code: public MoneyAmountStyle withGroupingStyle(GroupingStyle groupingStyle) {
          MoneyFormatter.checkNotNull(groupingStyle, "groupingStyle");
          if (this.groupingStyle == groupingStyle) {
              return this;
          }
          return new MoneyAmountStyle(
                  zeroCharacter,
                  positiveCharacter, negativeCharacter,
                  decimalPointCharacter, groupingStyle,
                  groupingCharacter, groupingSize, extendedGroupingSize, forceDecimalPoint, absValue);
      }
docs: Returns a copy of this style with the specified grouping setting.
  
  @param groupingStyle  the grouping style, not null
  @return the new instance for chaining, never null