1. Interaction Diagrams Activity Diagram State Machine Diagram
Modeling Behavior
Interaction Diagrams
Activity Diagram
State Machine Diagram
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2. Learning Objectives
Understand how to represent system logic with interaction diagrams.
Understand how to represent system logic with activity diagram.
Understand how to represent system logic with state machine diagram.
Chapter 8 Appendix
© 2008 by Prentice Hall 2 2

3. UML Dynamic Modeling In all systems, events happen dynamically, e.g.:
Objects are created and destroyed
Objects send messages to one another
External events trigger operations on certain objects
Objects have states that would be difficult to capture in a static model
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4. UML Dynamic Modeling (cont.)
Behavior diagrams (dynamic):
Interaction diagrams
Sequence diagrams
Collaboration diagrams
Statechart diagrams
Activity diagrams
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5. Sequence Diagrams: An example
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6. Collaboration diagram: An Example
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7. When to use Interaction Diagrams?
Interaction diagrams are used when you want to model the behavior of several objects in a use case.  They demonstrate how the objects collaborate for the behavior. 
Interaction diagrams do not give a in depth representation of the behavior.  If you want to see what a specific object is doing for several use cases use a state diagram.  To see a particular behavior over many use cases or threads use an activity diagrams.
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8. Messages are passed between objects, and may contain parameters (e. g
Messages are passed between objects, and may contain parameters (e.g., message name (parameter list))

9. Sequence Diagrams
Describing the behavior of a system by viewing the interaction between the system and its environment
Shows the objects participating in the interaction by their life lines and the messages they exchange
Shows an interaction arranged in a time sequence
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10. Elements of a sequence diagram
Objects: represented by boxes at top of diagram.
Lifeline: the time during which an object exists.
Messages: means by which objects communicate with each other.
Activation: the time period during which an object performs an operation.
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11. Objects/Classes activation lifeline Client ATMMachine SavingAccount
Insert ATM card
Request PIN
Enter PIN code
Verify PIN code
PIN valid
activation
Request amount
Enter amount
Process transaction
Transaction successful
Dispense cash
Print receipt
lifeline

12. Collaboration Diagrams
Also known as Communication diagrams
Represents a collaboration, which is a set of objects related in a particular context, and interaction, which is a set of messages exchanged among the objects within the collaboration to achieve a desired outcome
sequences of messages are shown by numbering
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13. :ATMMachine :Client :SavingAccount 1: insert ATM card
3: enter PIN code
7: enter amount
:ATMMachine
:Client
2: request PIN
6: request amount
10: dispense cash
11: print receipt
4: verify PIN code
8: process transaction
5: valid PIN code
9: transaction successful
:SavingAccount

14. Sequence Vs Collaboration
Sequence Diagram:
Dynamic behavior of a set of objects arranged in time sequence, new objects added to the right
Good for real-time specifications and complex scenarios
easier to read
Collaboration Diagram :
Shows the relationship among objects.
Does not show time
Objects are arranged in a graph or network format
Both are used to examine the behavior of objects within a single use case
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15. How to draw sequence diagram?

16. Drawing Sequence Diagrams
Determine the context of the sequence diagram
Identify the object that are participate in the sequence
Set of the lifeline for each object
Lay out of messages from the top to the bottom of the diagram based on the order in which they sent
Add the execution occurrence to each object’s lifeline
Validate the sequence diagram

17. Identifying Classes/Objects
Noun phrase approach – read through the requirements or use cases looking for noun phrases
Some classes are implicit or taken from general knowledge
Carefully choose and define class names
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18. Use Case: Withdraw saving
A customer wants to draw money from his bank account. He enters his card into an ATM (automated teller machine). The ATM machine prompts “ Enter PIN”. The customer enters his PIN. The ATM (internally) retrieves the bank account number from the card. The ATM encrypts the PIN and the account number and sends it over to the bank. The bank verifies the encrypted account and PIN number. If the PIN number is correct, the ATM displays, “Enter Amount”. Draws money from the bank account and pays out the amount.
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19. Use Case: Withdraw saving
Actors: Bank Client
Flow of Events:
Bank client insert ATM card into ATM machine
ATM machine request PIN code
Bank client enter PIN code
Verify PIN code entered with saving account
ATM machine request amount if the PIN is valid
Bank client enter the required amount
Process the transaction in the client account
ATM machine dispense cash
ATM machine print receipt when the transaction completed
Alternative Flow of Events
Invalid PIN code entered. Indicate error message. Return step 3.
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20. Identifying Classes – noun phrase approach (example)
ATM System
Bank Client
ATM Card
ATM Machine
Savings Account
Cash
Message
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21. Client ATMMachine SavingAccount Insert ATM card Request PIN
Enter PIN code
Verify PIN code
PIN valid
Request amount
Enter amount
Process transaction
Transaction successful
Dispense cash
Print receipt

22. Another example …
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23. Display message to client
ATM System
ATM approval
Deposit amount
Client
Withdraw amount
Use case: ATM approval
Insert ATM card
Request PIN
Enter PIN
Verify PIN
Display message to client

24. Client ATM Machine ClientDatabase Use case: ATM approval
Insert ATM card
Request PIN
Enter PIN
Verify PIN
Display message to client

28. Use case: Withdraw amount Request withdrawal amount
ATM System
ATM approval
Deposit amount
Client
Withdraw amount
Use case: Withdraw amount
Request withdrawal amount
Enter withdrawal amount
Check account
Verify sufficient funds
Eject cash

29. Object naming Syntax: [objectName]:[className]
Include object (instance) names when objects are referred to in messages or when several objects of the same type exist in the diagram
Name classes consistently with your class diagram
Object A: Class A
Object B: Class B
:User
messageA()
messageB(“string”)
messageC()

30. Stereotypes of Analysis Classes
Classes or objects can be classified into one of the following three stereotypes:
Entity – to hold data
Boundary – used by actors to interact with the system
For example: Customer place order, interact using a order form.
Control – coordinating behavior in the system
For example: control the activities in the transaction (i.e., rules, calculations)

31. Stereotypes of Analysis Classes
Is an object relation that is extended to include responsibilities

32. Stereotypes of Analysis Classes
Is an object relation that is extended to include responsibilities

33. Stereotypes of Analysis Classes
A boundary class provides the interface between an actor and use case. The actor can be a human or an external system.
Encapsulates connections between actors and use cases

34. Stereotypes of Analysis Classes
A boundary class provides the interface between an actor and use case. The actor can be a human or an external system.
Encapsulates connections between actors and use cases

35. Stereotypes of Analysis Classes
A control class coordinates the tasks and captures the main logic in a use case.
Mostly performs behaviors associated with inner workings of use cases

36. Typically, actors interact with boundary classes, which in turn interact with control classes, which in turn interact with entity classes.

39. Operations (behaviors) are depicted in the lower third of a class box.
Operations fulfill the class’s responsibilities.

40. Activity Diagram State Diagram
Modeling Behavior
Activity Diagram
State Diagram
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41. Activity Diagram: An example
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42. When to use Activity Diagram?
The main reason to use activity diagrams is to model the workflow behind the system being designed. 
Activity Diagrams are also useful for: analyzing a use case by describing what actions need to take place and when they should occur;  describing a complicated sequential algorithm;  and modeling applications with parallel processes.
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43. Activity Diagram
Focus on flow of activity of internal process in object
similar to flowchart
describe changes in activity in a procedure
information from use case scenario or event flow can be used to describe activity diagram.
Used to provide detail for complex algorithms
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44. Activity Diagram (cont.)
Purpose:
Modeling human task
Describe system’s function
Describe logic operation
Elements in activity diagram:
Activity
Transition
Decision
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45. Example of Activity Diagram for Register Course
start
Fill form
Select course
[No]
Submit to PA
approve?
[Yes]
Register course
end

46. Example of Activity Diagram for ATM Authorization
Enter card
Read card
Request PIN
Enter PIN
[No]
Verify PIN
valid?
[Yes]
Select other service

47. Swimlane
partition an activity diagram so that parts in the swimlane relevant to that activities in the partition
helpful in investigating responsibilities for interactions and associations between objects and actors
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49. Top synchronization bar is a fork.
Activity diagram with synchronization bars – split into multiple paths and multiple paths combined into a single transition
Top synchronization bar is a fork.
Bottom synchronization bar is a join.
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50. OOAD

51. When to use State Diagram?
Use state diagrams to demonstrate the behavior of an object through many use cases of the system. 
Only use state diagrams for classes where it is necessary to understand the behavior of the object through the entire system
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52. What is a State Diagram?
A diagram that captures the behavior of an object by specifying the sequence of states it goes through during its lifetime in response to events, together with the responses to those events
describe changes in state in a procedure
Also called statechart diagram or state machine diagram
State – a condition or situation during the life of an object at which time it satisfies some condition, performs some activity, or waits for some event.
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53. What is a State Diagram? (cont.)
A state diagram to describe the behavior (i.e., state changes) of a single class according to events and messages which class sends and receives
A state diagram can also clarify a use case – to specify the actions the use case can take in accordance with varying conditions of the system
E.g., a use case ‘enroll course’, the state can be full, opened, and closed.
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54. State Diagram Example Paying Paid Unpaid Invoice created
Invoice destroyed
Paying
Paid
Unpaid

55. Transition Notation
Event(parameters) [condition] /action
State 1
do/activity 1
State 2
. . .
Start state
transition
End state
Example: Event(parameters) [condition]
mouse_button_clicked(right_button)[inside the window]
Example: /action
/calculate amount

56. State Notation
Name compartment
Action labels
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58. Recap After studying this chapter we learned to:
Understand how to structure requirements with interaction diagram, activity diagram and state machine diagram.
Explain the element of sequence diagrams, activity diagram and state machine diagram.
Construct sequence diagrams, activity diagram and state machine diagram