-- See https://checkstyle.org/config_blocks.html -->
    <module name="AvoidNestedBlocks"/>
    <module name="EmptyBlock"/>
    <module name="LeftCurly"/>
    <module name="NeedBraces"/>
    <module name="RightCurly"/>

    <!-- Checks for common coding problems               -->
    <!-- See https://checkstyle.org/config_coding.html -->
    <module name="EmptyStatement"/>
    <module name="EqualsHashCode"/>
    <module name="HiddenField">
      <property name="ignoreConstructorParameter" value="true"/>
      <property name="ignoreSetter" value="true"/>
      <property name="setterCanReturnItsClass" value="true"/>
      <property name="tokens" value="PATTERN_VARIABLE_DEF, LAMBDA, RECORD_COMPONENT_DEF"/>
    </module>
    <module name="IllegalInstantiation"/>
    <module name="MagicNumber">
      <property name="ignoreNumbers" value="-1, 0, 1, 2, 3, 4, 255, 65535, 4294967295"/>
    </module>
    <module name="MultipleVariableDeclarations"/>
    <module name="SimplifyBooleanExpression"/>
    <module name="SimplifyBooleanReturn"/>
    <module name="NestedIfDepth">
      <property name="max" value="2"/>
    </module>
    <module name="NestedTryDepth">
    </module>
    <module name="NestedForDepth">
    </module>

    <!-- Checks for class design                         -->
    <!-- See https://checkstyle.org/config_design.html -->
    <module name="HideUtilityClassConstructor"/>
    <module name="InterfaceIsType"/>
    <module name="VisibilityModifier">
      <property name="protectedAllowed" value="true"/>
      <property name="allowPublicFinalFields" value="true"/>
    </module>

    <module name="FinalLocalVariable"/>

    <!-- Miscellaneous other checks.                   -->
    <!-- See https://checkstyle.org/config_misc.html -->
    <module name="ArrayTypeStyle"/>

    <module name="UpperEll"/>
  </module>
</module>