@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;
}
@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 user has provided enough money to purchase a product.
*
* @param pence Money provided by the user.
* @param p The Product selected by the user.
* @return True if there is enough money. False otherwise.
*/
private boolean enoughMoneyProvided(int pence, Product p) {
return pence - p.getProductPrice() >= 0;
}