Module 4: Sequence diagrams
UML sequence diagrams (also called message structure charts) show the interaction between objects that exist in the system at runtime. Related diagrams include the collaboration diagram. In order to introduce the concepts, the module firstly explains collaboration diagrams, and in particular the need for these diagrams to show instances (objects) and not classes. Then, the sequence diagram is examined in detail.Lecture material
- Sequence diagrams :: Powerpoint :: PDF
Tutorial
In the tutorial, students need to to firstly identify a set of collaborating objects. They do this based on the CRC cards created in the earlier tutorial and follow-up work).
Then, they need to identify one or more use cases that used these objects. Having done so, they should sketch out collaboration diagrams for each use case. It is important that they understand that the collaboration diagram is not a representation of the use case -- just that the user actions of the use case indicate key triggers for the behavior in the collaboration diagram.
Finally, they should produce one or more sequence diagrams. As much as anything else, the purpose of the exercise is to introduce them to the notation, so it is not as important at this stage that the diagrams are correct as that the students have engaged with the notation and are then able to work further on the sequence diagrams outside of class time.
Self-study module
This module covers exploring and modelling object interactions with UML sequence diagrams.
- Sequence diagrams :: pdf
Resources
- UML 2 Sequence Diagrams, Scott Ambler
http://www.agilemodeling.com/artifacts/sequenceDiagram.htm - UML 2 Sequence Diagramming Guidelines, Scott Ambler
http://www.agilemodeling.com/style/sequenceDiagram.htm - UML 2 Communication Diagrams, Scott Ambler
http://www.agilemodeling.com/artifacts/communicationDiagram.htm - UML 2 Communication Diagramming Guidelines, Scott Ambler
http://www.agilemodeling.com/style/collaborationDiagram.htm