code: private void handleMissingFields()
      {
          MissingFieldHandler missingFieldHandler = reader.getMissingFieldHandler();
          if (missingFieldHandler != null)
          {
              for (Missingfields mf : missingFields)
              {
                  missingFieldHandler.fieldMissing(mf.target, mf.fieldName, mf.value);
              }
          }//else no handler so ignore.
      }
docs: calls the missing field handler if any for each recorded missing field.