public String getTailNode() {
    if (nodes.length <= 0) {
      return "";
    }
    return nodes[nodes.length - 1];
  }
only use this method in following situations: 1. you are sure node is allowed in syntax
convention. 2. you are sure node needs not to be checked.
iotdb-core/node-commons/src/main/java/org/apache/iotdb/commons/path/PartialPath.java