org.imca_cat.pollingwatchservice

Interface PathWatchService

All Superinterfaces:

AutoCloseable, Closeable, WatchService

All Known Implementing Classes:

EventingWatchService, PollingWatchService

public interface PathWatchService
extends WatchService

A service for watching Path objects for changes.

A PathWatchService is similar to a WatchService except that a PathWatchService must be started, it only watches Path instances (not Watchable instances), and instead of calling one of the register methods on a Watchable, we call one of the register methods on this interface.

To use this service, create an instance, register directories to watch via the register methods, and start it via the start method. Registering directories to watch can be performed before and after starting the service. Retrieve changes via the poll or take methods, and close the service when done via the close method.

Example:

     PathWatchService s = newPathWatchService();
     s.register(FileSystems.getDefault().getPath("/home/luke"),
         StandardWatchEventKinds.ENTRY_CREATE,
         StandardWatchEventKinds.ENTRY_DELETE,
         StandardWatchEventKinds.ENTRY_MODIFY);
     s.start();
     for (;;) {
       WatchKey k = s.take();
       ...
     }
 

Method Summary

Modifier and Type	Method and Description
WatchKey	register(Path dir, WatchEvent.Kind<?>... kinds) Registers the specified directory, using the specified WatchEvent kinds and no WatchEvent modifiers, with this watch service.
WatchKey	register(Path dir, WatchEvent.Kind<?>[] kinds, WatchEvent.Modifier... modifiers) Registers the specified directory, using the specified WatchEvent kinds and modifiers, with this watch service.
void	start() Starts this service.

Methods inherited from interface WatchService

close, poll, poll, take

Method Detail

start

void start()

Starts this service.

Throws:

ClosedWatchServiceException - if closed

IllegalStateException - if already started

register

WatchKey register(Path dir,
                  WatchEvent.Kind<?>... kinds)
           throws IOException

Registers the specified directory, using the specified WatchEvent kinds and no WatchEvent modifiers, with this watch service.

This method is intended to be similar in behavior to Path.register(WatchService, WatchEvent.Kind[]).

Parameters:

dir - directory to watch; must not be a symbolic link

kinds - events to register for

Throws:

ClosedWatchServiceException - if this watch service is closed

NotDirectoryException - if dir is not a directory

IOException - if an I/O error occurs

register

WatchKey register(Path dir,
                  WatchEvent.Kind<?>[] kinds,
                  WatchEvent.Modifier... modifiers)
           throws IOException

Registers the specified directory, using the specified WatchEvent kinds and modifiers, with this watch service.

This method is intended to be similar in behavior to Path.register(WatchService, WatchEvent.Kind[], WatchEvent.Modifier[]) .

Parameters:

dir - directory to watch; must not be a symbolic link

kinds - events to register for

modifiers - modifiers modifying how dir is registered

Throws:

ClosedWatchServiceException - if this watch service is closed

NotDirectoryException - if dir is not a directory

IOException - if an I/O error occurs