Constraints

If you need to define the conditions and rules under which an element operates and exists, you can do this by setting Constraints on the element, in conjunction with responsibilities (internal requirements). Typical constraints are pre- and post- conditions, which indicate things that must be true before the element is created or accessed and things that must be true after the element is destroyed or its action is complete.

You can show the constraints for an element directly on the diagram, using the Feature Visibility function; this also reveals any constraints inherited from parent elements.

Access    Double-click element > Constraints

Define constraints for an element

Field/Button

Description

See also

New

Click on this button to clear the fields ready to create a new constraint.

 

 

Constraint

Type the value of the constraint.

 

 

Type

Click on the drop-down arrow and select the appropriate type (Pre-condition, Post-condition or Invariant).

 

 

Status

Click on the drop-down arrow and select the appropriate status.

 

 

Notes

Type any additional information required.

 

 

Save

Click on this button to save the constraint data.

 

 

OK

Click on this button to close the dialog.

 

 

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