bank

Class ATM

java.lang.Object

bank.ATM

public class ATM
extends java.lang.Object

Class whose objects represent the automated teller machines of our bank. These machines can operate both online and offline. In the first case, all transactions are directly transfered to the central host of the bank, in the latter case transactions are first buffered (using class OfflineAccountProxy and later written back to the central host.

Constructor Summary

Constructors

Constructor and Description
ATM(CentralHost centralHost)

Method Summary

Methods

Modifier and Type	Method and Description
int	accountBalance() Determine the balance of the current account.
void	confiscateCard() Confiscate an inserted card.
BankCard	ejectCard() Eject an inserted card
void	enterPIN(int pin) Enter the PIN the belongs to the currently inserted bank card into the ATM.
void	insertCard(BankCard card) Insert the given card into the ATM.
void	requestAccountStatement() Request a printed account statement for the current account
void	setOnline(boolean newOnline) Switch the status of this ATM to online or offline.
int	withdraw(int amount) Try to withdraw amount from the current account.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ATM

public ATM(CentralHost centralHost)

Method Detail

setOnline

public void setOnline(boolean newOnline)

Switch the status of this ATM to online or offline. Switching to online will make the terminal write back all buffered transactions to the central host and remove all account proxies. TODO: one of the places where both complete specification and verification are non-trivial

Parameters:

newOnline - true iff the terminal is switched online

insertCard

public void insertCard(BankCard card)

Insert the given card into the ATM. This will check whether the card is invalid or the card belongs to a non-existing account (if the terminal is online); in this case the card is directly confiscated

Parameters:

card - the card to be inserted

ejectCard

public BankCard ejectCard()

Eject an inserted card

Returns:

the card that was inserted previously

confiscateCard

public void confiscateCard()

Confiscate an inserted card. This invalidates the card; afterwards, the card is no longer regarded as inserted

enterPIN

public void enterPIN(int pin)

Enter the PIN the belongs to the currently inserted bank card into the ATM. If a wrong PIN is entered three times in a row, the card is confiscated. After having entered the correct PIN, the customer is regarded is authenticated

Parameters:

pin - the PIN that is entered

accountBalance

public int accountBalance()

Determine the balance of the current account.

Returns:

the balance of the current account, provided that the balance is available (only in the online case). Otherwise 0 is returned TODO: make online a precondition?

withdraw

public int withdraw(int amount)

Try to withdraw amount from the current account. TODO: make specification stronger, say something about the return value?

Parameters:

amount - the amount that is supposed to be withdrawn

Returns:

the amount of money that was sucessfully withdrawn (i.e. in case of failure the return value is 0)

requestAccountStatement

public void requestAccountStatement()

Request a printed account statement for the current account