1. USE CASE Bayu Adhi Tama, MTI bayu@unsri.ac.id Faculty of Computer Science, University of Sriwijaya Slides are adapted from Petrus Mursanto (santo@cs.ui.ac.id)santo@cs.ui.ac.id

2.  To outline the functionality of the system.  To define what will be handled by the system and what will be handled outside the system.  To define who and what will interact with the system.  How to create diagrams of the use-case model.  How to create the use-case specification. Objectives

3. A use case describes a sequence of actions of a system performs that yields a result of value to a particular actor. A series of user – system interactions that helps the user to accomplish something. What is use case?

4.  Does ATM provide?  Does a library information system provide? What kind of services...

5.  A use case describes a process.  A process describes, from start to finish, a sequence of events, actions, and transactions required to produce or complete something of value to an organization or actor. e.g. Withdraw cash from an ATM, Register for courses at school, etc. Use case and Domain Process

6.  Actor-based:  Identify the actors related to a system or organization.  For each actor, identify the process they initiate or participate in.  Event-based:  Identify the external events that a system must respond to.  Relate the events to actors and use cases. Identifying Use Case

7.  An actor is an entity external to the system who in some way participates in the story of the use case.  There is one initiator actor who generates the starting stimulus, and possibly several other participating actors.  Kind of actors include: roles that people play, computer systems, electrical or mechanical devices Actor

8. To find the actors, ask the following questions:  Which user groups require help from the system to perform their tasks?  Which user groups are needed to execute the system's most obvious main functions?  Which user groups are required to perform secondary functions, such as system maintenance and administration?  Will the system interact with any external hardware or software system? Find Actors

9. A use case diagram illustrates a set of use cases for a system, the actors, and the relation between the actors and use cases. Use Case Diagram

10. Assume that we have been requested to create the software to run a point-of-sale terminal. Point of Sale (POS) Terminal (1) POS Terminal system boundary

11. Point of Sale (POS) Terminal (2) POS Terminal checkout boundary

12.  UC Specification in ATM System: Withdraw Money 1.The use case begins when a client inserts a card into the ATM. The system reads and validates information on the card. 2.The system prompts for a personal identification number (PIN). Client enters the PIN. The system validates the PIN. 3.The system asks which operation the client wishes to perform. Client selects “Withdraw Money”. 4.The system requests the amount of withdrawal. Client enters amount. Use Case Specification

13. UC Specification in ATM System: Withdraw Money 5.The system request the account type. Client selects the account type (checking, saving, credit). 6.The system communicates with the ATM network to validate the account ID, PIN, and availability of the amount requested. 7.The system asks the Client whether a receipt is desired. This step is performed only if there is paper available to print the receipt. 8.The system asks the Client to remove the card. Client removes the card. 9.The system dispenses the requested amount of cash. 10.The system prints a receipt, if required, which ends the use case. Use Case Specification

14. Example  Use case: Buy Items  Actors: Customer (initiator), Cashier  Description: A Customer arrives at a checkout with items to purchase. The Cashier records the purchased items and collects payment. On completion, the Customer leaves with the items. Use Case Specification

17.  Name a use case starting with a verb in order to emphasize that it is a process.  Buy Items  Enter an Order  Maintain Customer Profiles Naming Use Case

18. Include UC Relationship

19. Extend UC Relationship

20. Library Information System

21. Undergraduate’s point of view

22. Library Information System Postgraduate’s point of view

23. Library Information System Lecturer’s point of view

24. Library Information System Librarian’s point of view

25. Library Information System UC Library Information System

26. Library Information System UC Library Information System (REVISED)