001/*
002 * This file is part of McIDAS-V
003 *
004 * Copyright 2007-2016
005 * Space Science and Engineering Center (SSEC)
006 * University of Wisconsin - Madison
007 * 1225 W. Dayton Street, Madison, WI 53706, USA
008 * https://www.ssec.wisc.edu/mcidas
009 * 
010 * All Rights Reserved
011 * 
012 * McIDAS-V is built on Unidata's IDV and SSEC's VisAD libraries, and
013 * some McIDAS-V source code is based on IDV and VisAD source code.  
014 * 
015 * McIDAS-V is free software; you can redistribute it and/or modify
016 * it under the terms of the GNU Lesser Public License as published by
017 * the Free Software Foundation; either version 3 of the License, or
018 * (at your option) any later version.
019 * 
020 * McIDAS-V is distributed in the hope that it will be useful,
021 * but WITHOUT ANY WARRANTY; without even the implied warranty of
022 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
023 * GNU Lesser Public License for more details.
024 * 
025 * You should have received a copy of the GNU Lesser Public License
026 * along with this program.  If not, see http://www.gnu.org/licenses.
027 */
028
029package edu.wisc.ssec.mcidasv.util.pathwatcher;
030
031import java.io.IOException;
032
033// Taken from https://gist.github.com/hindol-viz/394ebc553673e2cd0699
034
035/**
036 * Interface definition of a simple directory watch service.
037 *
038 * Implementations of this interface allow interested parties to
039 * <em>listen</em> to file system events coming from a specific directory.
040 */
041public interface DirectoryWatchService extends Service {
042
043    @Override void start(); /* Suppress Exception */
044
045    /**
046     * Notifies the implementation of <em>this</em> interface that
047     * {@code dirPath} should be monitored for file system events. If the
048     * changed file matches any of the {@code globPatterns}, {@code listener}
049     * should be notified.
050     *
051     * @param listener The listener.
052     * @param dirPath The directory path.
053     * @param globPatterns Zero or more file patterns to be matched against
054     *                     file names. If none provided, matches <em>any</em>
055     *                     file.
056     *
057     * @throws IOException If {@code dirPath} is not a directory.
058     */
059    void register(OnFileChangeListener listener, String dirPath,
060                  String... globPatterns)
061            throws IOException;
062
063    /**
064     * Notifies the implementation of <em>this</em> interface that
065     * {@code listener} should cease to be notified of file system events.
066     *
067     * @param listener Listener to unregister. Cannot be {@code null}.
068     */
069    void unregister(OnFileChangeListener listener);
070
071    /**
072     * Unregisters <em>all</em> listeners.
073     */
074    void unregisterAll();
075
076}