code: public VALUEFROM decodeFromGettable(GettableData gettableData) {
          if (gettableData.isNull(NamingHelper.maybeQuote(getColumnForSelect())) && !isOptional()) return null;
          return decodeFromGettableInternal(gettableData);
      }
docs: Decode the given GettableData (Row, UDTValue, ...) to Java value value using Achilles codec system
  @param gettableData
  @return