Package name.pachler.nio.file

Class WatchService

  • All Implemented Interfaces:
    java.io.Closeable, java.lang.AutoCloseable
    Direct Known Subclasses:
    PathWatchService
    public abstract class WatchService
extends java.lang.Object
implements java.io.Closeable
    A service that provides monitoring for Watchables, reporting changes on these objects (in the case of jpathwatch, these are Path instances).

    To utilise file monitoring, a program needs to acquire a watch service first, like this:
    WatchService ws = FileSystems.getDefault().newWatchService();

    A path needs to be constructed for the directory to be watched, by simply using the Paths class:
    // assuming we want to watch the '/tmp' directory on a Unix system. Path path = Paths.get("/tmp");

    We can now register the path with the watch service. In this case, we want to watch for files created under the /tmp directory, so we register using Path.register(name.pachler.nio.file.WatchService, name.pachler.nio.file.WatchEvent.Kind<?>...) with the StandardWatchEventKind.ENTRY_CREATE event kind and no modifiers, like this:
    WatchKey key = path.register(ws, ENTRY_CREATE);

    Note that we receive a WatchKey now, which represents the registration of our path with the watch service. The key is also used subsequently to retreive events. We'll now wait for an event to occur, like this:
    // this will block until an event has occurred, or the WatchService is closed. WatchKey k = ws.take();

    • Constructor Summary

      Constructors 
      Modifier Constructor Description
      protected WatchService()  

    • Method Summary

      All Methods Instance Methods Abstract Methods 
      Modifier and Type Method Description
      abstract void close()  
      abstract WatchKey poll()  
      abstract WatchKey poll​(long timeout, java.util.concurrent.TimeUnit unit)  
      abstract WatchKey take()  

      • Methods inherited from class java.lang.Object

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