This chapter describes each model element that can be created within a use case diagram. Note that some sub-model elements of model elements on the diagram may not actually themselves appear on the diagram.

There is a close relationship between this material and the properties tab of the details pane (see Section 13.3, “Properties Tab”). That section covers properties in general, in this chapter they are linked to specific model elements.

Figure 17.1, “Typical model elements on a use case diagram.” shows a use case diagram with all typical model elements displayed.

Figure 17.1. Typical model elements on a use case diagram.

17.1.1. ArgoUML Limitations Concerning Use Case Diagrams

Use case diagrams are now well supported within ArgoUML. There still are some minor limitations though, especially with extension points.

	Note
	Earlier versions of ArgoUML (0.9 and earlier) implemented extend and include relationships by using a stereotyped dependency relationship. Although such diagrams will show correctly on the diagram, they will not link correctly to the use cases, and should be replaced by proper extend and include relationships using the current system.