Class BigDecimalMath

    • Method Detail

      • roundToDouble

        public static double roundToDouble​(BigDecimal x,
                                           RoundingMode mode)
        Returns x, rounded to a double with the specified rounding mode. If x is precisely representable as a double, its double value will be returned; otherwise, the rounding will choose between the two nearest representable values with mode.

        For the case of RoundingMode.HALF_DOWN, HALF_UP, and HALF_EVEN, infinite double values are considered infinitely far away. For example, 2^2000 is not representable as a double, but roundToDouble(BigDecimal.valueOf(2).pow(2000), HALF_UP) will return Double.MAX_VALUE, not Double.POSITIVE_INFINITY.

        For the case of RoundingMode.HALF_EVEN, this implementation uses the IEEE 754 default rounding mode: if the two nearest representable values are equally near, the one with the least significant bit zero is chosen. (In such cases, both of the nearest representable values are even integers; this method returns the one that is a multiple of a greater power of two.)

        ArithmeticException - if mode is RoundingMode.UNNECESSARY and x is not precisely representable as a double