How to use

getObservers

method

in

org.apache.commons.io.monitor.FileAlterationMonitor

/**
 * Test add/remove observers.
 */
@Test
public void testAddRemoveObservers() {
  FileAlterationObserver[] observers = null;
  FileAlterationMonitor monitor = null;
  // Null Observers
  monitor = new FileAlterationMonitor(123, observers);
  assertEquals("Interval", 123, monitor.getInterval());
  assertFalse("Observers[1]", monitor.getObservers().iterator().hasNext());
  // Null Observer
  observers = new FileAlterationObserver[1]; // observer is null
  monitor = new FileAlterationMonitor(456, observers);
  assertFalse("Observers[2]", monitor.getObservers().iterator().hasNext());
  // Null Observer
  monitor.addObserver(null);
  assertFalse("Observers[3]", monitor.getObservers().iterator().hasNext());
  monitor.removeObserver(null);
  // Add Observer
  final FileAlterationObserver observer = new FileAlterationObserver("foo");
  monitor.addObserver(observer);
  final Iterator<FileAlterationObserver> it = monitor.getObservers().iterator();
  assertTrue("Observers[4]", it.hasNext());
  assertEquals("Added", observer, it.next());
  assertFalse("Observers[5]", it.hasNext());
  // Remove Observer
  monitor.removeObserver(observer);
  assertFalse("Observers[6]", monitor.getObservers().iterator().hasNext());
}

/**
 *
 */
private synchronized void syncMonitor() {
  observers.forEach((path, observer)
    -> this.monitor.getObservers().forEach(observer2 -> {
    Path path1 = Paths.get(observer2.getDirectory().toString());
    if (!observers.containsKey(path1)) {
      this.monitor.removeObserver(observer2);
    }
  }));
}

{
   FileAlterationMonitor monitor = new FileAlterationMonitor();
   Iterator<FileAlterationObserver> iterator = monitor.getObservers().iterator();
   FileAlterationObserver last = null;
   while (iterator.hasNext()) {
     last = iterator.next();
   }
   final CountDownLatch cdl = new CountDownLatch(1);
   monitor.removeObserver(last);
   monitor.addObserver(new FileAlterationObserver(last.getDirectory(), last.getFileFilter()) {
     @Override
     public void initialize() throws Exception {
       super.initialize();
       cdl.countDown();
     }
   });
   try {
     // wait until last observer would be initialized
     monitor.start();
     cdl.await();
   } catch (InterruptedException e) {
     e.printStackTrace();
   } catch (Exception e) {
     e.printStackTrace();
   }
 }