1. Chapter 4: UML Interaction Diagrams

2. Objective Provide a reference for frequently used UML interaction diagram notation- sequence and communication diagrams.

3. 4.1. Sequence and Communication Diagrams Interaction diagram includes –sequence diagrams –communication diagrams Sequence diagrams –illustrate interactions in a kind of fence format each new object is added to the right Communication diagrams –illustrate object interactions in a graph or network format, objects can be placed anywhere on the diagram

4. 4.1. Sequence and Communication Diagrams public class A { private B myB = new B(); public void doOne() { myB.doTwo();myB.doThree();} // … }

5. 4.1. Sequence and Communication Diagrams

6. Sequence vs. Communication Diagrams? TypeStrengthsWeaknesses sequence clearly shows sequence or time ordering of messages large set of detailed notation options forced to extend to the right when adding new objects; consumes communication space economical flexibility to add new objects in two dimensions more difficult to see sequence of messages fewer notation options

7. 4.1. Sequence and Communication Diagrams Example Sequence Diagram: makePayment public class Sale { private Payment payment; public void makePayment( Money cashTendered ) { payment = new Payment( cashTendered ); //… } // … }

8. 4.1. Sequence and Communication Diagrams Example Communication Diagram: makePayment

9. 4.2. Novice UML Modelers Don't Pay Enough Attention to Interaction Diagrams! Spend time doing dynamic object modeling, not just static object modeling. –think through the concrete details of what messages to send, and to whom, and in what order, –that the "rubber hits the road" in terms of thinking through the true OO design details.

10. 4.3. Common UML Interaction Diagram Notation Illustrating Participants with Lifeline Boxes

11. 4.3. Common UML Interaction Diagram Notation Basic Message Expression Syntax return = message(parameter : parameterType) : returnType –Examples initialize(code)initialize d = getProductDescription(id) d = getProductDescription(id:ItemID) d = getProductDescription(id:ItemID) : ProductDescription d = getProductDescription(id:ItemID) : ProductDescription

12. 4.3. Common UML Interaction Diagram Notation Singleton Objects –only one instance of a class instantiated

13. 4.4. Basic Sequence Diagram Notation Lifeline Boxes and Lifelines

14. 4.4. Basic Sequence Diagram Notation Illustrating Reply or Returns

15. 4.4. Basic Sequence Diagram Notation Messages to "self" or "this"

16. 4.4. Basic Sequence Diagram Notation Creation of Instances

17. 4.4. Basic Sequence Diagram Notation Object Lifelines and Object Destruction

18. 4.4. Basic Sequence Diagram Notation Diagram Frames in UML Sequence Diagrams –Looping

19. 4.4. Basic Sequence Diagram Notation Frame Operator Meaning alt Alternative fragment for mutual exclusion conditional logic expressed in the guards. loop Loop fragment while guard is true. Can also write loop(n) to indicate looping n times. There is discussion that the specification will be enhanced to define a FOR loop, such as loop(i, 1, 10) opt Optional fragment that executes if guard is true. region Critical region within which only one thread can run. par Parallel fragments that execute in parallel.

20. 4.4. Basic Sequence Diagram Notation –Conditional Messages

21. 4.4. Basic Sequence Diagram Notation –Mutually Exclusive Conditional Messages

22. 4.4. Basic Sequence Diagram Notation –Iteration Over a Collection

23. 4.4. Basic Sequence Diagram Notation

24. public class Sale { private List lineItems = new ArrayList (); new ArrayList (); public Money getTotal() { Money total = new Money(); Money subtotal = null; for ( SalesLineItem lineItem : lineItems ){ subtotal = lineItem.getSubtotal(); total.add( subtotal ); total.add( subtotal ); } return total; return total; } // … }

25. 4.4. Basic Sequence Diagram Notation –Nesting of Frames

26. 4.4. Basic Sequence Diagram Notation How to Relate Interaction Diagrams?

27. 4.4. Basic Sequence Diagram Notation Messages to Classes to Invoke Static Methods public class Foo { public void doX() { // static method call on class Calendar Locale[] locales = Calendar.getAvailableLocales(); // … } // … }

28. 4.4. Basic Sequence Diagram Notation Polymorphic Messages and Cases

29. 4.4. Basic Sequence Diagram Notation Asynchronous and Synchronous Calls

30. 4.4. Basic Sequence Diagram Notation public class ClockStarter { public void startClock() { Thread t = new Thread( new Clock() ); // asynchronous call to the 'run' method on the Clock // asynchronous call to the 'run' method on the Clock t.start(); t.start(); // example follow-on message // example follow-on messageSystem.runFinalization(); } // … } // objects should implement the Runnable interface // in Java to be used on new threads public class Clock implements Runnable { public void run() { while ( true ) {// loop forever on own thread // … }} // … // …}

31. 4.5. Basic Communication Diagram Notation Links All messages flow on the same line

32. 4.5. Basic Communication Diagram Notation Messages Don't number the starting message.

33. 4.5. Basic Communication Diagram Notation Messages to "self" or "this"

34. 4.5. Basic Communication Diagram Notation Creation of Instances

35. 4.5. Basic Communication Diagram Notation Message Number Sequencing –The first message is not numbered. –The order and nesting of subsequent messages is shown with a legal numbering scheme in which nested messages have a number appended to them.

36. 4.5. Basic Communication Diagram Notation

38. Conditional Messages

39. 4.5. Basic Communication Diagram Notation Mutually Exclusive Conditional Paths

40. 4.5. Basic Communication Diagram Notation Iteration or Looping

41. 4.5. Basic Communication Diagram Notation Iteration Over a Collection

42. 4.5. Basic Communication Diagram Notation Messages to a Classes to Invoke Static Methods

43. 4.5. Basic Communication Diagram Notation Polymorphic Messages and Cases

44. 4.5. Basic Communication Diagram Notation Asynchronous and Synchronous Calls

45. Questions & Answers