Diagrams


Description

Use Case Diagrams are a specialization of Class Diagrams such that the classifiers shown are restricted to being either Actors or Use Cases.

Graphic Nodes

The graphic nodes that can be included in structural diagrams are shown in Table 22.

Table 22 - Graphic nodes included in sequence diagrams


NODE TYPE NOTATION REFERENCE
Actor (default)
See "Actor (from UseCases)"
Actor (optional userdefined
icon -example)

Extend
See "Extend (from UseCases)" 
Extend (with Condition)
Extension- Point
See "ExtensionPoint (from UseCases)"

Include
See "Include (from UseCases)"
Use Case
See "UseCase (from UseCases)"






Examples



The use case diagram in Figure 409 shows a set of use cases used by four actors of a physical system that is the subject of those use cases. The subject can be optionally represented by a rectangle as shown in this example.

Figure 410 illustrates a package that owns a set of use cases (NB: a use case may be owned either by a package or by a classifier (typically the classifier specifying the subject)).



Changes from previous UML


There are no changes from UML 1.x, although some aspects of notation to model element mapping have been clarified.