public class Withdrawal extends Transaction
{
    private int amount;
    private Keypad keypad;
    private CashDispenser cashDispenser;

    private final static int CANCELED = 6;

    public Withdrawal(int userAccountNumber, Screen atmScreen,
        BankDatabase atmBankDatabase, Keypad atmKeypad,
        CashDispenser atmCashDispenser)
    {
        super(userAccountNumber, atmScreen, atmBankDatabase);

        keypad = atmKeypad;
        cashDispenser = atmCashDispenser;
    }

    @Override
    public void execute()
    {
        boolean cashDispensed = false;
        double availableBalance;

        BankDatabase bankDatabase = getBankDatabase();
        Screen screen = getScreen();

        do
        {
            amount = displayMenuOfAmounts();

            if(amount!= CANCELED)
            {
                availableBalance = bankDatabase.getAvailableBalance(getAccountNumber());

                if(amount <= availableBalance)
                {
                    if(cashDispenser.isSufficientCashAvailable(amount))
                    {
                        bankDatabase.debit(getAccountNumber(), amount);

                        cashDispenser.dispenseCash(amount);
                        cashDispensed = true;

                        screen.displayMessageLine("\nYour cash has been"
                        + " dispensed. Please take your cash now.");
                    }
                    else
                        screen.displayMessageLine(
                        "\nInsufficient cash available in the ATM." +
                        "\n\nPlease choose a smaller amount.");
                }
                else
                {
                    screen.displayMessageLine(
                        "\nInsufficient funds in your account." +
                        "\n\nPlease choose a smaller amount.");
                }
            }
            else
            {
                screen.displayMessageLine("\nCanceling transaction...");
                return;
            }
        } while( !cashDispensed );

    }

    private int displayMenuOfAmounts()
    {
        int userChoice = 0;

        Screen screen = getScreen();

        int[] amounts = {0, 20, 40, 60, 100, 200};

        while(userChoice ==0)
        {
            screen.displayMessageLine("\nWithdrawal Menu:");
            screen.displayMessageLine("1 - $20");
            screen.displayMessageLine("2 - $40");
            screen.displayMessageLine("3 - $60");
            screen.displayMessageLine("4 - $100");
            screen.displayMessageLine("5 - $200");
            screen.displayMessageLine("6 - Cancel transaction");
            screen.displayMessage("\nChoose a withdrawal amount: ");

            int input = keypad.getInput();

            switch(input)
            {
                case 1:
                case 2:
                case 3:
                case 4:
                case 5:
                    userChoice = amounts[input];
                    break;
                case CANCELED:
                    userChoice = CANCELED;
                    break;
                default:
                    screen.displayMessageLine(
                        "\nInvalid selection. Try again.");
            }
        }
        return userChoice;
    }

}