Interfaces
It is possible to complement the description of a use case or actor by describing the interfaces by which it communicates with its environment.
To create an interface:
1. Click the
Interface button

in the insert toolbar.

If the
Interface button does not appear in the toolbar, select
View Views and Details and select
Classes.
2. Click in the diagram.
3. In the dialog box that appears, enter the name of the interface and click the Create button.
The interface appears in the diagram.
To specify the interface supported by a use case:

Click the

button and drag the link from the use case (eg: Process Order) to the interface (eg: Order Interface).
The link then appears in the diagram.
You can detail which operations the use case can carry out via this interface.
To indicate the interface required by a use case:

Click the

button and draw the link between the use case and the interface.