Lecture 4: Use Case Realisation

Question 1

What are use case realisations?

Answer 1

The model shows how analysis classes realises the behaviour specified by the use case

• Each use case has exactly one realisation

Question 2

What are the 4 UC Elements?

Answer 2

1. Analysis Class Diagram
   - Show the relationship of the analysis class and use case
2. Interaction diagram
   - Show how objects realises a use case known as “snapshots”
3. Special requirements
   - UC may uncover new requirements to be captured in a use case
4. Use Case refinement
   - Discovers new information during the realisation

Question 3

What is an interaction?

Answer 3

• Is the behaviour between the classifier
  - shows the behaviour by the use case being realised

Question 4

What two interactions does the diagram capture?

Answer 4

1. Lifelines
   What a single participant is as a interaction that represents an instance of an specific classifier
2. **Messages **
   Communicates between lifelines

Question 5

What does a lifeline contain?

Answer 5

1. Name used in interaction
2. Selector, Boolean condition
3. Type of classifier

Question 6

What does a lifeline looklike? What is the syntax from the textbook?

Question 7

How many realisation does a use cases have?

Answer 7

Every ues case has only ONE use case realisation

Question 8

What does a lifeline/interaction represent?

Answer 8

Represents a single participant in the interaction

Question 9

What two ways can a asynchronous message be used?

Answer 9

• A process/thread SENDS‘go to sleep’
• A process defines a call back’ operation by the transport message is delivered

Question 10

Name the 4 interaction diagrams

Answer 10

1. Sequence diagram
   - Interacts by sending message in a time sequence
   - Rich diaragm, expensive
2. Communication diagram
   - Relationships between lifelines
   - Uses communication diagrams to make other relationships
3. Interaction diagrams
   - Complex behaviour is realised by a set of simplier interactions
4. Time diagrams
   - Uses timing aspects

Question 11

What does self-delegation do?

Answer 11

Self-delegation is when a lifeline sends a message to itself

Question 12

What does self-delegation create?

Answer 12

Nested activation

Question 13

What are combined fragments?

Answer 13

• Sequence diagrams can be divided into areas called the interaction fragments
• Operands as combined fragments “groups”

Question 14

What is a communication diagram?

Answer 14

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· Structural aspects of an interaction, how lifelines connect

Question 15

What is branching?

Answer 15

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· <!--[endif]-->Modelled by prefixing the sequence number with a guard condition

Question 16

What is the interaction overview diagram?

Answer 16

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· <!--[endif]-->Model high level flow of control between interactions

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· <!--[endif]-->Shows interactions and occurrences

Question 17

What is an operator and guard condition?

Answer 17

Operator: HOW its operand executes
Guard Condition: WHETHER their opperands execute condition