@Override
public Collection<Coin> getChangeFor(int pence, Product p)
throws NotEnoughChangeException, NotEnoughMoneyException {
changeInProgress.clear();
int difference = pence - p.getProductPrice();
loadConfig();
if (enoughMoneyProvided(pence, p)) {
if (enoughChange(difference)) {
for (Coin coin : Coin.values()) {
if (isCoinTypeNeeded(coin, difference - getCurrentChange())) {
supplyThisCoinType(coin, difference - getCurrentChange(), true);
}
}
if (getCurrentChange() != difference)
throw new NotEnoughChangeException("The machine has run out of change.");
updateConfig();
} else {
throw new NotEnoughChangeException("The machine has run out of change.");
}
} else {
throw new NotEnoughMoneyException("You have not provided enough money.");
}
return changeInProgress;
}
/**
* Returns an integer indicating the maximum number of coins available of a specific type.
*
* @param difference Amount between the money provided and the product price.
* @param coin Current coin in the Map<Coin,Integer>
* @param changeLimits Indicated whether there is an unlimited supply of change in the machine or
* not.
* @return Integer indicating the maximum amount of coins available for distribution.
*/
private int getCap(int difference, Coin coin, boolean changeLimits) {
int capExact = difference / coin.getValueAsInt();
if (changeLimits) {
int capMachine = availableChangeMachine.get(coin);
if (capExact >= capMachine) {
return capMachine;
}
}
return capExact;
}
@Override
public Collection<Coin> getOptimalChangeFor(int pence, Product p) throws NotEnoughMoneyException {
changeInProgress.clear();
int difference = pence - p.getProductPrice();
if (enoughMoneyProvided(pence, p)) {
for (Coin coin : Coin.values()) {
if (isCoinTypeNeeded(coin, difference - getCurrentChange())) {
supplyThisCoinType(coin, difference - getCurrentChange(), false);
}
}
} else {
throw new NotEnoughMoneyException(
"You have not provided enough money.\n"
+ "Remeber that 10 pounds need to be entered as 1000 (one thousand pennies), for example.");
}
return changeInProgress;
}
/**
* Checks if the current coin in the Map<Coin,Integer> needs to be added to the changeInProgress.
*
* @param coin Current coin in the Map<Coin,Integer>
* @param difference Amount between the money provided and the product price.
* @return True if the current coin fits the criteria for the return change.
*/
private boolean isCoinTypeNeeded(Coin coin, int difference) {
return difference / coin.getValueAsInt() > 0;
}