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Reading a UML Activity Diagram
publish date: 2026/06/08 03:53:21.067339 UTC
volume_mute
The diagram below shows part of the involuntary patient detention process modeled as a UML activity diagram.
Which UML notation element is used in this diagram to show that the dangerous and not dangerous paths are mutually exclusive alternatives?
Correct Answer
A diamond shape (decision node)
Explanation
A diamond shape is used as a decision node in UML activity diagrams to represent a point where the flow splits into mutually exclusive alternatives based on guard conditions shown in square brackets (e.g., [dangerous] and [not dangerous]). A solid bar is a synchronization/fork bar for concurrent flows. A filled circle marks the start. Rounded rectangles represent activities.
Reference
Software Engineering, Ian Sommerville, 9th edition