public static void watchDirectoryPath(Path path) {
// Sanity check - Check if path is a folder
try {
Boolean isFolder = (Boolean) Files.getAttribute(path, "basic:isDirectory", NOFOLLOW_LINKS);
if (!isFolder) {
throw new IllegalArgumentException("Path: " + path + " is not a folder");
}
} catch (IOException ioe) {
// Folder does not exists
ioe.printStackTrace();
}
// System.out.println("Watching path: " + path);
// We obtain the file system of the Path
FileSystem fs = path.getFileSystem();
// We create the new WatchService using the new try() block
try (WatchService service = fs.newWatchService()) {
// We register the path to the service
// We watch for creation events
path.register(service, ENTRY_CREATE);
// Start the infinite polling loop
WatchKey key = null;
while (true) {
key = service.take();
// Dequeueing events
Kind<?> kind = null;
for (WatchEvent<?> watchEvent : key.pollEvents()) {
// Get the type of the event
kind = watchEvent.kind();
if (OVERFLOW == kind) {
continue; // loop
} else if (ENTRY_CREATE == kind) {
// A new Path was created
// Path newPath = ((WatchEvent<Path>)
// watchEvent).context();
// Output
// System.out.println("New path created: " + newPath);
}
}
if (!key.reset()) {
break; // loop
}
}
} catch (IOException ioe) {
ioe.printStackTrace();
} catch (InterruptedException ie) {
ie.printStackTrace();
}
}
public static void watchDirectoryPath(Path path) {
if (path != null) {
System.out.println("Watching path: " + path);
FileSystem fs = path.getFileSystem();
try (WatchService service = fs.newWatchService()) {
path.register(service, ENTRY_CREATE);
WatchKey key;
while (true) {
key = service.take();
// Dequeueing events
Kind<?> kind;
for (WatchEvent<?> watchEvent : key.pollEvents()) {
// Get the type of the event
kind = watchEvent.kind();
if (OVERFLOW == kind) {
continue; // loop
} else if (ENTRY_CREATE == kind) {
// A new Path was created
Path newPath = ((WatchEvent<Path>) watchEvent).context();
// Output
System.out.println("New path created/modified: " + newPath);
checkPath(newPath.toString());
}
}
if (!key.reset()) {
break; // resets the key so it continues to look for new creation events.
}
}
} catch (IOException | InterruptedException ioe) {
System.out.println("The file watcher was interrupted.");
}
}
}
public Settings(File configFile) throws IllegalArgumentException, IOException {
this.propertiesFile = configFile;
reload();
synchronized (watchKeys) {
if (watchKeys.isEmpty()) {
FileSystem fs = FileSystems.getDefault();
watchService = fs.newWatchService();
backgroundThread =
new Thread(new PropertiesFileWatcher(watchService), "PropertiesFileWatcher thread");
backgroundThread.setDaemon(true);
backgroundThread.start();
LOG.info("Started background thread");
}
Path pathToConfigFile = configFile.toPath();
Path watchedDir = pathToConfigFile.getParent();
WatchKey key =
watchedDir.register(
watchService,
StandardWatchEventKinds.ENTRY_MODIFY,
StandardWatchEventKinds.ENTRY_DELETE,
StandardWatchEventKinds.ENTRY_CREATE);
// Add check to see if we are already watching this dir/file.
watchKeys.put(key, watchedDir);
LOG.info("Added new watch for properties file " + configFile);
metaDataMap.put(configFile, this);
LOG.info(
String.format(
"Currently watching %d file%s",
metaDataMap.size(), (metaDataMap.size() == 1 ? "" : "s")));
}
}
/** Simple test of each of the standard events */
static void testEvents(Path dir) throws IOException {
System.out.println("-- Standard Events --");
FileSystem fs = FileSystems.getDefault();
Path name = fs.getPath("foo");
try (WatchService watcher = fs.newWatchService()) {
// --- ENTRY_CREATE ---
// register for event
System.out.format("register %s for ENTRY_CREATE\n", dir);
WatchKey myKey = dir.register(watcher, new WatchEvent.Kind<?>[] {ENTRY_CREATE});
checkKey(myKey, dir);
// create file
Path file = dir.resolve("foo");
System.out.format("create %s\n", file);
Files.createFile(file);
// remove key and check that we got the ENTRY_CREATE event
takeExpectedKey(watcher, myKey);
checkExpectedEvent(myKey.pollEvents(), StandardWatchEventKinds.ENTRY_CREATE, name);
System.out.println("reset key");
if (!myKey.reset()) throw new RuntimeException("key has been cancalled");
System.out.println("OKAY");
// --- ENTRY_DELETE ---
System.out.format("register %s for ENTRY_DELETE\n", dir);
WatchKey deleteKey = dir.register(watcher, new WatchEvent.Kind<?>[] {ENTRY_DELETE});
if (deleteKey != myKey) throw new RuntimeException("register did not return existing key");
checkKey(deleteKey, dir);
System.out.format("delete %s\n", file);
Files.delete(file);
takeExpectedKey(watcher, myKey);
checkExpectedEvent(myKey.pollEvents(), StandardWatchEventKinds.ENTRY_DELETE, name);
System.out.println("reset key");
if (!myKey.reset()) throw new RuntimeException("key has been cancalled");
System.out.println("OKAY");
// create the file for the next test
Files.createFile(file);
// --- ENTRY_MODIFY ---
System.out.format("register %s for ENTRY_MODIFY\n", dir);
WatchKey newKey = dir.register(watcher, new WatchEvent.Kind<?>[] {ENTRY_MODIFY});
if (newKey != myKey) throw new RuntimeException("register did not return existing key");
checkKey(newKey, dir);
System.out.format("update: %s\n", file);
try (OutputStream out = Files.newOutputStream(file, StandardOpenOption.APPEND)) {
out.write("I am a small file".getBytes("UTF-8"));
}
// remove key and check that we got the ENTRY_MODIFY event
takeExpectedKey(watcher, myKey);
checkExpectedEvent(myKey.pollEvents(), StandardWatchEventKinds.ENTRY_MODIFY, name);
System.out.println("OKAY");
// done
Files.delete(file);
}
}
/**
* Test that directory can be registered with more than one watch service and that events don't
* interfere with each other
*/
static void testTwoWatchers(Path dir) throws IOException {
System.out.println("-- Two watchers test --");
FileSystem fs = FileSystems.getDefault();
WatchService watcher1 = fs.newWatchService();
WatchService watcher2 = fs.newWatchService();
try {
Path name1 = fs.getPath("gus1");
Path name2 = fs.getPath("gus2");
// create gus1
Path file1 = dir.resolve(name1);
System.out.format("create %s\n", file1);
Files.createFile(file1);
// register with both watch services (different events)
System.out.println("register for different events");
WatchKey key1 = dir.register(watcher1, new WatchEvent.Kind<?>[] {ENTRY_CREATE});
WatchKey key2 = dir.register(watcher2, new WatchEvent.Kind<?>[] {ENTRY_DELETE});
if (key1 == key2) throw new RuntimeException("keys should be different");
// create gus2
Path file2 = dir.resolve(name2);
System.out.format("create %s\n", file2);
Files.createFile(file2);
// check that key1 got ENTRY_CREATE
takeExpectedKey(watcher1, key1);
checkExpectedEvent(key1.pollEvents(), StandardWatchEventKinds.ENTRY_CREATE, name2);
// check that key2 got zero events
WatchKey key = watcher2.poll();
if (key != null) throw new RuntimeException("key not expected");
// delete gus1
Files.delete(file1);
// check that key2 got ENTRY_DELETE
takeExpectedKey(watcher2, key2);
checkExpectedEvent(key2.pollEvents(), StandardWatchEventKinds.ENTRY_DELETE, name1);
// check that key1 got zero events
key = watcher1.poll();
if (key != null) throw new RuntimeException("key not expected");
// reset for next test
key1.reset();
key2.reset();
// change registration with watcher2 so that they are both
// registered for the same event
System.out.println("register for same event");
key2 = dir.register(watcher2, new WatchEvent.Kind<?>[] {ENTRY_CREATE});
// create file and key2 should be queued
System.out.format("create %s\n", file1);
Files.createFile(file1);
takeExpectedKey(watcher2, key2);
checkExpectedEvent(key2.pollEvents(), StandardWatchEventKinds.ENTRY_CREATE, name1);
System.out.println("OKAY");
} finally {
watcher2.close();
watcher1.close();
}
}