Use Case

• Use case icon: ellipse;
• Use case name: a label inside or below the ellipse icon;
• Use case documentation: textual description (optional);
• Use case generalisation to inherit behaviour;
• Use case extension stereotypes <<include>> (to include factored out common behaviour) and <<extend>> (to extend into variants by adding extra behaviour)
• A typical use of a Computer System by an external user (actor) involving one or more sequences of actions in the system on behalf of the user;
• Capture of a system functionality (user requirement) in a use case;
• Use case realized by a collaboration in the system;
• Use case instance manifests as a scenario;
• A use case encompasses all possible scenarios for it.