UNIT 3

1. UNIT 3 UNIT 3 • DYNAMIC MODELING Coming up: Interaction Diagrams

2. INTERACTIONS • Interaction diagrams are defined by UML to emphasize the communication between objects, not the data manipulation associated with that communication. • Interaction diagrams focus on specific messages between objects and how these messages come together to realize functionality. • Interaction diagrams show exactly how those objects will realize it. Coming up: Interaction Diagrams

3. You can show the details of an interaction using several different notations; however sequence diagrams are by far the most common. Other notations include interaction overviews, communication diagrams, timing diagrams Coming up: Interaction Diagrams

4. Sequence Diagrams

5. ELEMENTS OF SEQUENCE DIAGRAM

6. 1. Participants • Objects who participate in the communication. • Shown by a Rectangle.

7. EXAMPLE : Order Processing System : User ObjectName:ClassName

8. 2. Lifeline Coming up: Interaction Diagrams

9. 3. Messages • Shown as a solid line pointing from the sender's lifeline to the receiver's lifeline.

10. 3.1 Synchronous Message • If a message represents synchronous communication ( meaning the sender waits for the receiver to process the message), • You place a filled arrow head on the receiver's end.

11. 3.2 Asynchronous Message • If the message is an asynchronous message (meaning the sender doesn't wait for the receiver to process the message), • You place an open arrowhead on the receiver's end of the line.

12. Types of Messages Class 2 Class1

13. 3.3 Return values • Using a dashed line with an open arrowhead.

14. Type of Message ::: Elements : Order Processing System : User OrderItem (“UML in a Nutshell”) Confirmation Number

15. Summary of Messages

16. More About Scenario …. • Sequence Diagrams show how objects interact with each other and the order of occurrence. • They represent interactions for a particular scenario.

17. FROM USECASE DIAGRAM TO SEQUENCE DIAGRAM • Refine and expand each use case…

18. EXAMPLE

19. Create / Destroy Objects: Coming up: Interaction Diagrams

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21. TYPES OF MESSAGES • SYNC, ASYNC • Lost and Found Coming up: Interaction Diagrams

22. Found Message • You show a found message by starting the message from a black circle rather than the sender's lifeline. Coming up: Interaction Diagrams

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24. The CircuitBreaker doesn't care where the power surge came from; it must terminate the power in all conditions. Coming up: Interaction Diagrams

25. Lost Message Coming up: Interaction Diagrams

26. 4. EXECUTION OCCURRENCE • You can show an object is involved in executing some type of action (typically a method call) for a measurable amount of time using an execution occurrence. • Execution occurrences are shown as gray or white rectangles on a lifeline. • In practice, it is common to hear execution occurrences called "focus of control," Coming up: Interaction Diagrams

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28. 5. STATE INVARIANT • UML allows you to place labels along a lifeline to convey conditions that must be true for the remainder of the interaction to be valid. • These conditions are called state invariants . • State invariants are typically boolean expressions, Coming up: Interaction Diagrams

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30. 6. COMBINED FRAGMENT • 1. Critical • 2. Alt • 3. Opt • 4. Parallel • 5. Loop Coming up: Interaction Diagrams

31. Interaction Operator • Combined Fragment Coming up: Interaction Diagrams

32. 1. Critical • You may have a critical region within your interaction where a set of method calls must execute atomically Coming up: Interaction Diagrams

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34. 2. Alt • alternative interaction operator that models an if-else condition Coming up: Interaction Diagrams

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36. 3. Opt • Options are interaction fragments that executes only if the guard condition is True. • The interaction operator is opt. Coming up: Interaction Diagrams

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38. 4. Break • A break indicates that the associated interaction fragment operand should execute and then terminate the enclosing interaction. Coming up: Interaction Diagrams

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40. 5. Parallel • Parallel indicates that the associated interaction fragments may be merged and executed in parallel. The interaction operator is par. • UML specifies that the actual interleaving of the event occurrences of the operands must be done in such a way that the ordering in the original operand is maintained. Coming up: Interaction Diagrams

41. For example, if the first operand consists of: • Step1 • Step2 • Step3 • and the second consists of: • StepA • StepB • StepC Coming up: Interaction Diagrams

42. they can be merged into: Step1 StepA StepB Step2 StepC Step3 but not into: Step1 StepB Step2 StepA Step3 StepC Coming up: Interaction Diagrams

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44. 6. Loop • A loop indicates that the contained event occurrences are to be executed some number of times. • The interaction operator is loop. The notation for a loop includes a minimum and • maximum number of times a loop should execute. Coming up: Interaction Diagrams

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46. 6. COMBINED FRAGMENT • 1. Critical • 2. Alt • 3. Opt • 4. Parallel • 5. Loop Coming up: Interaction Diagrams

47. 7. INTERACTION OCCURRENCE Coming up: Interaction Diagrams

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49. 8. CONTINUATIONS • Typically used with interaction references, continuations allow you to define different branches of an alternative interaction outside of the alternative itself. • Only on those specific lifelines. Coming up: Interaction Diagrams

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