Quiz 5 Flashcards
What is an SSD?
An SSD is a picture that shows, for one particular scenario of a use case, interactions between external actors and the system
What do SSDs do for events shown by external actors?
For the events shown by external actors, an order is also shown
What do SSDs serve as input for?
Operation Contracts
When are most SSDs created?
Elaboration
What are operation contracts?
Descriptions of how Domain Model state changes for a system operation. Shows what needs to happen without going into implementation
Sections of a contract
Operation: Name and params
Cross References: Use cases operation occurs in
Preconditions: Assumptions about the state of the system or objects prior to the operation
Postconditions: State of objects in the Domain Model after completion of the operation
System Events
I/O Messages relevant to the system
Public System Interface
The entire set of system operations
Postconditions
Instances created, associations formed/broken, attributes changed
Operation
A specification of a transformation or query that an object may be called to execute
Method
Implementation of an operation
Object Constraint Language (OCL)
Can be used to express constraints of UML operations
When are most contracts written?
Elaboration
Design by contract (Meyernot)
- Condition assertion design
- Invariant Section
Invariant Section
Defines things that must not change during an operation
