1. Modern Systems Analysis and Design Fifth Edition Jeffrey A
Modern Systems Analysis and Design Fifth Edition Jeffrey A. Hoffer Joey F. George Joseph S. Valacich
Appendix
Object-Oriented Analysis and Design: Sequence Diagrams and Activity Diagrams

2. Learning Objectives
Understand how to represent system logic with sequence diagrams.
Understand how to represent system logic with activity diagrams.
Chapter 8 Appendix
© 2008 by Prentice Hall

3. Dynamic Modeling: Sequence Diagrams
Sequence diagram: depicts the interactions among objects during a certain periods of time.
May be presented either in a generic form or in an instance form.
Generic form shows all possible sequences of interactions – sequences corresponding to all the scenarios of a use case.
Instance form shows the sequence for only one scenario.
Chapter 8 Appendix
© 2008 by Prentice Hall

4. Dynamic Modeling: Sequence Diagrams (Cont.)
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.
Chapter 8 Appendix
© 2008 by Prentice Hall

5. Dynamic Modeling: Sequence Diagrams (Cont.)
Activation: the time period during which an object performs an operation.
Synchronous message: a type of message in which the caller has to wait for the receiving object to finish executing the called operation before it can resume execution itself.
Chapter 8 Appendix
© 2008 by Prentice Hall

6. Dynamic Modeling: Sequence Diagrams (Cont.)
Simple message: a message that transfer control from the sender to the recipient without describing the details of the communication.
Asynchronous message: a message in which the sender does not have to wait for the recipient to handle the message.
Chapter 8 Appendix
© 2008 by Prentice Hall

7. Designing a Use Case with a Sequence Diagram
Figure 8-11 Sequence diagram for a class registration scenario without prerequisites
Chapter 8 Appendix
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8. Designing a Use Case with a Sequence Diagram
Figure 8-12 A generic sequence diagram for the
“Prerequisite Courses Not Completed” use case
Chapter 8 Appendix
© 2008 by Prentice Hall

9. A Sequence Diagram for Hoosier Burger
Figure 8-13 Sequence diagram for Hoosier Burger’s Hire Employee use case
Chapter 8 Appendix
© 2008 by Prentice Hall

10. Process Modeling: Activity Diagrams
Activity Diagrams: shows the conditional logic for the sequence of system activities needed to accomplish a business process.
Clearly shows parallel and alternative behaviors.
Can be used to show the logic of a use case.
Chapter 8 Appendix
© 2008 by Prentice Hall

11. Process Modeling: Activity Diagrams (Cont.)
Figure 8-14 Activity diagram for a customer order process.
Chapter 8 Appendix
© 2008 by Prentice Hall

12. Process Modeling: Activity Diagrams (Cont.)
Elements of Activity Diagrams:
Activity: a behavior that an object carries out while in a particular state.
Transition: a movement from one activity or state to another.
Branch: a diamond symbol containing a condition whose results provide transitions to different paths of activities.
Chapter 8 Appendix
© 2008 by Prentice Hall

13. Process Modeling: Activity Diagrams (Cont.)
Synchronization bar: horizontal or vertical bars denoting parallel or concurrent paths of activities.
Fork: the beginning of parallel activities.
Join: the end of parallel activities.
Swimlanes: columns representing different organizatonal units of the system.
Chapter 8 Appendix
© 2008 by Prentice Hall

14. Summary In this appendix you learned how to:
Understand how to represent system logic with sequence diagrams.
Understand how to represent system logic with activity diagrams.
Chapter 8 Appendix
© 2008 by Prentice Hall