tdcommon/src/main/java/thredds/server/catalog/tracker/CatalogWatcher.java
public void processEvents() {
    if (!enable) return;

    for (; ; ) {

      // wait for key to be signalled
      WatchKey key;
      try {
        key = watcher.take();
      } catch (InterruptedException x) {
        return;
      }

      Path dir = keys.get(key);
      if (dir == null) {
        System.err.println("WatchKey not recognized!!");
        continue;
      }

      for (WatchEvent<?> event : key.pollEvents()) {
        WatchEvent.Kind kind = event.kind();

        // TBD - provide example of how OVERFLOW event is handled
        if (kind == OVERFLOW) {
          continue;
        }

        // Context for directory entry event is the file name of entry
        WatchEvent<Path> ev = cast(event);
        Path name = ev.context();
        Path child = dir.resolve(name);

        // print out event
        System.out.format("%s: %s%n", event.kind().name(), child);

        // if directory is created, and watching recursively, then
        // register it and its sub-directories
        if (recursive && (kind == ENTRY_CREATE)) {
          try {
            if (Files.isDirectory(child, NOFOLLOW_LINKS)) {
              registerAll(child);
            }
          } catch (IOException x) {
            // ignore to keep sample readbale
          }
        }
      }

      // reset key and remove from set if directory no longer accessible
      boolean valid = key.reset();
      if (!valid) {
        keys.remove(key);

        // all directories are inaccessible
        if (keys.isEmpty()) {
          break;
        }
      }
    }
  }
public void processEvents() {
    if (!enable) return;

    for (; ; ) {

      // wait for key to be signalled
      WatchKey key;
      try {
        key = watcher.take();
      } catch (InterruptedException x) {
        return;
      }

      Path dir = keys.get(key);
      if (dir == null) {
        System.err.println("WatchKey not recognized!!");
        continue;
      }

      for (WatchEvent<?> event : key.pollEvents()) {
        WatchEvent.Kind kind = event.kind();

        // TBD - provide example of how OVERFLOW event is handled
        if (kind == OVERFLOW) {
          continue;
        }

        // Context for directory entry event is the file name of entry
        WatchEvent<Path> ev = cast(event);
        Path name = ev.context();
        Path child = dir.resolve(name);

        // print out event
        System.out.format("%s: %s%n", event.kind().name(), child);

        // if directory is created, and watching recursively, then
        // register it and its sub-directories
        if (recursive && (kind == ENTRY_CREATE)) {
          try {
            if (Files.isDirectory(child, NOFOLLOW_LINKS)) {
              registerAll(child);
            }
          } catch (IOException x) {
            // ignore to keep sample readbale
          }
        }
      }

      // reset key and remove from set if directory no longer accessible
      boolean valid = key.reset();
      if (!valid) {
        keys.remove(key);

        // all directories are inaccessible
        if (keys.isEmpty()) {
          break;
        }
      }
    }
  }
Process all events for keys queued to the watcher