In Unified Modeling Language (UML) sequence diagrams,
a guard condition, or an interaction constraint, is a semantic condition
or restriction in an interaction operand within a combined fragment.
You can add guard conditions to interaction operands.
You must have a sequence diagram that contains
at least one combined fragment with multiple lifelines open in the diagram
editor.
To add a guard condition to an interaction operand:
- In the diagram editor, right-click an interaction
operand that has no existing guard condition; then click .
- Click the field, type the guard condition, and press
Enter.