code: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You under the Apache License, Version 2.0
   * (the "License"); you may not use this file except in compliance with
   * the License.  You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.apache.commons.io.monitor;
  import java.io.File;
  
  /**
   * A listener that receives events of file system modifications.
   * <p>
   * Register {@link FileAlterationListener}s with a {@link FileAlterationObserver}.
   * 
   * @see FileAlterationObserver
   * @version $Id: FileAlterationListener.java,v 1.1.2.1 2011/01/15 20:32:25 caniszczyk Exp $
   * @since Commons IO 2.0
   */
  public interface FileAlterationListener {
  
      /**
       * File system observer started checking event.
       *
       * @param observer The file system observer
       */
      void onStart(final FileAlterationObserver observer);
  
      /**
       * Directory created Event.
       * 
       * @param directory The directory created
       */
      void onDirectoryCreate(final File directory);
  
      /**
       * Directory changed Event.
       * 
       * @param directory The directory changed
       */
      void onDirectoryChange(final File directory);
  
      /**
       * Directory deleted Event.
       * 
       * @param directory The directory deleted
       */
      void onDirectoryDelete(final File directory);
  
      /**
       * File created Event.
       * 
       * @param file The file created
       */
      void onFileCreate(final File file);
  
      /**
       * File changed Event.
       * 
       * @param file The file changed
       */
      void onFileChange(final File file);
  
      /**
       * File deleted Event.
       * 
       * @param file The file deleted
       */
      void onFileDelete(final File file);
  
      /**
       * File system observer finished checking event.
       *
       * @param observer The file system observer
       */
      void onStop(final FileAlterationObserver observer);
  }
  