Use Case diagram Tutorial 2 What is a

Use Case diagram Tutorial 2

What is a UML Use Case Diagram? �Use case diagrams model the functionality of a system using actors and use cases. Use cases are services or functions provided by the system to its users. �Use Case diagrams show the interactions between use cases and actors Done By: Hala Al-Zagear 2

Basic Use Case Diagram Symbols and Notations 1. System �Draw your system's boundaries using a rectangle that contains use cases. Place actors outside the system's boundaries. Done By: Hala Al-Zagear 3

Basic Use Case Diagram Symbols and Notations 2. Actors �Actors are the users(person, system) of a system. When one system is the actor of another system, label the actor system with the actor stereotype. Done By: Hala Al-Zagear 4

Basic Use Case Diagram Symbols and Notations 3. Use Case �Draw use cases using ovals. Label with ovals with verbs that represent the system's functions. �The use cases should be named in user terms, not technical terms, and should be meaningful to the customer. Done By: Hala Al-Zagear 5

Basic Use Case Diagram Symbols and Notations 4. Relationships �Draw relationships between an actor and a use case with a simple line. �For relationships among use cases, use arrows labeled either "uses" or "extends. " �A "uses, or include" relationship indicates that one use case is needed by another inorder to perform a task. � An "extends" relationship indicates alternative options under a certain use case. Done By: Hala Al-Zagear 6

Basic Use Case Diagram Symbols and Notations Done By: Hala Al-Zagear 7

Bank ATM Examples �An automated teller machine (ATM) is a banking subsystem that provides bank customers with access to financial transactions in a public space without the need for a cashier, clerk or bank teller. �Customer (actor) uses bank ATM to check balances of his/her bank accounts, deposit funds, withdraw cash and/or transfer funds (use cases). ATM Technician provides maintenance and repairs. All these use cases also involve Bank actor whether it is related to customer transactions or to the ATM servicing. Done By: Hala Al-Zagear 8

use case diagram for Bank ATM subsystem Bank Done By: Hala Al-Zagear 9

Include & extended Relationship �On most bank ATMs, the customer is authenticated by inserting a plastic ATM card and entering a personal identification number (PIN). Customer Authentication use case is required for every ATM transaction so we show it as include relationship. �If needed, customer may ask ATM for help. ATM Transaction use case is extended via Menu extension point by the ATM Help use case whenever ATM Transaction is at the location specified by the Menu and the bank customer requests help, e. g. by selecting Help menu item. Done By: Hala Al-Zagear 10

Include & extended Relationship Done By: Hala Al-Zagear 11