private void cancelFilteringTask() {
    if (myFilteringTask != null) {
      synchronized (myFilteringTaskLock) {
        if (myFilteringTask != null) {
          myFilteringTask.cancel();
          myFilteringTask = null;
          myFilteringTaskFuture.cancel(false);
          myFilteringTaskFuture = null;
        }
      }
    }
  }
private void cancelFilteringTask()