Questions about AggType

[Sea]

Hi??all:
   I feel a little confused abount AggType, Anyone can explain ? 




public static char getAggType(DataType dataType) {
  switch (dataType) {
    case DECIMAL:
      return CarbonCommonConstants.BIG_DECIMAL_MEASURE;
    case INT:
    case LONG:
      return CarbonCommonConstants.BIG_INT_MEASURE;
    default:
      return CarbonCommonConstants.SUM_COUNT_VALUE_MEASURE;
  }
}