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.util.EventListener;
  
  /**
   * Listener in charge of receiving events from the Checker.
   * Typical events sequence is:
   * <pre>
   * auditStarted
   *   (fileStarted
   *     (addError)*
   *   fileFinished )*
   * auditFinished
   * </pre>
   */
  public interface AuditListener
      extends EventListener {
  
      /**
       * Notify that the audit is about to start.
       *
       * @param event the event details
       */
      void auditStarted(AuditEvent event);
  
      /**
       * Notify that the audit is finished.
       *
       * @param event the event details
       */
      void auditFinished(AuditEvent event);
  
      /**
       * Notify that audit is about to start on a specific file.
       *
       * @param event the event details
       */
      void fileStarted(AuditEvent event);
  
      /**
       * Notify that audit is finished on a specific file.
       *
       * @param event the event details
       */
      void fileFinished(AuditEvent event);
  
      /**
       * Notify that an audit error was discovered on a specific file.
       *
       * @param event the event details
       */
      void addError(AuditEvent event);
  
      /**
       * Notify that an exception happened while performing audit.
       *
       * @param event the event details
       * @param throwable details of the exception
       */
      void addException(AuditEvent event, Throwable throwable);
  
  }
  