code: ///////////////////////////////////////////////////////////////////////////////////////////////
  // checkstyle: Checks Java source code and other text files for adherence to a set of rules.
  // Copyright (C) 2001-2023 the original author or authors.
  //
  // This library is free software; you can redistribute it and/or
  // modify it under the terms of the GNU Lesser General Public
  // License as published by the Free Software Foundation; either
  // version 2.1 of the License, or (at your option) any later version.
  //
  // This library 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
  // Lesser General Public License for more details.
  //
  // You should have received a copy of the GNU Lesser General Public
  // License along with this library; if not, write to the Free Software
  // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  ///////////////////////////////////////////////////////////////////////////////////////////////
  
  package com.puppycrawl.tools.checkstyle.utils;
  
  import static com.google.common.truth.Truth.assertWithMessage;
  import static com.puppycrawl.tools.checkstyle.internal.utils.TestUtil.isUtilsClassHasPrivateConstructor;
  
  import java.io.File;
  import java.util.List;
  
  import org.junit.jupiter.api.Test;
  
  import com.puppycrawl.tools.checkstyle.AbstractAutomaticBean;
  import com.puppycrawl.tools.checkstyle.DefaultLogger;
  import com.puppycrawl.tools.checkstyle.TreeWalkerAuditEvent;
  import com.puppycrawl.tools.checkstyle.TreeWalkerFilter;
  import com.puppycrawl.tools.checkstyle.XpathFileGeneratorAstFilter;
  import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
  import com.puppycrawl.tools.checkstyle.api.AbstractFileSetCheck;
  import com.puppycrawl.tools.checkstyle.api.AuditEvent;
  import com.puppycrawl.tools.checkstyle.api.AuditListener;
  import com.puppycrawl.tools.checkstyle.api.BeforeExecutionFileFilter;
  import com.puppycrawl.tools.checkstyle.api.FileText;
  import com.puppycrawl.tools.checkstyle.api.Filter;
  import com.puppycrawl.tools.checkstyle.api.RootModule;
  
  public class ModuleReflectionUtilTest {
  
      @Test
      public void testIsProperUtilsClass() throws ReflectiveOperationException {
          assertWithMessage("Constructor is not private")
                  .that(isUtilsClassHasPrivateConstructor(ModuleReflectionUtil.class))
                  .isTrue();
      }
  
      @Test
      public void testIsCheckstyleModule() {
          assertWithMessage("Should return true when checkstyle module is passed")
                  .that(ModuleReflectionUtil.isCheckstyleModule(CheckClass.class))
                  .isTrue();
          assertWithMessage("Should return true when checkstyle module is passed")
                  .that(ModuleReflectionUtil.isCheckstyleModule(FileSetModuleClass.class))
                  .isTrue();
          assertWithMessage("Should return true when checkstyle module is passed")
                  .that(ModuleReflectionUtil.isCheckstyleModule(FilterClass.class))
                  .isTrue();
          assertWithMessage("Should return true when checkstyle module is passed")
                  .that(ModuleReflectionUtil.isCheckstyleModule(TreeWalkerFilterClass.class))
                  .isTrue();
          assertWithMessage("Should return true when checkstyle module is passed")
                  .that(ModuleReflectionUtil.isCheckstyleModule(FileFilterModuleClass.class))
                  .isTrue();
          assertWithMessage("Should return true when checkstyle module is passed")
                  .that(ModuleReflectionUtil.isCheckstyleModule(AuditListenerClass.class))
                  .isTrue();
          assertWithMessage("Should return true when checkstyle module is passed")
                  .that(ModuleReflectionUtil.isCheckstyleModule(RootModuleClass.class))
                  .isTrue();
      }
  
      @Test
      public void testIsValidCheckstyleClass() {
          assertWithMessage("Should return true when valid checkstyle class is passed")
                  .that(ModuleReflectionUtil.isCheckstyleModule(ValidCheckstyleClass.class))
                  .isTrue();
          assertWithMessage("Should return false when invalid class is passed")
                  .that(
                      ModuleReflectionUtil.isCheckstyleModule(InvalidNonAutomaticBeanClass.class))
                  .isFalse();
          assertWithMessage("Should return false when invalid class is passed")
                  .that(ModuleReflectionUtil.isCheckstyleModule(AbstractInvalidClass.class))
                  .isFalse();
          assertWithMessage("Should return false when invalid class is passed")
                  .that(ModuleReflectionUtil
                      .isCheckstyleModule(InvalidNonDefaultConstructorClass.class))
                  .isFalse();
          assertWithMessage("Should return false when forced invalid class is passed")
                  .that(
                      ModuleReflectionUtil.isCheckstyleModule(XpathFileGeneratorAstFilter.class))
                  .isFalse();
      }
  
      @Test
      public void testIsCheckstyleCheck() {
          assertWithMessage("Should return true when valid checkstyle check is passed")
                  .that(ModuleReflectionUtil.isCheckstyleTreeWalkerCheck(CheckClass.class))
                  .isTrue();
          assertWithMessage("Should return false when invalid class is passed")
                  .that(ModuleReflectionUtil.isCheckstyleTreeWalkerCheck(NotCheckstyleCheck.class))
                  .isFalse();
      }
  
      @Test
      public void testIsFileSetModule() {
          assertWithMessage("Should return true when valid checkstyle file set module is passed")
                  .that(ModuleReflectionUtil.isFileSetModule(FileSetModuleClass.class))
                  .isTrue();
          assertWithMessage("Should return false when invalid class is passed")
                  .that(ModuleReflectionUtil.isFileSetModule(NotCheckstyleCheck.class))
                  .isFalse();
      }
  
      @Test
      public void testIsFilterModule() {
          assertWithMessage("Should return true when valid checkstyle filter module is passed")
                  .that(ModuleReflectionUtil.isFilterModule(FilterClass.class))
                  .isTrue();
          assertWithMessage("Should return false when invalid class is passed")
                  .that(ModuleReflectionUtil.isFilterModule(NotCheckstyleCheck.class))
                  .isFalse();
      }
  
      @Test
      public void testIsFileFilterModule() {
          assertWithMessage("Should return true when valid checkstyle file filter module is passed")
                  .that(ModuleReflectionUtil.isFileFilterModule(FileFilterModuleClass.class))
                  .isTrue();
          assertWithMessage("Should return false when invalid class is passed")
                  .that(ModuleReflectionUtil.isFileFilterModule(NotCheckstyleCheck.class))
                  .isFalse();
      }
  
      @Test
      public void testIsTreeWalkerFilterModule() {
          assertWithMessage(
                      "Should return true when valid checkstyle TreeWalker filter module is passed")
                  .that(ModuleReflectionUtil.isTreeWalkerFilterModule(TreeWalkerFilterClass.class))
                  .isTrue();
          assertWithMessage("Should return false when invalid class is passed")
                  .that(ModuleReflectionUtil.isTreeWalkerFilterModule(NotCheckstyleCheck.class))
                  .isFalse();
      }
  
      @Test
      public void testIsAuditListener() {
          assertWithMessage("Should return true when valid checkstyle AuditListener module is passed")
                  .that(ModuleReflectionUtil.isAuditListener(DefaultLogger.class))
                  .isTrue();
          assertWithMessage("Should return false when invalid class is passed")
                  .that(ModuleReflectionUtil.isAuditListener(NotCheckstyleCheck.class))
                  .isFalse();
      }
  
      @Test
      public void testIsRootModule() {
          assertWithMessage("Should return true when valid checkstyle root module is passed")
                  .that(ModuleReflectionUtil.isRootModule(RootModuleClass.class))
                  .isTrue();
          assertWithMessage("Should return false when invalid class is passed")
                  .that(ModuleReflectionUtil.isRootModule(NotCheckstyleCheck.class))
                  .isFalse();
      }
  
      @Test
      public void testKeepEclipseHappy() {
          final InvalidNonDefaultConstructorClass test = new InvalidNonDefaultConstructorClass(0);
          assertWithMessage("should use constructor")
              .that(test)
              .isNotNull();
          assertWithMessage("should use field")
              .that(test.getField())
              .isEqualTo(1);
      }
  
      private static final class ValidCheckstyleClass extends AbstractAutomaticBean {
  
          // empty, use default constructor
  
          @Override
          protected void finishLocalSetup() {
              // dummy method
          }
  
      }
  
      private static final class InvalidNonAutomaticBeanClass {
  
          // empty, use default constructor
  
      }
  
      /**
       * AbstractInvalidClass.
       *
       * @noinspection AbstractClassNeverImplemented
       * @noinspectionreason AbstractClassNeverImplemented - class is only used in testing
       */
      private abstract static class AbstractInvalidClass extends AbstractAutomaticBean {
  
          public abstract void method();
  
      }
  
      private static final class CheckClass extends AbstractCheck {
  
          @Override
          public int[] getDefaultTokens() {
              return new int[] {0};
          }
  
          @Override
          public int[] getAcceptableTokens() {
              return getDefaultTokens();
          }
  
          @Override
          public int[] getRequiredTokens() {
              return getDefaultTokens();
          }
  
      }
  
      private static final class FileSetModuleClass extends AbstractFileSetCheck {
  
          @Override
          protected void processFiltered(File file, FileText fileText) {
              // dummy method
          }
  
      }
  
      private static final class FilterClass extends AbstractAutomaticBean implements Filter {
  
          @Override
          protected void finishLocalSetup() {
              // dummy method
          }
  
          @Override
          public boolean accept(AuditEvent event) {
              return false;
          }
  
      }
  
      private static final class FileFilterModuleClass extends AbstractAutomaticBean
              implements BeforeExecutionFileFilter {
  
          @Override
          protected void finishLocalSetup() {
              // dummy method
          }
  
          @Override
          public boolean accept(String uri) {
              return false;
          }
  
      }
  
      private static final class RootModuleClass extends AbstractAutomaticBean implements RootModule {
  
          @Override
          protected void finishLocalSetup() {
              // dummy method
          }
  
          @Override
          public void addListener(AuditListener listener) {
              // dummy method
          }
  
          @Override
          public int process(List<File> files) {
              return 0;
          }
  
          @Override
          public void destroy() {
              // dummy method
          }
  
          @Override
          public void setModuleClassLoader(ClassLoader moduleClassLoader) {
              // dummy method
          }
  
      }
  
      private static final class TreeWalkerFilterClass
              extends AbstractAutomaticBean implements TreeWalkerFilter {
  
          @Override
          protected void finishLocalSetup() {
              // dummy method
          }
  
          @Override
          public boolean accept(TreeWalkerAuditEvent treeWalkerAuditEvent) {
              return false;
          }
  
      }
  
      private static final class AuditListenerClass
              extends AbstractAutomaticBean implements AuditListener {
  
          @Override
          protected void finishLocalSetup() {
              // dummy method
          }
  
          @Override
          public void auditStarted(AuditEvent event) {
              // dummy method
          }
  
          @Override
          public void auditFinished(AuditEvent event) {
              // dummy method
          }
  
          @Override
          public void fileStarted(AuditEvent event) {
              // dummy method
          }
  
          @Override
          public void fileFinished(AuditEvent event) {
              // dummy method
          }
  
          @Override
          public void addError(AuditEvent event) {
              // dummy method
          }
  
          @Override
          public void addException(AuditEvent event, Throwable throwable) {
              // dummy method
          }
  
      }
  
      private static final class NotCheckstyleCheck {
  
          // empty, use default constructor
  
      }
  
      private static class InvalidNonDefaultConstructorClass extends AbstractAutomaticBean {
  
          private int field;
  
          protected InvalidNonDefaultConstructorClass(int data) {
              // keep pmd calm and happy
              field = 0;
              method(data);
          }
  
          public final void method(int data) {
              field++;
              if (data > 0) {
                  method(data - 1);
              }
          }
  
          public int getField() {
              return field;
          }
  
          @Override
          protected void finishLocalSetup() {
              // dummy method
          }
  
      }
  
  }
  