BetterTicketMachine.java

/**
* TicketMachine models a ticket machine that issues
* flat-fare tickets.
* The price of a ticket is specified via the constructor.
* Instances will check to ensure that a user only enters
* sensible amounts of money, and will only print a ticket
* if enough money has been input.
* @author David J. Barnes and Michael Kölling
* @version 2006.03.30
*/
public class BetterTicketMachine
{
// The price of a ticket from this machine.
private int price;
// The amount of money entered by a customer so far.
private int balance;
// The total amount of money collected by this machine.
private int total;
/**
* Create a machine that issues tickets of the given price.
*/
public BetterTicketMachine(int ticketCost)
{
price = ticketCost;
balance = 0;
total = 0;
}
/**
* Return the price of a ticket.
*/
public int getPrice()
{
return price;
}
/**
* Return the amount of money already inserted for the
* next ticket.
*/
public int getBalance()
{
return balance;
}
/**
* Receive an amount of money in cents from a customer.
* Check that the amount is sensible.
*/
public void insertMoney(int amount)
{
if(amount > 0) {
balance = balance + amount;
}
else {
System.out.println("Use a positive amount: " +
amount);
}
}
/**
* Print a ticket if enough money has been inserted, and
* reduce the current balance by the ticket price. Print
* an error message if more money is required.
*/
public void printTicket(){
    int amountLeftToPay = price - balance;
    if(amountLeftToPay <= 0) {
        // Simulate the printing of a ticket.
            System.out.println("##################");
            System.out.println("# The BlueJ Line");
            System.out.println("# Ticket");
            System.out.println("# " + price + " cents.");
            System.out.println("##################");
            System.out.println();
            // Update the total collected with the price.
            total = total + price;
            // Reduce the balance by the price.
            balance = balance - price;
    } else {
        System.out.println("You must insert at least: " +
(price - balance) + " MORE cent(s).");
    }
}

public int emptyMachine(){
    int temp = total;
    total = 0;
    return temp;
}

/**
* Return the money in the balance.
* The balance is cleared.
*/
public int refundBalance()
{
int amountToRefund;
amountToRefund = balance;
balance = 0;
return amountToRefund;
}
}