UML Sequence Diagrams
About the UML Sequence Diagram
A UML sequence diagram provides insight and an overview of object interactions arranged in a time sequence. It illustrates the objects and classes involved in a scenario, as well as the sequence of messages exchanged between objects necessary to perform the required functionality.
When to Draw a UML Sequence Diagram?
A UML sequence diagram shows the scenario (flow of events) in one single use case. The flow of messages in the sequence diagram is based on the story told by a use case.
If you want to draw a sequence diagram, you normally need to draw a use case diagram and describe what the use case in question does.
The Elements of a Sequence Diagram
A sequence diagram consists of elements:
- Lifeline Notations
- Activation Bars
- Message Arrows
Below you see three examples of these elements:
UML Lifeline notation with an Actor symbol
UML Activation bar
UML Message Arrows
Model your UML diagram on the Dragon1 Platform
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