1. System Sequence Diagrams(SSD)
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2. System Sequence Diagrams(SSD)
A system sequence diagram (SSD) is a fast and easily created artifact
Used to illustrates input and output events related to the systems.
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3. System Sequence Diagrams(SSD)
Use cases describe how external actors interact with the software system.
During this interaction an actor generates system events to a system, usually requesting some system operation to handle the event.
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4. System Sequence Diagrams(SSD)
For example when a cashier enters an item's ID, the cashier is requesting the POS system to display item name
Which is an event generated by cashier.
A SSD is a picture that shows, events that actor generate, and their order, in one scenario of a use case.
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5. System Sequence Diagrams(SSD)
Example of SSD
The Figure is an example for the success scenario of a cash-only Process Sale scenario.
It indicates that the cashier generates makeNewSale, enterItem, endSale, and makePayment system events.
These events are represented through the use case text.
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6. System Sequence Diagrams(SSD)
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7. SSDs and Use Cases
An SSD shows system events for one scenario of a use case; therefore it is generated from inspection of a use case
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8. SSDs and Use Cases
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9. SSDs Within the UP
SSDs are part of the Use-Case Model—a visualization of the interactions implied in the use cases.
SSDs are an example of the many possible skillful analysis and design artifacts or activities that the UP do not mention.
Inception—SSDs are not usually used in inception.
Elaboration—Most SSDs are created during elaboration, when it is useful to identify the details of the system events to clarify what major operations the system must be designed to handle
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