code: public static MonetaryOperator rounding(RoundingMode roundingMode, int scale) {
  		return new RoundingMonetaryAmountOperator(Objects.requireNonNull(roundingMode), scale);
  	}
docs: Rounding the {@link MonetaryAmount} using {@link CurrencyUnit#getDefaultFractionDigits()}
  and {@link RoundingMode}.
  <p>
  For example, 'EUR 2.3523' will return 'EUR 2.35',
  and 'BHD -1.34534432' will return 'BHD -1.345'.
  <p>
  <pre>
  {@code
  MonetaryAmount money = Money.parse("EUR 2.355432");
  MonetaryAmount result = ConversionOperators.rounding(RoundingMode.HALF_EVEN, 3).apply(money);//EUR 2.352
  }
  </pre>
  @param roundingMode rounding to be used
  @param scale to be used
  @return the major part as {@link MonetaryOperator}