Creating a use-case diagram

Create a use-case diagram to describe the relationship between use cases and actors. You can define system boundaries and create associations between elements.

About this task

You can add existing (or shared) use-case and actor artifacts that contain textual use-case specifications; these artifacts can be reused in multiple diagrams. You can also add use-case and actors elements that function as placeholders; these placeholder elements cannot be reused in other diagrams. For more information, see Use cases.

For process guidance on creating use cases or actors, select a use case or actor in the diagram and click Help > Process Advisor.

To watch a movie that shows you how to create a use-case diagram, click here.

Procedure

  1. Click File > New > Use-Case Diagram.
  2. In the New Use-Case Diagram window, type a name for the diagram.
  3. Browse to a project and a folder for the new diagram.
  4. (Optional) Add a tag to the new diagram.
  5. (Optional) Select a template for initial content for the new diagram.
  6. (Optional) To add attribute groups to the diagram, click Next.
  7. Click Finish. The use-case diagram editor opens.
  8. To add an element to the diagram, from the Use Case Elements in the palette, select the element type and click in the diagram editor window.
  9. When you add a use case or actor, a search window opens. Enter a partial entry of the name of an existing use case or actor in the search field. Select the use case or actor and click OK.
  10. To move the element, click it and drag it to a new location in the diagram.
  11. To resize an element, click the element and drag a sizing handle in its selection frame.
  12. To rename an element, click the element and begin typing to replace the name, or double-click the element to edit the name. You cannot change the labels for shared actors and use cases; to change their names, you must open the artifacts.
  13. To reposition an association label, click the label and drag it to a new location.
  14. To edit an association label, select the association and begin typing, or double-click the association.
    Note: By default, if no label is defined, the label is not shown. After a label is defined, it is displayed. You can change this behavior in the preferences. You can also right-click an association and click Show/Hide label.
  15. To add text or a note to the diagram, in the palette, click the Note drop-down menu. Use a Note Attachment to associate a note with a particular element in the diagram.
  16. To convert a use-case placeholder to a use-case artifact so that it can be used in other diagrams and viewed as an independent artifact, right-click the use-case placeholder and click Save as a Use Case. To complete the information in the New Use Case Artifact window, see Creating a use-case artifact.
  17. To convert an actor placeholder to an actor artifact so that it can be used in other diagrams and viewed as an independent artifact, right-click the actor placeholder and click Save as Actor. To complete the information in the New Actor Artifact window, see Creating an actor artifact.
  18. To add a system boundary, select the System Boundary in the palette and drag it to the editor. You drag one or more use cases into the system boundary.
  19. Click File > Save and File > Close.

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