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Extending the Requirements Model - techniques for detailing use cases . Use Case Descriptions - Chapter 5 pp : 119-124 Activity Diagrams - Chapter 5 pp : 125-126; and Chapter 2 pp 57-60. Where are we?. Outline. Describing Use Cases in more detail Use Case Descriptions ( Ch 5)
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Extending the Requirements Model- techniques for detailing use cases Use Case Descriptions - Chapter 5 pp: 119-124 Activity Diagrams - Chapter 5 pp: 125-126; and Chapter 2 pp 57-60
Outline • Describing Use Cases in more detail • Use Case Descriptions (Ch 5) • Activity Diagrams (Ch5 & Ch2)
Use Case Description • Describes the details for a given use case • Various levels of details • Brief (Ch 3) • Intermediate • Fully developed ATM System Withdraw cash Use Case Description (brief version) Actor inserts a bank card and PIN, and the system sends the account number and PIN number to the bank for verification. Actor enters a withdrawal amount, and the system requests the bank’s authorization, creates a transaction record, and dispensing cash.
Use Case Description – “Brief” Create Customer account Customer Use Case Description “Brief”
Use Case Description – “Fully Developed” Create Customer account Customer
Use Case Description – “Fully Developed” • Use case name • Scenario • Triggering event • Brief description • Actors • Related use cases • Stakeholders • Preconditions • Post conditions • Flow of activities • Exception conditions
UML Activity Diagram • a graphical representation of procedural flow • Activities • People, System(s) • Flow • Used to model 2 things • Entire Business Processes or Workflows (Ch 2) • Can be use for Business Process Modeling (BPM) • A Single Use Case (Ch 5)
Activity Diagram – Symbols Synchronization Bar • Used for concurrency Swimlane Join Split/Fork • contains activities performed by a single agent (actor, organizational unit) Output cannot execute until all inflows have been received Loop Starting Activity Ending Activity • End for each item • For each item in … Decision Merge Activity/Action [guard] Transition/Activity Edge [guard]
Activity Diagram – Issue a Quote Use this notation for decisions - i.e. include the [guards] [guard] [guard]
Activity Diagram – Order Fulfillment Use this notation for decisions - i.e. include the [guards] [guard] [guard]
Forks, Joins, and Decisions Bad waiting for 4 activities to finish Good Merge!
Practice: Activity Diagram & Use Case Description • Use Case Scenario for “Creating a New Sale for a Contractor (on credit)”. Quality Building Supply has two kinds of customers: contractors and the general public. Sales to each are slightly different. A contractor buys materials by taking them to the checkout desk for contractors. The clerk enters the contractor's name into the system. The system displays the contractor's information, including his/her current credit standing. The clerk then opens up a new ticket (sale) for the contractor. Next, the clerk scans in each item to be purchased. The system finds the price of the item and adds the item to the ticket. At the end of the purchase, the clerk indicates the end of the sale. The system compares the total amount against the contractor’s current credit limit, and if it is acceptable, finalizes the sale. The system creates an electronic ticket for the items, and the contractor’s credit limit is reduced by the amount of the sale. Some contractors like to keep a record of their purchases, so they request that the ticket details be printed. Others aren’t interested in a printout.
