Untuk class diagram dengan attr dan operations, bisa digambarkan sebagai berikut.
Langsung ke bagian source code:
- Class ATM
public class ATM
{
private boolean userAuthenticated;
private int currentAccountNumber;
private Screen screen;
private Keypad keypad;
private CashDispenser cashDispenser;
private DepositSlot depositSlot;
private BankDatabase bankDatabase;
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;
public ATM()
{
userAuthenticated = false;
currentAccountNumber = 0;
screen = new Screen();
keypad = new Keypad();
cashDispenser = new CashDispenser();
depositSlot = new DepositSlot();
bankDatabase = new BankDatabase();
}
public void run()
{
while ( true )
{
while ( !userAuthenticated )
{
screen.displayMessageLine( "\nWelcome!" );
authenticateUser();
}
performTransactions();
userAuthenticated = false;
currentAccountNumber = 0;
screen.displayMessageLine( "\nThank you! Goodbye!" );
}
}
private void authenticateUser()
{
screen.displayMessage( "\nPlease enter your account number: " );
int accountNumber = keypad.getInput();
screen.displayMessage( "\nEnter your PIN: " );
int pin = keypad.getInput();
userAuthenticated =
bankDatabase.authenticateUser( accountNumber, pin );
if ( userAuthenticated )
{
currentAccountNumber = accountNumber;
}
else
{
screen.displayMessageLine("Invalid account number or PIN. Please try again." );
}
}
private void performTransactions()
{
Transaction currentTransaction = null;
boolean userExited = false;
while ( !userExited )
{
int mainMenuSelection = displayMainMenu();
switch ( mainMenuSelection )
{
case BALANCE_INQUIRY:
case WITHDRAWAL:
case DEPOSIT:
currentTransaction = createTransaction( mainMenuSelection );
currentTransaction.execute();
break;
case EXIT:
screen.displayMessageLine( "\nExiting the system..." );
userExited = true;
break;
default:
screen.displayMessageLine("\nYou did not enter a valid selection. Try again." );
break;
}
}
}
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();
}
private Transaction createTransaction( int type )
{
Transaction temp = null;
switch ( type )
{
case BALANCE_INQUIRY:
temp = new BalanceInquiry( currentAccountNumber, screen, bankDatabase );
break;
case WITHDRAWAL:
temp = new Withdrawal( currentAccountNumber, screen, bankDatabase, keypad, cashDispenser );
break;
case DEPOSIT:
temp = new Deposit( currentAccountNumber, screen, bankDatabase, keypad, depositSlot );
break;
}
return temp;
}
}- Class Screen
public class Screen
{
public void displayMessage( String message )
{
System.out.print( message );
}
public void displayMessageLine( String message )
{
System.out.println( message );
}
public void displayDollarAmount( double amount )
{
System.out.printf( "$%,.2f", amount );
}
}import java.util.Scanner;
public class Keypad
{
private Scanner input;
public Keypad()
{
input = new Scanner( System.in );
}
public int getInput()
{
return input.nextInt();
}
}- Class Account
public class Account
{
private int accountNumber;
private int pin;
private double availableBalance;
private double totalBalance;
public Account( int theAccountNumber, int thePIN,
double theAvailableBalance, double theTotalBalance )
{
accountNumber = theAccountNumber;
pin = thePIN;
availableBalance = theAvailableBalance;
totalBalance = theTotalBalance;
}
public boolean validatePIN( int userPIN )
{
if ( userPIN == pin ) return true;
else return false;
}
public double getAvailableBalance()
{
return availableBalance;
}
public double getTotalBalance()
{
return totalBalance;
}
public void credit( double amount )
{
totalBalance += amount;
}
public void debit( double amount )
{
availableBalance -= amount;
totalBalance -= amount;
}
public int getAccountNumber()
{
return accountNumber;
}
}- Class BankDatabase
public class BankDatabase
{
private Account[] accounts;
public BankDatabase()
{
accounts = new Account[ 2 ];
accounts[ 0 ] = new Account( 12345, 54321, 1000.0, 1200.0 );
accounts[ 1 ] = new Account( 98765, 56789, 200.0, 200.0 );
}
private Account getAccount( int accountNumber )
{
for ( Account currentAccount : accounts )
{
if ( currentAccount.getAccountNumber() == accountNumber ) return currentAccount;
}
return null;
}
public boolean authenticateUser( int userAccountNumber, int userPIN )
{
Account userAccount = getAccount( userAccountNumber );
if ( userAccount != null )
return userAccount.validatePIN( userPIN );
else
return false;
}
public double getAvailableBalance( int userAccountNumber )
{
return getAccount( userAccountNumber ).getAvailableBalance();
}
public double getTotalBalance( int userAccountNumber )
{
return getAccount( userAccountNumber ).getTotalBalance();
}
public void credit( int userAccountNumber, double amount )
{
getAccount( userAccountNumber ).credit( amount );
}
public void debit( int userAccountNumber, double amount )
{
getAccount( userAccountNumber ).debit( amount );
}
}- Class CashDispenser
public class CashDispenser
{
private final static int INITIAL_COUNT = 500;
private int count;
public CashDispenser()
{
count = INITIAL_COUNT;
}
public void dispenseCash( int amount )
{
int billsRequired = amount / 20;
count -= billsRequired;
}
public boolean isSufficientCashAvailable( int amount )
{
int billsRequired = amount / 20;
if ( count >= billsRequired )
{
return true;
}
else
{
return false;
}
}
}- Abstract Class Transaction
public abstract class Transaction
{
private int accountNumber;
private Screen screen;
private BankDatabase bankDatabase;
public Transaction( int userAccountNumber, Screen atmScreen, BankDatabase atmBankDatabase )
{
accountNumber = userAccountNumber;
screen = atmScreen;
bankDatabase = atmBankDatabase;
}
public int getAccountNumber()
{
return accountNumber;
}
public Screen getScreen()
{
return screen;
}
public BankDatabase getBankDatabase()
{
return bankDatabase;
}
abstract public void execute();
}- Class Withdrawal
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;
}
}- Class Deposit
public class Deposit extends Transaction
{
private double amount;
private Keypad keypad;
private DepositSlot depositSlot;
private final static int CANCELED = 0;
public Deposit( int userAccountNumber, Screen atmScreen,
BankDatabase atmBankDatabase, Keypad atmKeypad,
DepositSlot atmDepositSlot )
{
super( userAccountNumber, atmScreen, atmBankDatabase );
keypad = atmKeypad;
depositSlot = atmDepositSlot;
}
@Override
public void execute()
{
BankDatabase bankDatabase = getBankDatabase();
Screen screen = getScreen();
amount = promptForDepositAmount();
if ( amount != CANCELED )
{
screen.displayMessage( "\nPlease insert a deposit envelope containing " );
screen.displayDollarAmount( amount );
screen.displayMessageLine( "." );
boolean envelopeReceived = depositSlot.isEnvelopeReceived();
if ( envelopeReceived )
{
screen.displayMessageLine( "\nYour envelope has been " +
"received.\nNOTE: The money just deposited will not " +
"be available until we verify the amount of any " +
"enclosed cash and your checks clear." );
bankDatabase.credit( getAccountNumber(), amount );
}
else
{
screen.displayMessageLine( "\nYou did not insert an " +
"envelope, so the ATM has canceled your transaction." );
}
}
else
{
screen.displayMessageLine( "\nCanceling transaction..." );
}
}
private double promptForDepositAmount()
{
Screen screen = getScreen();
screen.displayMessage( "\nPlease enter a deposit amount in " +
"CENTS (or 0 to cancel): " );
int input = keypad.getInput();
if ( input == CANCELED )
return CANCELED;
else
return ( double ) input / 100;
}
}- Class DepositSlot
public class DepositSlot
{
public boolean isEnvelopeReceived()
{
return true;
}
}- Class BalanceInquiry
public class BalanceInquiry extends Transaction
{
public BalanceInquiry( int userAccountNumber, Screen atmScreen, BankDatabase atmBankDatabase )
{
super( userAccountNumber, atmScreen, atmBankDatabase );
}
@Override
public void execute()
{
BankDatabase bankDatabase = getBankDatabase();
Screen screen = getScreen();
double availableBalance = bankDatabase.getAvailableBalance( getAccountNumber() );
double totalBalance = bankDatabase.getTotalBalance( getAccountNumber() );
screen.displayMessageLine( "\nBalance Information:" );
screen.displayMessage( " - Available balance: " );
screen.displayDollarAmount( availableBalance );
screen.displayMessage( "\n - Total balance: " );
screen.displayDollarAmount( totalBalance );
screen.displayMessageLine( "" );
}
}- Class ATMCaseStudy
public class ATMCaseStudy
{
public static void main( String[] args )
{
ATM theATM = new ATM();
theATM.run();
}
}
Untuk implementasinya, berikut saya tampilkan beberapa contohnya:
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