A use case is typically specified as a sequence of interactions between the subject and the various actors, which are all modeled as part usages. The objective of the use case is to provide an observable result of value to one or more of its actors. 

A use case can have only one subject and objective.

Specifying subjects, actors, and objectives for use cases

Specifying subjects, actors, and objectives for use cases via Textual Editor

To specify subjects, actors, and objectives for use cases via Textual Editor

  1. In the Textual Editor, within the curly braces of the use case's body, do the following:
    1. To specify a subject, declare the subject keyword, specify the element name, specialization (optional).
    2. To specify an actor, declare the actor keyword, specify the element name, specialization (optional).
    3. To specify an objective, declare the objective keyword, then in the element body, declare a documentation.
  2. Click the Synchronize button.

    use case def 'Provide Transportation' {
        subject vehicle : Vehicle;                       // use case subject
        actor driver : Person;                             // use case actor
        actor environment : Environment;
        objective {                                             // use case objective
            doc /* Transport driver and passengers from starting location to ending location. */
        }
    }

Specifying subjects, actors, and objectives for use cases via the Drag and Drop handler in a view

To specify subjects, actors, and objectives for use cases via the Drag and Drop handler in a view

  • Drag and drop an element from the Containment tree or use its symbol's Drag and Drop handler on a use case element symbol, executing the Create Subject, Create Actor, Create Objective, or Create Require Constraint of Objective command.
  • Drag and drop an element from the Containment tree or use its symbol's Drag and Drop handler on the specific subject or actor displayed on the use case element symbol, executing the Set Subsetted Feature command.

Specifying subjects, actors, and objectives for use cases via the symbol compartment in a view 

For more information, see the Creating elements via compartments on the Compartments page.

To specify subjects, actors, and objectives for use cases via the symbol compartment in a view 

  • Do one of the following:
    • Select a use case symbol and click the Create Element button on it. In the dropdown menu, select the element you want to create. The new element is created and displayed in its appropriate compartment.
    • Select a use case symbol and on the right side of the actors compartment, click the Create actor button. The new element is created and displayed in the actors compartment.

Specifying subjects, actors, and objectives for use cases via the Specification panel

To specify subjects, actors, and objectives for use cases via the Specification panel

  1. Open the Specification panel.
  2. Do one of the following:
    1. In the Properties section bar, click the Create Element button. The shortcut menu appears. Click the needed element kind in the shortcut menu.
    2. In the actors compartment section's bar, click the Create actor button.
      The element is created in the appropriate compartment.