Using SUCD to Describe Use Cases ECE 621

Authoring Styles Many authoring styles exist Tailored for specific domains  Real-Time systems  Safety critical systems Most authoring styles use templates Overwhelming majority only use unstructured natural language Very little structure

SUCD Provides rigor Helps clarify the flow of use cases Helps avoid common mistakes Can be used to automatically generate the corresponding use case diagrams, hence ensures consistency

Headers an actions {BEGIN enter member information}  Librarian  enters member’s name  Librarian  enters member’s address  Librarian  enters member’s phone number {END enter member information} The Same A Header Actions The Actor

Basic Flow {BEGIN Use Case} … Headers and Actions …. {END Use Case} Reserved only for the Basic Flow

Alternative Flow AT {enter ticket order information} PERFORM search tickets IF tickets not available … Headers and Actions … The condition The Header in the Basic Flow The action in that header from the Basic Flow

Subflows SUBFLOW print receipt {BEGIN print transaction information}  SYSTEM  prints Customer information  SYSTEM  prints team hockey card information  SYSTEM  print items information and total price {END print transaction information} Subflow name

Extension Points – At The Base Use Case Extension Points: PUBLIC EXTENSION POINT Grand Prize Giveaway Name of the extension point

Extension Points – At The Extension Use Case PUBLIC EXTENSION POINT BEHAVIOR EXTENDING {Buy Team Merchandise : Grand Prize Giveaway} FLOW Basic Flow AT {a chance to win} IF winning ticket was entered {BEGIN grand prize giveaway}  SYSTEM  notifies Customer the he/she won the grand prize  Customer  enters phone number for a Customer service representative to call {END grand prize giveaway} CONTINUE {END Use Case} Name of the extended UC Name of the extension Point The flow inside the base UC Where to continue at base UC

Abstraction, Implementation and Specialization Keywords used in the Name section:  ABSTRACT  IMPLEMENTS  SPECIALIZES

More Keywords (2) INCLUDE – to perform an inclusion UC PERFORM – to performed a Subflow RESUME – what to perform next AFTER – what needs to be performed first AT/IF – what condition to evaluate and where BEGIN/END – PUBLIC EXTENSION POINT – at the base UC PUBLIC EXTENSION POINT BEHAVIOR – at the extension UC PRIVATE EXTENSION POINT – private to the UC FLOW – which flow in the base UC CONTINUE – where to go back in the base UC