@Nullable
 public TaskDescriptor<IndexCommandResult> getIndexTask(long taskId) {
   TaskDescriptor<IndexCommandResult> indexingTask = null;
   final TaskDescriptor<?> task = taskManager.getTask(taskId);
   if (task != null && task.getTaskContext() instanceof IndexTaskContext) {
     indexingTask = (TaskDescriptor<IndexCommandResult>) task;
   }
   return indexingTask;
 }