Method atLongitude

base/src/main/java/net/time4j/tz/ZonalOffset.java:202–229

(BigDecimal longitude)

     * @throws  IllegalArgumentException if range check fails
     */
    public static ZonalOffset atLongitude(BigDecimal longitude) {

        if (
            (longitude.compareTo(DECIMAL_POS_180) > 0)
            || (longitude.compareTo(DECIMAL_NEG_180) < 0)
        ) {
            throw new IllegalArgumentException("Out of range: " + longitude);
        }

        BigDecimal offset = longitude.multiply(DECIMAL_240);
        BigDecimal integral = offset.setScale(0, RoundingMode.DOWN);
        BigDecimal delta = offset.subtract(integral);
        BigDecimal decimal = delta.setScale(9, RoundingMode.HALF_UP).multiply(MRD);

        int total = integral.intValueExact();
        int fraction = decimal.intValueExact();

        if (fraction == 0) {
            return ZonalOffset.ofTotalSeconds(total);
        } else if (fraction == 1_000_000_000) {
            return ZonalOffset.ofTotalSeconds(total + 1);
        } else if (fraction == -1_000_000_000) {
            return ZonalOffset.ofTotalSeconds(total - 1);
        } else {
            return new ZonalOffset(total, fraction);
        }

    }

    /**
     * <p>Creates a new shift based on a geographical longitude. </p>