public static String prefixString(int indentFlag) {
    StringBuilder sb = new StringBuilder();
    for (int index = 0; index < indentFlag; index++) {
      sb.append("  ");
    }
    return sb.toString();
  }
@param indentFlag
         help to generate correct indent
@return
common/src/java/org/apache/hadoop/hive/common/jsonexplain/DagJsonParser.java