@Override public AbstractDate plus(long amountToAdd, TemporalUnit unit) { if (unit instanceof ChronoUnit) { ChronoUnit f = (ChronoUnit) unit; switch (f) { case DAYS: return plusDays(amountToAdd); case WEEKS: return plusWeeks(amountToAdd); case MONTHS: return plusMonths(amountToAdd); case YEARS: return plusYears(amountToAdd); case DECADES: return plusYears(Math.multiplyExact(amountToAdd, 10)); case CENTURIES: return plusYears(Math.multiplyExact(amountToAdd, 100)); case MILLENNIA: return plusYears(Math.multiplyExact(amountToAdd, 1000)); case ERAS: return with(ERA, Math.addExact(getLong(ERA), amountToAdd)); default: break; } throw new UnsupportedTemporalTypeException("Unsupported unit: " + unit); } return unit.addTo(this, amountToAdd); }