public static TypeInfo convert(RelDataType rType) {
    if (rType.isStruct()) {
      return convertStructType(rType);
    } else if (rType.getComponentType() != null) {
      return convertListType(rType);
    } else if (rType.getKeyType() != null) {
      return convertMapType(rType);
    } else {
      return convertPrimitiveType(rType);
    }
  }
******************** Convert Hive Types To Calcite Types **********************
ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/translator/TypeConverter.java