Test GitHub actions

.github/linters/checkstyle.xml

@@ -0,0 +1,199 @@
+<?xml version="1.0"?>
+<!DOCTYPE module PUBLIC
+          "-//Checkstyle//DTD Checkstyle Configuration 1.3//EN"
+          "https://checkstyle.org/dtds/configuration_1_3.dtd">
+
+<!--
+
+  Checkstyle configuration that checks the sun coding conventions from:
+
+    - the Java Language Specification at
+      https://docs.oracle.com/javase/specs/jls/se11/html/index.html
+
+    - the Sun Code Conventions at https://www.oracle.com/java/technologies/javase/codeconventions-contents.html
+
+    - the Javadoc guidelines at
+      https://www.oracle.com/technical-resources/articles/java/javadoc-tool.html
+
+    - the JDK Api documentation https://docs.oracle.com/en/java/javase/11/
+
+    - some best practices
+
+  Checkstyle is very configurable. Be sure to read the documentation at
+  https://checkstyle.org (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.
+  To suppress certain violations please review suppression filters.
+
+  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
+      https://checkstyle.org/config.html#Checker
+
+      <property name="basedir" value="${basedir}"/>
+  -->
+  <property name="severity" value="error"/>
+
+  <property name="fileExtensions" value="java, properties, xml"/>
+
+  <!-- Excludes all 'module-info.java' files              -->
+  <!-- See https://checkstyle.org/filefilters/index.html -->
+  <module name="BeforeExecutionExclusionFileFilter">
+    <property name="fileNamePattern" value="module\-info\.java$"/>
+  </module>
+
+  <!-- https://checkstyle.org/filters/suppressionfilter.html -->
+  <module name="SuppressionFilter">
+    <property name="file" value="${org.checkstyle.sun.suppressionfilter.config}"
+              default="checkstyle-suppressions.xml" />
+    <property name="optional" value="true"/>
+  </module>
+
+  <!-- Checks that a package-info.java file exists for each package.     -->
+  <!-- See https://checkstyle.org/checks/javadoc/javadocpackage.html#JavadocPackage -->
+  <module name="JavadocPackage"/>
+
+  <!-- Checks whether files end with a new line.                        -->
+  <!-- See https://checkstyle.org/checks/misc/newlineatendoffile.html -->
+  <module name="NewlineAtEndOfFile"/>
+
+  <!-- Checks that property files contain the same keys.         -->
+  <!-- See https://checkstyle.org/checks/misc/translation.html -->
+  <module name="Translation"/>
+
+  <!-- Checks for Size Violations.                    -->
+  <!-- See https://checkstyle.org/checks/sizes/index.html -->
+  <module name="FileLength"/>
+  <module name="LineLength">
+    <property name="fileExtensions" value="java"/>
+    <property name="max" value="120"/>
+  </module>
+
+  <!-- Checks for whitespace                               -->
+  <!-- See https://checkstyle.org/checks/whitespace/index.html -->
+  <module name="FileTabCharacter"/>
+
+  <!-- Miscellaneous other checks.                   -->
+  <!-- See https://checkstyle.org/checks/misc/index.html -->
+  <module name="RegexpSingleline">
+    <property name="format" value="\s+$"/>
+    <property name="minimum" value="0"/>
+    <property name="maximum" value="0"/>
+    <property name="message" value="Line has trailing spaces."/>
+  </module>
+
+  <!-- Checks for Headers                                -->
+  <!-- See https://checkstyle.org/checks/header/index.html   -->
+  <!-- <module name="Header"> -->
+  <!--   <property name="headerFile" value="${checkstyle.header.file}"/> -->
+  <!--   <property name="fileExtensions" value="java"/> -->
+  <!-- </module> -->
+
+  <module name="TreeWalker">
+
+    <!-- Checks for Javadoc comments.                     -->
+    <!-- See https://checkstyle.org/checks/javadoc/index.html -->
+    <module name="InvalidJavadocPosition"/>
+    <module name="JavadocMethod"/>
+    <module name="JavadocType"/>
+    <module name="JavadocVariable"/>
+    <module name="JavadocStyle"/>
+    <module name="MissingJavadocMethod"/>
+
+    <!-- Checks for Naming Conventions.                  -->
+    <!-- See https://checkstyle.org/checks/naming/index.html -->
+    <module name="ConstantName"/>
+    <module name="LocalFinalVariableName"/>
+    <module name="LocalVariableName"/>
+    <module name="MemberName"/>
+    <module name="MethodName"/>
+    <module name="PackageName"/>
+    <module name="ParameterName"/>
+    <module name="StaticVariableName"/>
+    <module name="TypeName"/>
+
+    <!-- Checks for imports                              -->
+    <!-- See https://checkstyle.org/checks/imports/index.html -->
+    <module name="AvoidStarImport"/>
+    <module name="IllegalImport"/> <!-- defaults to sun.* packages -->
+    <module name="RedundantImport"/>
+    <module name="UnusedImports">
+      <property name="processJavadoc" value="false"/>
+    </module>
+
+    <!-- Checks for Size Violations.                    -->
+    <!-- See https://checkstyle.org/checks/sizes/index.html -->
+    <module name="MethodLength"/>
+    <module name="ParameterNumber"/>
+
+    <!-- Checks for whitespace                               -->
+    <!-- See https://checkstyle.org/checks/whitespace/index.html -->
+    <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"/>
+
+    <!-- Modifier Checks                                    -->
+    <!-- See https://checkstyle.org/checks/modifier/index.html -->
+    <module name="ModifierOrder"/>
+    <module name="RedundantModifier"/>
+
+    <!-- Checks for blocks. You know, those {}'s         -->
+    <!-- See https://checkstyle.org/checks/blocks/index.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/checks/coding/index.html -->
+    <module name="EmptyStatement"/>
+    <module name="EqualsHashCode"/>
+    <module name="HiddenField"/>
+    <module name="IllegalInstantiation"/>
+    <module name="InnerAssignment"/>
+    <module name="MagicNumber"/>
+    <module name="MissingSwitchDefault"/>
+    <module name="MultipleVariableDeclarations"/>
+    <module name="SimplifyBooleanExpression"/>
+    <module name="SimplifyBooleanReturn"/>
+
+    <!-- Checks for class design                         -->
+    <!-- See https://checkstyle.org/checks/design/index.html -->
+    <module name="DesignForExtension"/>
+    <module name="FinalClass"/>
+    <module name="HideUtilityClassConstructor"/>
+    <module name="InterfaceIsType"/>
+    <module name="VisibilityModifier"/>
+
+    <!-- Miscellaneous other checks.                   -->
+    <!-- See https://checkstyle.org/checks/misc/index.html -->
+    <module name="ArrayTypeStyle"/>
+    <module name="FinalParameters"/>
+    <module name="TodoComment"/>
+    <module name="UpperEll"/>
+
+    <!-- https://checkstyle.org/filters/suppressionxpathfilter.html -->
+    <module name="SuppressionXpathFilter">
+      <property name="file" value="${org.checkstyle.sun.suppressionxpathfilter.config}"
+                default="checkstyle-xpath-suppressions.xml" />
+      <property name="optional" value="true"/>
+    </module>
+
+  </module>
+
+</module>

.github/workflows/linter.yml

@@ -0,0 +1,35 @@
+name: Lint Code Base
+on:
+  push:
+    branches-ignore: [master, main]
+  pull_request:
+    branches: [master, main]
+jobs:
+  build:
+    name: Lint
+    runs-on: ubuntu-latest
+
+    permissions:
+      contents: read
+      packages: read
+      # To report GitHub Actions status checks
+      statuses: write
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+        with:
+          # super-linter needs the full git history to get the
+          # list of files that changed across commits
+          fetch-depth: 0
+
+      - name: Super-linter
+        uses: super-linter/[email protected] # x-release-please-version
+        env:
+          # To report GitHub Actions status checks
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          VALIDATE_JAVA: true
+          FILTER_REGEX_INCLUDE: .*src/.*/ # Only lint files in src/
+          LINTER_RULES_PATH: .github/linters
+          JAVA_FILE_NAME: checkstyle.xml
+