ExclusiveMarking enum and checkExclusiveMarking method is very confusing

@Override
  public ExclusiveMarking checkExclusiveMarking(String collectionName, ZkNodeProps message) {
    // CLUSTERSTATUS is always mutually exclusive
    //TODO deprecated remove this check .
    if(CLUSTERSTATUS.isEqual(message.getStr(Overseer.QUEUE_OPERATION)))
      return ExclusiveMarking.EXCLUSIVE;

    synchronized (collectionWip) {
      if(collectionWip.contains(collectionName))
        return ExclusiveMarking.NONEXCLUSIVE;
    }

    return ExclusiveMarking.NOTDETERMINED;
  }