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// ATM.java

// Represents an automated teller machine

public class ATM {

private boolean userAuthenticated; // whether user is authenticated

private int currentAccountNumber; // current user's account number

private Screen screen; // ATM's screen

private Keypad keypad; // ATM's keypad

private CashDispenser cashDispenser; // ATM's cash dispenser

private DepositSlot depositSlot; // ATM's deposit slot

private BankDatabase bankDatabase; // account information database

// constants corresponding to main menu options

private static final int BALANCE_INQUIRY = 1;

private static final int WITHDRAWAL = 2;

private static final int DEPOSIT = 3;

private static final int EXIT = 4;

// no-argument ATM constructor initializes instance variables

public ATM() {

userAuthenticated = false; // user is not authenticated to start

currentAccountNumber = 0; // no current account number to start

screen = new Screen(); // create screen

keypad = new Keypad(); // create keypad

cashDispenser = new CashDispenser(); // create cash dispenser

depositSlot = new DepositSlot(); // create deposit slot

bankDatabase = new BankDatabase(); // create acct info database

}

// start ATM

public void run() {

// welcome and authenticate user; perform transactions

while (true) {

// loop while user is not yet authenticated

while (!userAuthenticated) {

screen.displayMessageLine("\nWelcome!");

authenticateUser(); // authenticate user

}

performTransactions(); // user is now authenticated

userAuthenticated = false; // reset before next ATM session

currentAccountNumber = 0; // reset before next ATM session

screen.displayMessageLine("\nThank you! Goodbye!");

}

}

// attempts to authenticate user against database

private void authenticateUser() {

screen.displayMessage("\nPlease enter your account number: ");

int accountNumber = keypad.getInput(); // input account number

screen.displayMessage("\nEnter your PIN: "); // prompt for PIN

int pin = keypad.getInput(); // input PIN

// set userAuthenticated to boolean value returned by database

userAuthenticated =

bankDatabase.authenticateUser(accountNumber, pin);

// check whether authentication succeeded

if (userAuthenticated) {

currentAccountNumber = accountNumber; // save user's account #

}

else {

screen.displayMessageLine(

"Invalid account number or PIN. Please try again.");

}

}

// display the main menu and perform transactions

private void performTransactions() {

// local variable to store transaction currently being processed

Transaction currentTransaction = null;

boolean userExited = false; // user has not chosen to exit

// loop while user has not chosen option to exit system

while (!userExited) {

// show main menu and get user selection

int mainMenuSelection = displayMainMenu();

// decide how to proceed based on user's menu selection

switch (mainMenuSelection) {

// user chose to perform one of three transaction types

case BALANCE_INQUIRY:

case WITHDRAWAL:

case DEPOSIT:

// initialize as new object of chosen type

currentTransaction =

createTransaction(mainMenuSelection);

currentTransaction.execute(); // execute transaction

break;

case EXIT: // user chose to terminate session

screen.displayMessageLine("\nExiting the system...");

userExited = true; // this ATM session should end

break;

default: // user did not enter an integer from 1-4

screen.displayMessageLine(

"\nYou did not enter a valid selection. Try again.");

break;

}

}

}

// display the main menu and return an input selection

private int displayMainMenu() {

screen.displayMessageLine("\nMain menu:");

screen.displayMessageLine("1 - View my balance");

screen.displayMessageLine("2 - Withdraw cash");

screen.displayMessageLine("3 - Deposit funds");

screen.displayMessageLine("4 - Exit\n");

screen.displayMessage("Enter a choice: ");

return keypad.getInput(); // return user's selection

}

// return object of specified Transaction subclass

private Transaction createTransaction(int type) {

Transaction temp = null; // temporary Transaction variable

// determine which type of Transaction to create

switch (type) {

case BALANCE_INQUIRY: // create new BalanceInquiry transaction

temp = new BalanceInquiry(

currentAccountNumber, screen, bankDatabase);

break;

case WITHDRAWAL: // create new Withdrawal transaction

temp = new Withdrawal(currentAccountNumber, screen,

bankDatabase, keypad, cashDispenser);

break;

case DEPOSIT: // create new Deposit transaction

temp = new Deposit(currentAccountNumber, screen,

bankDatabase, keypad, depositSlot);

break;

}

return temp; // return the newly created object

}

}

/**************************************************************************

* (C) Copyright 1992-2018 by Deitel & Associates, Inc. and *

* Pearson Education, Inc. All Rights Reserved. *

* *

* DISCLAIMER: The authors and publisher of this book have used their *

* best efforts in preparing the book. These efforts include the *

* development, research, and testing of the theories and programs *

* to determine their effectiveness. The authors and publisher make *

* no warranty of any kind, expressed or implied, with regard to these *

* programs or to the documentation contained in these books. The authors *

* and publisher shall not be liable in any event for incidental or *

* consequential damages in connection with, or arising out of, the *

* furnishing, performance, or use of these programs. *

*************************************************************************/