/**
* Obtains a {@code PeriodFields} from an amount and unit, by extending any fractional remainder
* onto smaller units.
*
* <p>The parameters represent the two parts of a phrase like 'one-and-a-half Hours'. The
* fractional parts will be distributed into the smaller units, and rounded down when no smaller
* units exist. If the {@code fractionalAmount} is negative, the amount of the biggest unit will
* be negative, the rest will be positive.
*
* @param fractionalAmount the amount of create with, positive or negative
* @param unit the period unit, not null
* @return the {@code PeriodFields} instance, not null
*/
public static PeriodFields of(double fractionalAmount, PeriodUnit unit) {
checkNotNull(unit, "PeriodUnit must not be null");
PeriodUnit currentUnit = unit;
double fudge = 0.000000000000001d;
TreeMap<PeriodUnit, PeriodField> internalMap = createMap();
do {
long floor = (long) Math.floor(fractionalAmount + fudge);
if (floor != 0) {
internalMap.put(currentUnit, PeriodField.of(floor, currentUnit));
}
double remainder = fractionalAmount - floor; // will be positive
PeriodField nextEquivalent = currentUnit.getNextEquivalentPeriod();
if (nextEquivalent != null) {
currentUnit = nextEquivalent.getUnit();
fractionalAmount = remainder * nextEquivalent.getAmount();
fudge *= nextEquivalent.getAmount();
} else {
// No smaller units exist, we're done
currentUnit = null;
}
} while (currentUnit != null && Math.abs(fractionalAmount) > fudge);
if (internalMap.isEmpty()) {
return of(0L, unit);
} else {
return create(internalMap);
}
}
