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

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

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

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

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

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

Designing a Use Case with a Sequence Diagram Figure 8-11 Sequence diagram for a class registration scenario without prerequisites Chapter 8 Appendix © 2008 by Prentice Hall

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

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

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

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

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

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

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