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.api;
  
  import java.io.File;
  import java.util.SortedSet;
  
  /**
   * Interface for Checking a set of files for some criteria.
   *
   */
  public interface FileSetCheck
      extends Configurable, Contextualizable {
  
      /**
       * Sets the MessageDispatcher that is used to dispatch audit events
       * to AuditListeners during processing.
       *
       * @param dispatcher the dispatcher
       */
      void setMessageDispatcher(MessageDispatcher dispatcher);
  
      /**
       * Initialise the instance. This is the time to verify that everything
       * required to perform its job.
       */
      void init();
  
      /** Cleans up the object. **/
      void destroy();
  
      /**
       * Called when about to be called to process a set of files.
       *
       * @param charset the character set used to read the files.
       */
      void beginProcessing(String charset);
  
      /**
       * Request to process a file. The implementation should use the supplied
       * contents and not read the contents again. This reduces the amount of
       * file I/O.
       * <p>
       * The file set to process might contain files that are not
       * interesting to the FileSetCheck. Such files should be ignored,
       * no audit event should be fired for them. For example a FileSetCheck
       * that checks java files should ignore HTML or properties files.
       * </p>
       * <p>
       * The method should return the set of violations to be logged.
       * </p>
       *
       * @param file the file to be processed
       * @param fileText the contents of the file.
       * @return the sorted set of violations to be logged.
       * @throws CheckstyleException if error condition within Checkstyle occurs
       */
      SortedSet<Violation> process(File file, FileText fileText) throws CheckstyleException;
  
      /**
       * Called when all the files have been processed. This is the time to
       * perform any checks that need to be done across a set of files. In this
       * method, the implementation is responsible for the logging of violations.
       */
      void finishProcessing();
  
  }
  