docs: public String getString() 
      {
          String string = super.getString();  // By default, get the data as-is
          if (this.getField() instanceof NumberField)
          {
              double dValue = this.getField().getValue();
              if (m_bDebit)
              {
                  if (dValue < 0)
                      string = Constants.BLANK; // For debit/negative, return a null
              }
              else
              {   // Credit
                  if (dValue >= 0)
                      string = Constants.BLANK; // For credit/positive, return a null
                  else
                      string = ((NumberField)this.getField()).binaryToString(new Double(-dValue));  // Positive representation
              }
          }
          return string;
      }