Package org.forgerock.util

Class DirectoryWatcher

java.lang.Object

org.forgerock.util.DirectoryWatcher

public class DirectoryWatcher
extends Object

High-level interface to the WatchService API for detecting filesystem change events.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
class	DirectoryWatcher.ChangeListener	A change listener for a single directory that can be used to register notification callbacks and to cancel observing this directory.

Constructor Summary

Constructors

Constructor	Description
DirectoryWatcher(ScheduledExecutorService scheduledExecutorService, WatchEvent.Modifier... modifiers)	Initializes the directory watcher.

Method Summary

Modifier and Type	Method	Description
void	shutdown()	Shuts down the directory watcher, cancelling all registered watch tasks and closing the underlying watch service.
final DirectoryWatcher.ChangeListener	watch(Path directory, WatchEvent.Kind<Path>... eventKinds)	Registers a directory to be watched for change notifications.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

DirectoryWatcher

public DirectoryWatcher(ScheduledExecutorService scheduledExecutorService,
 WatchEvent.Modifier... modifiers)
                 throws IOException

Initializes the directory watcher. The watcher will use the given executor service to execute a periodic task polling for filesystem changes. The watch service from the default filesystem will be used to wait for events.

Parameters:

scheduledExecutorService - the scheduled executor service (never null). A periodic task will be added that polls for filesystem events every second.

modifiers - how urgently events should be delivered. A higher value will result in more frequent polling of the filesystem in some implementations. The allowed values are JVM specific. On Hotspot use com.sun.nio.file.SensitivityWatchEventModifier. Leave unspecified to use the default sensitivity. Other modifiers may also be allowed depending on the platform.

Throws:

IOException - if an I/O error occurs when trying to construct the watch service.

Method Details

watch

@SafeVarargs
public final DirectoryWatcher.ChangeListener watch(Path directory,
 WatchEvent.Kind<Path>... eventKinds)
                                            throws IOException

Registers a directory to be watched for change notifications.

Parameters:

directory - the directory to watch.

eventKinds - the kinds of events to watch. See StandardWatchEventKinds for values.

Returns:

a change listener that can be used to add callbacks.

Throws:

IOException - if an I/O error prevents the directory being watched.

IllegalStateException - if the watch service has already been shut down.

shutdown

public void shutdown()

Shuts down the directory watcher, cancelling all registered watch tasks and closing the underlying watch service.