code: @Override
      public StringBuffer format(double number,
                                 StringBuffer toAppendTo,
                                 FieldPosition ignore) {
          // this is one of the inherited format() methods.  Since it doesn't
          // have a way to select the rule set to use, it just uses the
          // default one
          // Note, the BigInteger/BigDecimal methods below currently go through this.
          if (toAppendTo.length() == 0) {
              toAppendTo.append(adjustForContext(format(number, defaultRuleSet)));
          } else {
              // appending to other text, don't capitalize
              toAppendTo.append(format(number, defaultRuleSet));
          }
          return toAppendTo;
      }
docs: Formats the specified number using the formatter's default rule set.
  (The default rule set is the last public rule set defined in the description.)
  @param number The number to format.
  @param toAppendTo A StringBuffer that the result should be appended to.
  @param ignore This function doesn't examine or update the field position.
  @return toAppendTo