3 7 Use Case Diagram 2- extend, include, generalize, systems Purpose: describe relationships between use cases and subtypes of use cases or actors. DO NOT USE to show progress from one task to another! (See Activity Diagram.) Customer Include relationship: a dashed line with a dashed open arrowhead pointing from one use case to another use case that will always happen with the first. The line must be labeled with the Include stereotype. Extends relationship: a dashed line with a dashed open arrowhead pointing from a use case that might optionally occur along with the use case to which it points. The line must be labeled with the Extend stereotype. q Generalize relationship: a solid line with an empty triangular arrowhead drawn orthogonally from the more specific use case or actor (subtype) to the more general (supertype). System actors: other software systems (not the system being modeled) that participate in a use case are drawn as rectangles and usually labeled with the System> stereotype. Shapes . . Example search This table of actor roles and their associated use cases expands on an earlier model. Exercise 1 (use case diagram 2) - create a diagram Associated use cases Role Student Log in, view assignment, submit assignment Instructor Log in, view assignment, grade assignment, add comment (what's the same between Student and Instructor moves here!) User Gmail Notify student, notify instructor Draw a use case diagram in the space below. Show that both Student and Instructor are kinds of User. As part of grading an assignment, an Instructor might add a comment. When a student submits an assignment, the instructor will be notified through Gmail; when an instructor grades an assignment, the student will be notified.