FP_VendingMachine_VM

public class Vending_Machine
{
    private boolean userAuthenticated;
    private int currentCardNumber;
    private Screen screen;
    private Keypad keypad;
    private ItemDispenser itemDispenser;
    private BankDatabase bankDatabase;

    private static final int AQUA = 1;
    private static final int TEH_PUCUK = 2;
    private static final int POCARI_SWEAT = 3;
    private static final int EXIT = 0;

    public Vending_Machine()
    {

        userAuthenticated = false;
        currentCardNumber = 0;
        screen = new Screen();
        keypad = new Keypad();
        itemDispenser = new ItemDispenser();
        bankDatabase = new BankDatabase();
    }

    public void run()
    {
        while ( true )
        {
            screen.displayMessageLine( "\nSelamat Datang!" );
            performTransactions();
            userAuthenticated = false;
            currentCardNumber = 0;
            screen.displayMessageLine( "\nTerima Kasih! Selamat Tinggal!" );
        }

    }

    private void performTransactions()
    {
        Transaction currentTransaction = null;
        boolean userExited = false;

        int mainMenuSelection = displayMenuOfItem();

        switch(mainMenuSelection)
        {
           case AQUA:
           case TEH_PUCUK:
           case POCARI_SWEAT:
                while ( !userAuthenticated )
                {
                    authenticateUser();
                    userAuthenticated = true;
                }
                currentTransaction =
                createTransaction( mainMenuSelection );
                currentTransaction.execute();
                break;
           case EXIT:
                screen.displayMessageLine( "\nMembatalkan Transaksi. . .");
                break;
           default:
                screen.displayMessageLine(
                "\nMasukkan angka yang sesuai. Coba lagi." );
                break;
        }
    }

    private int displayMenuOfItem()
    {
        screen.displayMessageLine( "\nMenu Utama:" );
        screen.displayMessageLine( "1 - AQUA - Rp. 2500" );
        screen.displayMessageLine( "2 - TEH PUCUK - Rp. 4000" );
        screen.displayMessageLine( "3 - POCARI SWEAT - Rp. 6000" );
        screen.displayMessageLine( "0 - Keluar\n" );
        screen.displayMessage( "Masukkan Pilihan: " );
        return keypad.getInput();
    }

    private void authenticateUser()
    {
        screen.displayMessage( "\nTaruh kartu Mandiri E-Money disini : " );
        int cardNumber = keypad.getInput();

        userAuthenticated = bankDatabase.authenticateUser(cardNumber);

        if ( userAuthenticated )
        {
            currentCardNumber = cardNumber;
        }

        else
            screen.displayMessageLine(
                "Mohon maaf kartu e-money anda tidak dapat teridentifikasi. Silahkan coba lagi." );
    }

    private Transaction createTransaction( int type )
    {
        Transaction temp = null;
        switch ( type )
        {
            case AQUA:
            case TEH_PUCUK:
            case POCARI_SWEAT:
                temp = new Pembelian( currentCardNumber, screen, bankDatabase, keypad, itemDispenser, type );
                break;
        }
        return temp;
    }
}