19066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project/* 29066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * Copyright (C) 2006 The Android Open Source Project 39066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * 49066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * Licensed under the Apache License, Version 2.0 (the "License"); 59066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * you may not use this file except in compliance with the License. 69066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * You may obtain a copy of the License at 79066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * 89066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * http://www.apache.org/licenses/LICENSE-2.0 99066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * 109066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * Unless required by applicable law or agreed to in writing, software 119066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * distributed under the License is distributed on an "AS IS" BASIS, 129066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 139066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * See the License for the specific language governing permissions and 149066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * limitations under the License. 159066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project */ 169066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project 179066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Projectpackage android.os; 189066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project 19c041f5a3b835242fee920c16b5ba6b48e72de007Jeff Sharkeyimport android.annotation.Nullable; 209066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Projectimport android.util.Log; 219066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project 229066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Projectimport java.lang.ref.WeakReference; 239066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Projectimport java.util.HashMap; 249066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project 253dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor/** 263dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * Monitors files (using <a href="http://en.wikipedia.org/wiki/Inotify">inotify</a>) 273dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * to fire an event after files are accessed or changed by by any process on 283dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * the device (including this one). FileObserver is an abstract class; 293dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * subclasses must implement the event handler {@link #onEvent(int, String)}. 303dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * 313dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * <p>Each FileObserver instance monitors a single file or directory. 323dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * If a directory is monitored, events will be triggered for all files and 336aad995042599dd0f5def79fea85cee90439c9a8Scott Main * subdirectories inside the monitored directory.</p> 343dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * 353dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * <p>An event mask is used to specify which changes or actions to report. 363dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * Event type constants are used to describe the possible changes in the 373dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * event mask as well as what actually happened in event callbacks.</p> 383dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * 393dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * <p class="caution"><b>Warning</b>: If a FileObserver is garbage collected, it 403dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * will stop sending events. To ensure you keep receiving events, you must 413dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * keep a reference to the FileObserver instance from some other live object.</p> 423dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor */ 439066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Projectpublic abstract class FileObserver { 443dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor /** Event type: Data was read from a file */ 459bb8fd77c8dc177aab9ac96bed4f55972dcda70aJoe Onorato public static final int ACCESS = 0x00000001; 463dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor /** Event type: Data was written to a file */ 479bb8fd77c8dc177aab9ac96bed4f55972dcda70aJoe Onorato public static final int MODIFY = 0x00000002; 483dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor /** Event type: Metadata (permissions, owner, timestamp) was changed explicitly */ 499bb8fd77c8dc177aab9ac96bed4f55972dcda70aJoe Onorato public static final int ATTRIB = 0x00000004; 503dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor /** Event type: Someone had a file or directory open for writing, and closed it */ 519bb8fd77c8dc177aab9ac96bed4f55972dcda70aJoe Onorato public static final int CLOSE_WRITE = 0x00000008; 523dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor /** Event type: Someone had a file or directory open read-only, and closed it */ 539bb8fd77c8dc177aab9ac96bed4f55972dcda70aJoe Onorato public static final int CLOSE_NOWRITE = 0x00000010; 543dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor /** Event type: A file or directory was opened */ 559bb8fd77c8dc177aab9ac96bed4f55972dcda70aJoe Onorato public static final int OPEN = 0x00000020; 563dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor /** Event type: A file or subdirectory was moved from the monitored directory */ 579bb8fd77c8dc177aab9ac96bed4f55972dcda70aJoe Onorato public static final int MOVED_FROM = 0x00000040; 583dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor /** Event type: A file or subdirectory was moved to the monitored directory */ 599bb8fd77c8dc177aab9ac96bed4f55972dcda70aJoe Onorato public static final int MOVED_TO = 0x00000080; 603dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor /** Event type: A new file or subdirectory was created under the monitored directory */ 619bb8fd77c8dc177aab9ac96bed4f55972dcda70aJoe Onorato public static final int CREATE = 0x00000100; 623dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor /** Event type: A file was deleted from the monitored directory */ 639bb8fd77c8dc177aab9ac96bed4f55972dcda70aJoe Onorato public static final int DELETE = 0x00000200; 643dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor /** Event type: The monitored file or directory was deleted; monitoring effectively stops */ 659bb8fd77c8dc177aab9ac96bed4f55972dcda70aJoe Onorato public static final int DELETE_SELF = 0x00000400; 663dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor /** Event type: The monitored file or directory was moved; monitoring continues */ 679bb8fd77c8dc177aab9ac96bed4f55972dcda70aJoe Onorato public static final int MOVE_SELF = 0x00000800; 689bb8fd77c8dc177aab9ac96bed4f55972dcda70aJoe Onorato 693dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor /** Event mask: All valid event types, combined */ 703dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor public static final int ALL_EVENTS = ACCESS | MODIFY | ATTRIB | CLOSE_WRITE 719066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project | CLOSE_NOWRITE | OPEN | MOVED_FROM | MOVED_TO | DELETE | CREATE 72d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor | DELETE_SELF | MOVE_SELF; 739bb8fd77c8dc177aab9ac96bed4f55972dcda70aJoe Onorato 749066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project private static final String LOG_TAG = "FileObserver"; 759066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project 769066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project private static class ObserverThread extends Thread { 77d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor private HashMap<Integer, WeakReference> m_observers = new HashMap<Integer, WeakReference>(); 78d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor private int m_fd; 79d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor 80d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor public ObserverThread() { 81d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor super("FileObserver"); 82d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor m_fd = init(); 83d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor } 84d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor 85d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor public void run() { 86d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor observe(m_fd); 87d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor } 88d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor 89d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor public int startWatching(String path, int mask, FileObserver observer) { 90d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor int wfd = startWatching(m_fd, path, mask); 91d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor 92d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor Integer i = new Integer(wfd); 93d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor if (wfd >= 0) { 94d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor synchronized (m_observers) { 95d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor m_observers.put(i, new WeakReference(observer)); 96d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor } 979066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project } 98d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor 99d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor return i; 1009066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project } 1019066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project 102d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor public void stopWatching(int descriptor) { 103d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor stopWatching(m_fd, descriptor); 104d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor } 105d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor 106d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor public void onEvent(int wfd, int mask, String path) { 107d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor // look up our observer, fixing up the map if necessary... 108d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor FileObserver observer = null; 109d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor 110d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor synchronized (m_observers) { 111d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor WeakReference weak = m_observers.get(wfd); 112d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor if (weak != null) { // can happen with lots of events from a dead wfd 113d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor observer = (FileObserver) weak.get(); 114d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor if (observer == null) { 115d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor m_observers.remove(wfd); 116d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor } 117d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor } 118d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor } 119d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor 120d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor // ...then call out to the observer without the sync lock held 121d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor if (observer != null) { 122d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor try { 123d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor observer.onEvent(mask, path); 124d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor } catch (Throwable throwable) { 125d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor Log.wtf(LOG_TAG, "Unhandled exception in FileObserver " + observer, throwable); 126d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor } 1279066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project } 1289066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project } 1299066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project 130d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor private native int init(); 131d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor private native void observe(int fd); 132d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor private native int startWatching(int fd, String path, int mask); 133d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor private native void stopWatching(int fd, int wfd); 1349066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project } 1359066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project 1369066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project private static ObserverThread s_observerThread; 1379066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project 1389066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project static { 139d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor s_observerThread = new ObserverThread(); 140d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor s_observerThread.start(); 1419066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project } 1429066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project 1439066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project // instance 1449066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project private String m_path; 1459066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project private Integer m_descriptor; 1469066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project private int m_mask; 1479066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project 1483dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor /** 1493dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * Equivalent to FileObserver(path, FileObserver.ALL_EVENTS). 1503dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor */ 1519066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project public FileObserver(String path) { 152d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor this(path, ALL_EVENTS); 1539066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project } 1549066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project 1553dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor /** 1563dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * Create a new file observer for a certain file or directory. 1573dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * Monitoring does not start on creation! You must call 1583dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * {@link #startWatching()} before you will receive events. 1593dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * 1603dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * @param path The file or directory to monitor 1613dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * @param mask The event or events (added together) to watch for 1623dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor */ 1639066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project public FileObserver(String path, int mask) { 164d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor m_path = path; 165d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor m_mask = mask; 166d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor m_descriptor = -1; 1679066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project } 1689066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project 1699066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project protected void finalize() { 170d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor stopWatching(); 1719066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project } 1729066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project 1733dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor /** 1743dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * Start watching for events. The monitored file or directory must exist at 1753dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * this time, or else no events will be reported (even if it appears later). 1763dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * If monitoring is already started, this call has no effect. 1773dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor */ 1789066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project public void startWatching() { 179d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor if (m_descriptor < 0) { 180d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor m_descriptor = s_observerThread.startWatching(m_path, m_mask, this); 181d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor } 1829066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project } 1839066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project 1843dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor /** 1853dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * Stop watching for events. Some events may be in process, so events 1863dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * may continue to be reported even after this method completes. If 1873dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * monitoring is already stopped, this call has no effect. 1883dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor */ 1899066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project public void stopWatching() { 190d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor if (m_descriptor >= 0) { 191d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor s_observerThread.stopWatching(m_descriptor); 192d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor m_descriptor = -1; 193d95244faef7b54fe46223aec1ed5754cd9b74a3eDan Egnor } 1949066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project } 1959066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project 1963dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor /** 1973dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * The event handler, which must be implemented by subclasses. 1983dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * 1993dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * <p class="note">This method is invoked on a special FileObserver thread. 2003dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * It runs independently of any threads, so take care to use appropriate 2013dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * synchronization! Consider using {@link Handler#post(Runnable)} to shift 2023dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * event handling work to the main thread to avoid concurrency problems.</p> 2033dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * 2043dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * <p>Event handlers must not throw exceptions.</p> 2053dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * 2063dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * @param event The type of event which happened 2073dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor * @param path The path, relative to the main monitored file or directory, 208c041f5a3b835242fee920c16b5ba6b48e72de007Jeff Sharkey * of the file or directory which triggered the event. This value can 209c041f5a3b835242fee920c16b5ba6b48e72de007Jeff Sharkey * be {@code null} for certain events, such as {@link #MOVE_SELF}. 2103dc1c7f5e84a888bc0a3aee764e9c6fa01395d8aDan Egnor */ 211c041f5a3b835242fee920c16b5ba6b48e72de007Jeff Sharkey public abstract void onEvent(int event, @Nullable String path); 2129066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project} 213