001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.vfs2;
018
019/**
020 * Listens for changes to a file.
021 */
022public interface FileListener {
023    /**
024     * Called when a file is created.
025     *
026     * @param event The FileChangeEvent.
027     * @throws Exception if an error occurs.
028     */
029    void fileCreated(FileChangeEvent event) throws Exception;
030
031    /**
032     * Called when a file is deleted.
033     *
034     * @param event The FileChangeEvent.
035     * @throws Exception if an error occurs.
036     */
037    void fileDeleted(FileChangeEvent event) throws Exception;
038
039    /**
040     * Called when a file is changed.
041     * <p>
042     * This will only happen if you monitor the file using {@link FileMonitor}.
043     *
044     * @param event The FileChangeEvent.
045     * @throws Exception if an error occurs.
046     */
047    void fileChanged(FileChangeEvent event) throws Exception;
048}