Unformatted text preview: scenario
SSD for Process Sale scenario
(Larman, page 175) From Use Case to From Use Case to Sequence System Diagram How to construct an SSD from a use case:
2. 3. 4. Draw System as black box on right side For each actor that directly operates on the System, draw a stick figure and a lifeline.
For each System events that each actor generates
in use case, draw a message.
Optionally, include use case text to left of diagram. Example: use cases to SSD
Example: use cases to SSD Identifying the right Actor
Identifying the right Actor In the process Sale example, does the customer interact directly with the POS system? Who does?
Cashier interacts with the system directly
Cashier is the generator of the system events
Why is this an important observation? Naming System events & operations
Naming System events & operations System events and associated system operations should be expressed at the level of intent Rather than physical input medium or UI widget
Start operation names with verb (from use case)
Which is better, scanBarCode or enterItem? SSDs and the Glossary in parallel
SSDs and the Glossary Why is updating the glossary important when developing the SSD?
New terms used in SSDs may need explanation, especi...
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- Spring '14
- sequence diagrams