1. Use Case Modeling - techniques for detailing use cases
Chapter 5 pp: ,
Use Case Descriptions
Activity Diagrams (also read Ch2: 60-63)
CRUD Analysis

2. Outline Describing Use Cases in more detail Use Case Descriptions
Activity Diagrams
also read Ch2: 60-63
Validating Use Cases – using CRUD Analysis

3. 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.

4. Use Case Description – “Brief”
Create
Customer
account
Customer
Use Case Description
“Brief”

5. Use Case Description – “Fully Developed”
Create
Customer
account
Customer

6. Use Case Description – “Fully Developed”
Use case name – e.g. Create Customer Account
Scenario – unique path through this use case (Create Online Customer Account)
Triggering event – external, temporal, state
Brief description – summary of Flow of Activities
Actors – actual user(s)
Related use cases – includes or extends
Stakeholders – vested interest
Preconditions – any object/system that must be available before the use case
Post conditions – objects/associations created/updated during the use case
Flow of activities – actor and system swimlanes showing interactions
Exception conditions – what prevents the use case from completing

7. UML's Activity Diagram

8. UML Activity Diagram a graphical representation of procedural flow
Activities
People, System(s)
Flow
Sequential, conditional, repetition
Used to model 2 things:
Business Processes (BPM) -also read Ch2: 60-63
Use Case (Ch 5)

9. Activity Diagram – Symbols
For Concurrency….
Synchronization Bar
Fork
Swimlane
Loop
contains activities performed by a single agent (actor, organizational unit)
For each item
Join
End for each item
Starting
Activity
Ending
Activity
Output cannot execute
until all inflows have been received
Decision
Merge
Activity/Action
[guard]
Transition/Activity Edge

10. Activity Diagram – Issue a Quote
Use this notation for decisions
- i.e. include the [guards]
[guard]

11. Forks, Joins, and Decisions
Option 1: A E D C B
Option 2: F

12. Practice: Activity Diagram & Use Case Description
Use Case Name: “Create New Sale for Contractor (on credit)”
Use Case Description:
A contractor initiates a purchase by taking materials 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.
There is an additional use case called “Create a New Cash Sale”.

13. Practice: Activity Diagram

14. Practice: Use Case Description
Use case name
Create a New Sale
Scenario
Creating a new sale for contractors (on credit)
Triggering event
Contractor wants to purchase items
Brief description
Contractor bring items to checkout desk. Clerk validates his account and credit limit. Clerk scan items. System looks up price, records items, and compares total to credit limit. The system creates a ticket with all items and reduces the credit limit. A ticket is printed upon request.
Actors
Clerk
Related use cases
None: includes or extends
Stakeholders
Sales clerk, Sales department, Accounting department
Preconditions
Account must exist; Inventory items must exist
Post conditions
Sale is created, Sale line items are created and connected to the sale. Account is updated, Inventory is reduced
Flow of activities
Actor
System
Clerk enters customer name
Clerk scans items
Clerk indicates end of the sale
1.1 System validates account 2.1 System creates a Sale
2.2 System looks up item 2.3 System adds item to Sale 3.1 System calculates total amount
3.2 System reduces credit limit
Exception conditions
1.1 If account is out of balance, initiate "Create a New Cash Sale" use cases
2.2 If item is not found, clerk calls manager and manually enters item information 3.1 If amount is greater than credit limit, initiate "Create a New Cash Sale" use case

15. Validating Use Cases - CRUD Analysis
Can be a tool for: use case identification and/or validation
Ensure that there are use cases to cover the CRUD
CRUD - For 1 data entity C R U D
CRUD Matrix
All use cases
All data entities
Shows responsibilities

16. CRUD CRUD Use Cases Place order Change order Cancel order
Print order report
Update customer profile
View order status …
Order C
Create R
Read U
Update D
Delete
CRUD Matrix
Use Cases
Order
OrderItem
Customer
Item
Place order
Update Customer Profile …