scope jdk_watchService_start.

static new Flag #started;
static new MultiMap<WatchKey, O> #listeners;

static WatchService jdk_watchService_start() {
  final WatchService service = jdk_defaultWatchService();
  if (started.raise()) thread "Watch Service" {
    while licensed { 
      WatchKey key = service.poll(10, TimeUnit.SECONDS);
      if (key != null) {
        Path dir = cast key.watchable();
        for (WatchEvent<?> event : key.pollEvents()) pcall {
          final Path changed = (Path) event.context();
          File full = newFile(dir.toFile(), changed.toFile().getPath());
          //print("WatchService Changed: " + full + ", " + event.kind());
          pcallFAll(listeners.get(key), full);
        }
        key.reset();
      }
    }
  }
  ret service;
}

end scope