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16.4 Diagrams

*Description

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

*Graphis Nodes

    The graphic nodes that can be included in structural diagrams are shown in Table 16.1 .

Table 16.1 - Graphic nodes included in use case diagrams

Node Type

Notation

Reference

Actor (default) Customer See Actor (from UseCases ) on page 612.
Actor (optional user-defined icon example)

Extend Perform ATM Transaction «extend» extension points Selection extended (use case) extending (use case) See Extend (from UseCases ) on page 615.
Extend (with Condition) «extend» Condition: {customer selected HELP} extension point: Selection

   Table 16.1 - Graphic nodes included in use case diagrams Table 16.1 - Graphic nodes included in use case diagrams

Node Type

Notation

Reference

ExtensionPoint extension points Selection extension point See ExtensionPoint (from UseCases ) on page 617.
extension points order created : in Created state order shipped : in Shipped state OrderStationery extension point
Include Withdraw Card Identification «include» including use case included use case See Include (from UseCases ) on page 619.

Node Type

UseCase

Notation

Reference

Withdraw See UseCase (from UseCases ) on page 620.
On-Line Help
Perform ATM Transaction extension points Selection
OrderStationery

*Examples

   use case

   Telephone Catalog


   Check Status


   


Salesperson


   


Place Order

   actor

   Customer


   


Shipping Clerk

   Fill Orders


   subject


   Establish Credit

   Supervisor

   Figure 16.10 - UseCase diagram with a rectangle representing the boundary of the subject

    The use case diagram in Figure 16.10 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 16.11 illustrates a package that owns a set of use cases.Note – A use case may be owned either by a package or by a classifier (typically the classifier specifying the subject).

Figure 16.11 - Use cases owned by a package

   package ATMtopPkg

   1

   Administrator

*Changes from previous UML

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