Use case

Question 1

What is a use case

Answer 1

A tool to analyse and communicate functional requirements.

Question 2

Describe use case

Answer 2

The system’s behaviour as it responds to a request from the actor.
Describes the sequence of steps to achieve the goal.

Question 3

Casual use case examples

Answer 3

Actor
System
Goal
Scope
Main sequence

Question 4

Trigger definition

Answer 4

Specifies the event that gets the use case started.
(What causes the actor to start it).

Question 5

Pre conditions

Answer 5

Explains the state that the system must be in for the use case to be able to start.

Question 6

Guarantees definition

Answer 6

The outcome, what must be true after the use case has occurred.

Question 7

Guarantees type

Answer 7

Success guarantee and Minimum guarantee.

Question 8

Success guarantee definition

Answer 8

The use case succeeds

Question 9

Minimum guarantee

Answer 9

The use case ends.

Question 10

Withdraw cash use case primary actor example

Answer 10

customer

Question 11

Withdraw cash use case goal

Answer 11

Withdraw cash

Question 12

Withdraw cash use case scope

Answer 12

Cash machine

Question 13

Main sequence

Answer 13

1. The customer inserts their card in machine
2. The system validates the card and prompts the customer to
   enter PIN code.
3. The customer enters the PIN and selects the OK option on
   screen
4. The system validates the PIN entered and displays the
   Options Menu Screen.
5. The customer selects the ‘Cash Withdrawal’ option from the
   Options Menu.
6. The system prompts the customer to enter the amount of
   cash that they wish to withdraw
7. The customer enters a cash amount and selects the OK
   option on screen

Question 14

A fully dressed use case

Answer 14

–Supporting actors
– Stakeholders
– Trigger
– Preconditions
– Main sequence
– Extensions
– Guarantees (success and minimum)

Question 15

Actor definition

Answer 15

A stakeholder who interacts
with the system during the use case.

Question 16

Primary Actor

Answer 16

who starts it off

Question 17

Supporting Actor

Answer 17

A user who provides a service.

Question 18

Stakeholder definition

Answer 18

Someone with a vested interest in the behaviour of the use case.

Question 19

Withdraw cash use trigger example

Answer 19

Customer decides to withdraw cash.

Question 20

Withdraw cash use preconditions

Answer 20

The Cash Machine is operational; the bank
customer has a valid card and PIN

Question 21

Withdraw cash use case success guarantee

Answer 21

– Customer has the goods they need
– Atom has been paid for the goods

Question 22

Withdraw cash use case minimum guarantee

Answer 22

• Everything supplied has been paid
  for, OR
• Credit has been cancelled