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.meta;
  
  import java.io.File;
  import java.io.IOException;
  import java.io.OutputStream;
  import java.nio.charset.StandardCharsets;
  import java.nio.file.Files;
  import java.nio.file.Path;
  import java.nio.file.Paths;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.stream.Collectors;
  import java.util.stream.Stream;
  
  import com.puppycrawl.tools.checkstyle.AbstractAutomaticBean.OutputStreamOptions;
  import com.puppycrawl.tools.checkstyle.Checker;
  import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
  import com.puppycrawl.tools.checkstyle.MetadataGeneratorLogger;
  import com.puppycrawl.tools.checkstyle.TreeWalker;
  import com.puppycrawl.tools.checkstyle.api.CheckstyleException;
  import com.puppycrawl.tools.checkstyle.api.RootModule;
  
  /** Class which handles all the metadata generation and writing calls. */
  public final class MetadataGeneratorUtil {
  
      /** Stop instances being created. **/
      private MetadataGeneratorUtil() {
      }
  
      /**
       * Generate metadata from the module source files available in the input argument path.
       *
       * @param path arguments
       * @param out OutputStream for error messages
       * @param moduleFolders folders to check
       * @throws IOException ioException
       * @throws CheckstyleException checkstyleException
       */
      public static void generate(String path, OutputStream out, String... moduleFolders)
              throws IOException, CheckstyleException {
          JavadocMetadataScraper.resetModuleDetailsStore();
  
          final Checker checker = new Checker();
          checker.setModuleClassLoader(Checker.class.getClassLoader());
          final DefaultConfiguration scraperCheckConfig =
                          new DefaultConfiguration(JavadocMetadataScraper.class.getName());
          final DefaultConfiguration defaultConfiguration =
                  new DefaultConfiguration("configuration");
          final DefaultConfiguration treeWalkerConfig =
                  new DefaultConfiguration(TreeWalker.class.getName());
          defaultConfiguration.addProperty("charset", StandardCharsets.UTF_8.name());
          defaultConfiguration.addChild(treeWalkerConfig);
          treeWalkerConfig.addChild(scraperCheckConfig);
          checker.configure(defaultConfiguration);
  
          checker.addListener(new MetadataGeneratorLogger(out, OutputStreamOptions.NONE));
  
          dumpMetadata(checker, path, moduleFolders);
      }
  
      /**
       * Process files using the checker passed and write to corresponding XML files.
       *
       * @param moduleFolders folders to check
       * @param root root module
       * @param path rootPath
       * @throws CheckstyleException checkstyleException
       * @throws IOException ioException
       */
      private static void dumpMetadata(RootModule root, String path, String... moduleFolders)
              throws CheckstyleException,
              IOException {
          final List<File> validFiles = new ArrayList<>();
          for (String folder : moduleFolders) {
              try (Stream<Path> files = Files.walk(Paths.get(path
                      + "/" + folder))) {
                  validFiles.addAll(
                          files.map(Path::toFile)
                          .filter(file -> {
                              final String fileName = file.getName();
                              return fileName.endsWith("SuppressWarningsHolder.java")
                                      || fileName.endsWith("Check.java")
                                      || fileName.endsWith("Filter.java");
                          })
                          .collect(Collectors.toList()));
              }
          }
          root.process(validFiles);
      }
  }
  