ATM Case Study

Users may view their balance or transfer or withdraw money using these cards.. • Enter a new card / new account detail • Block /Reactivate/Cancel a card • View the balance of the account

ATM Case Study

A Discussion

Case Study

A Bank wishes to introduce ATM service to provide

limited facilities to her customers Customers may get ATM cards on request Users may view their balance or transfer or withdraw money using these cards Cards

may be used to access many accounts and an account may be accessed using different cards A card may be blocked temporarily or permanently (e.g If it is lost) by the Bank A PIN is associated with each card to verify the authority of the user There is an OD limit associated with each cheque account Theoretically, any amount

may be withdrawn from a cheque account at any time (provided it is less than the balance+Odlimit) There is

no OD facility for a savings account.

Case Study (cty)

The personal information of the customers and their account details are already maintained by the Bank’s main system A subsystem is required

to handle the ATM’s functionality Two hardware systems Card reader and Money dispenser will communicate with this subsystem The card

reader reads the Card’s ID and passes it to the system It is also able to eject the card when an eject signal is received from the system

Similarly the money dispenser is able to

dispense the required amount of money

Case Study-3

The Limited ATM system is required to provide at least the following operations

• Enter a new card / new account detail

• Block /Reactivate/Cancel a card

• View the balance of the account

• Withdraw money from the account

• Transfer money from one account to another

• Change the PIN of a card

The validity of the card and the authority of the

User will be checked for each transaction session

Apply for Card

Assign Pin Finalise Card

:Card [Recorded]

:Card [Approved]

:Card [Finalised]

:Card [active]

• ATM Card

• Withdraw

-Requirement List

• Client shall view the balance

• Client shall withdraw money within a limit

• Client shall change the PIN

• Bank Clerk shall store a new CARD detail

• Bank Clerk shall add another account to a CARD

• Shall check the CARD’s validity

• Shall verify the PIN

• Shall use 3-DCS (168 bits) encoding

Grouping the Candidate Requirements

CARD MANIPULATION

– Clerk store a new CARD detail

– Clerk add another account to a CARD

– Clerk & Client shall fix new PIN first time

– Client shall change the PIN

Structures added

add new account

add new card

fix PIN

Use Cases Card Manipulation

Client

Add structures 

add new account

add new card

fix PIN

Use Cases Card Manipulation

Client

ATM- Withdraw From Current

Name : Withdraw From Current

Actor : Client

Pre-conditions : User already logged-in

A menu is active with ‘withdraw’ option Post-conditions : Amount is deducted from user’s account

Purpose : To allow the client to withdraw money

Description:

(1) Client initiates this usecase by selecting ‘withdraw’

(2) System get all the accounts (use case get Account)

(3) System displays all the accounts and prompts to select any one (3) Client selects one account

(4) System prompts for the amount

(5) Client indicate an amount

(6) System issues money, update record, and confirms

Alternative courses:

(3) & (4) System selects the only one available account

(6) requested amount is bigger than balance, system display message Errors:

Issue Cash?

Usecase Withdraw from Savings

Description-Prototype Withdraw from Current

ATM- Withdraw

System gets all accounts

Client selects Fast cash

Client Select One Account

Client selecetd withdraw

Displays all accounts [accounts>1]

Issue cash

Display message [amount > balance]

[Quit]

Complete other Usecases!

ATM ; E-R Diagram  Classes (ITE-1)

ATMSavings

ATMCard

custID getCustID()

accID balance oDlimit

cardNo pin

status

getAccID() setBalance() getBalance()

For the time being there is

no need for an Association

Realize Usecases

• Identify System’s Tasks

• Identify Collaborating Objects

• Draw Collobaration again

• Update Class diagram

Withdraw From Current

Name : Withdraw From Current

Actor : Client

Pre-conditions : User already logged-in

A menu is active with ‘withdraw’ option Post-conditions : Amount is deducted from user’s account

Purpose : To allow the client to withdraw money

Description:

(1) Client initiates this usecase by selecting ‘withdraw’

(2) System get all the accounts (use case get Account)

(3) System displays all the accounts and prompts to select any one

(3) Client selects one account

(4) System prompts for the amount

(5) Client indicate an amount

(6) System issues money, update record, and confirms

Alternative courses:

(3) & (4) System selects the only one available account

(6) requested amount is bigger than balance, system display message

Errors:

Identify System’s Tasks

Identify Nouns

System’s Tasks Identified

• (1) System gets all the accounts on Card

• (2) System displays the details of Accounts

• (3) Prompts to select one

• (4 System prompts for the amount

• (5) System issue money

• (6) Update records (update what?)

How to allocate these tasks to different classes?

Use case Realization!

withdraw Client

:Account :Card

withdraw

1

Identify Collaborations

CRC - Allocate Responsibilities

Class Name Card

Provide Card information.

Class Name Account

Provide Account information.

Provide Withdrawal Provide list of Accounts. Account provides Account’s detail.

Collaboration Diagram (Initial Idea)!

getAllAccDetail() 2 *getAccDetail()1

withdraw(acc,amm)

ATMCustomer ATMChequeATMSavings

ATMCard

custID getCustID()

accID balance oDlimit accName

cardNo pin status

getAccID() setBalance() getBalance()

getAccDetail() withdraw(amo)

Analysis Level Class Diagram (Ite-3)

ATMCustomer

ATMSavings

ATMCard

custID getCustID()

cardNo pin status

getAccDetail() withdraw(amo)

accID balance accName

1 *

Analysis Level Class Diagram (ver-2)

ATMCustomer

ATMSavings

ATMCard

custID getCustID()

cardNo pin status

getAllAccDetail()

1 *

1 1 *

getAccDetail() withdraw(amo)

accID balance accName

1 *

ATMCustAcc

with entity objects only

Use Case: withdraw

With Boundary & Control Classes

*getAccDetail() :withdrawUI

:withdrawCtrl :Card :Account

State Transitions

• Include relevant State Transition Diagrams (or Activity Diagrams)

Withdraw- Operation Specification

Pre- and Post-condition Pair

if amount is greater than ACCOUNT.balance

value of ACCOUNT.balance set equal to ACCOUNT.balance-amount

value of result set equal to success otherwise

value of result set equal to failure

Issue Cash?

Structured English- withdraw

get all the accounts associated with CARD

if there are more than one ACCOUNT

Do while there is no more ACCOUNTS left get all the details associated with ACCOUNT display details

endDo set ACCOUNT to user selected ACCOUNT else

set ACCOUNT to the only existing ACCOUNT endIf

if ACCOUNT.balance is greater than amount

set ACCOUNT.balance to ACCOUNT.balance – amount set result to TRUE

else

set result to FALSE endIf

return result

Get Account Details [NoOfAccounts = 1]

[amount < =A balance]

A.balance  A.balance-amount Result  TRUE

List an Account details

A  Only Account

Activity Diagram- Withdraw