public Integer compare(ValueStore<V> other) {
if (other.moneySystem != moneySystem) {
return null;
}
V val = moneySystem.subtract(getValue(), other.getValue());
return (moneySystem.isValueNothing(val) ? 0 : (moneySystem.isValueDeficit(val) ? -1 : 1));
}
public boolean equals(ValueStore<V> other) {
return (other.moneySystem == moneySystem
&& moneySystem.isValueNothing(moneySystem.subtract(getValue(), other.getValue())));
}
public boolean subtractValue(V value) {
return setValue(moneySystem.subtract(getValue(), value));
}
