Use case diagram

Model Parts, Diagrams, Dictionary Items, and Properties > Diagrams > Use case diagram

Use case diagram

For information about Use Case Modeling in Modeler, see Use case modeling overview.

A Use Case Diagram details the possible ways in which a system can be used, that is, the use cases, and the interaction of objects in the system to implement the use cases.

You can create a Use Case Diagram through the context menu of a Package: right-click the Package, point to New, point to UML, point to Use Cases, and then click Use Case Diagram. You can also create a Use Case Diagram for a Class, Data Type, Interface or Signal: right-click the item, point to New, and then click Use Case Diagram.

The following sections provide information about how a Use Case Diagram is used in the model. For more information about an item, property or model part, click it.

Shows these dictionary items

Like most diagrams, a Use Case Diagram can show variability items and relationships. See Overview of variability items and relationships on diagrams.

For most diagram symbols, you can change the presentation of the symbol through the Style view options (See Style view options - all diagrams), and change the showing of Stereotypes and Tag Definitions through the Stereotypes view options (See Stereotypes view options for a symbol - all diagrams). When a symbol has additional view options for changing its presentation, this icon

is shown - to see how the view options can change the presentation, click the

icon.

These items (which are not documented in the reference topics) can also appear on a Use Case Diagram:

• Extend Flow - indicates that a Use Case extends the activity of another. An extend flow points toward the Use Case that is extended. Extend flows can be used to represent alternative courses of action and exceptions. They are modeled as probes (with filled in nodes) on sequence diagrams.

• Frame Box

- provides a way of adding a box or background image to the diagram.

• Include Flow - indicates that a Use Case includes the activity of another, that is, the included Use Case is a common activity. An include flow points toward the Use Case that is included. Include flows can be used to deal with commonality and complexity in a high level Use Case Diagram. They are modeled as probes (with open nodes) on Use Case Diagrams.

• Note

- provides a way of adding text to the diagram.

• Note Link

- links a Constraint, Comment or Note to an item on the diagram.

Properties

A Use Case Diagram has these properties:

• Description

• Full Name

• Last Changed By

• Last Changed On

• Name

• Page Reference