Tags and keywords
This content has been marked as discussing an ADVANCED topic!
Some clarifying and myth-busting about frequently misunderstood aspects of UseCases and their notations:
The first common misunderstanding is that just because a UseCase symbol appears inside the rectangle of a subject Classifier does not mean that it is owned by that Classifier and can only have that one Classifier as subject:
UML-2.5.1: 'UseCases need not be owned by their subject.'
UML-2.5.1: 'A UseCase may be owned either by a Package or by a Classifier. Although the owning Classifier typically represents a subject to which the owned UseCases apply, this is not necessarily the case ...'
UML-2.5.1: 'Note also that the subject rectangle does not imply that the subject classifier owns the contained UseCases, but merely that the UseCases apply to that classifier.'The second common misconception concerns the notation itself. A Classifier (such as a SysML Block) acting as a subject may different on a UseCase Diagram than in other diagrams:
UML-2.5.1: 'A subject for a set of UseCases (sometimes called a system boundary) may be shown as a rectangle with its name in the top-left corner, with the UseCase ellipses visually located inside this rectangle.'