Object-Oriented Sequence Diagrams

Object-Oriented Sequence Diagrams Week 10 CMIS 570

Plan for Tonight • Sequence diagrams • Turn in Use Case diagram • Turn in Oracle Process model • Hand out Sequence diagram homework and FHD homework

Sequence Diagrams • Illustrates the objects that participate in a use-case and the messages that pass between them over time for one use-case. • A dynamic model • Most similar to a DFD Level 0

Elements of a Sequence Diagram • Text • Objects • Message or interaction • Message Condition • Dotted Line • Focus of Control or Activation

Object creates Object • If object creates an object, message is sent directly to an object instead of its lifeline.

Creating a Sequence Diagram • 1. Copy text for use case from the use case specification. Paste it onto the left margin of the page. • 2. Identify Objects • 3. Add messages • 4. Place lifeline and focus of control

Examples • Rent a Car • Search by Author

TIPS • Don’t turn your sequence diagram into a flowchart • Update existing models

Modification of Class Diagram • Similar to DFDs and ERDs, after creating a Sequence Diagram, you may alter your Class Diagram.

For Next Class Meeting… • FHD/CRUD • Alternative Design Document

Object-Oriented Sequence Diagrams