1 /**
2 * This file Copyright (c) 2014-2015 Magnolia International
3 * Ltd. (http://www.magnolia-cms.com). All rights reserved.
4 *
5 *
6 * This file is dual-licensed under both the Magnolia
7 * Network Agreement and the GNU General Public License.
8 * You may elect to use one or the other of these licenses.
9 *
10 * This file is distributed in the hope that it will be
11 * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
12 * implied warranty of MERCHANTABILITY or FITNESS FOR A
13 * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
14 * Redistribution, except as permitted by whichever of the GPL
15 * or MNA you select, is prohibited.
16 *
17 * 1. For the GPL license (GPL), you can redistribute and/or
18 * modify this file under the terms of the GNU General
19 * Public License, Version 3, as published by the Free Software
20 * Foundation. You should have received a copy of the GNU
21 * General Public License, Version 3 along with this program;
22 * if not, write to the Free Software Foundation, Inc., 51
23 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
24 *
25 * 2. For the Magnolia Network Agreement (MNA), this file
26 * and the accompanying materials are made available under the
27 * terms of the MNA which accompanies this distribution, and
28 * is available at http://www.magnolia-cms.com/mna.html
29 *
30 * Any modifications to this file must keep this entire header
31 * intact.
32 *
33 */
34 package info.magnolia.dirwatch;
35
36 import java.io.IOException;
37 import java.nio.file.Path;
38 import java.util.concurrent.ExecutorService;
39 import java.util.concurrent.Executors;
40 import java.util.concurrent.Future;
41 import java.util.concurrent.TimeUnit;
42
43 import javax.inject.Singleton;
44
45 import org.slf4j.Logger;
46 import org.slf4j.LoggerFactory;
47
48 import com.google.common.base.Predicate;
49
50 /**
51 * Service to watch for added and removed files and especially for file changes.
52 * <p>
53 * This creates a {@link DirectoryWatcher}, i.e. our low-level implementation of Java's {@link java.nio.file.WatchService WatchService} API.
54 * This watcher is then only started (submitted for execution) upon first request to register a directory.
55 */
56 @Singleton
57 public class DirectoryWatcherService {
58
59 private static final Logger log = LoggerFactory.getLogger(DirectoryWatcherService.class);
60
61 private static final boolean RECURSIVE = true;
62 private static final boolean FOLLOW_LINKS = true;
63
64 private final ExecutorService executorService;
65 private final DirectoryWatcher watcher;
66
67 private Future<?> watcherFuture;
68
69 public DirectoryWatcherService() throws IOException {
70 // We intentionally use a single thread executor (gather all registrations on a single DirectoryWatcher)
71 this.executorService = Executors.newSingleThreadExecutor();
72 this.watcher = new DirectoryWatcher(RECURSIVE, FOLLOW_LINKS);
73 }
74
75 public void start() {
76 }
77
78 /**
79 * Registers a directory to the {@link DirectoryWatcher}, with given filtering predicate and callback.
80 */
81 public synchronized void register(Path path, Predicate<Path> filterPredicate, WatcherCallback callback) throws IOException {
82 if (watcherFuture == null) {
83 log.info("Starting DirectoryWatcher");
84 watcherFuture = executorService.submit(watcher);
85 }
86 watcher.register(path, filterPredicate, callback);
87 }
88
89 public void stop() {
90 executorService.shutdownNow();
91
92 boolean terminated = false;
93 try {
94 terminated = executorService.awaitTermination(1, TimeUnit.SECONDS);
95 } catch (InterruptedException e) {
96 log.error("Exception during service termination", e);
97 }
98 if (terminated) {
99 log.info("{} terminated.", getClass().getSimpleName());
100 } else {
101 log.warn("{} not terminated, some tasks are still running.", getClass().getSimpleName());
102 }
103 }
104
105 }