"ExternalSystem" visualized as a cuboid ???

[dagraf]

Hi,

in pertinent literature there is used an "ExternalSystem" visualized as a cuboid in Use-Case Diagrams.
There is also a poster from OOSE where such an "ExternalSystem" is displayed.

Now my question is if an "ExternalSystem" is part of the UML Standard and if this is the case is this element is available in EA?  :-?

Best Regards,
Daniel  

[Oliver F.]

An external system is not part of the UML spec.
However there are several ways of dealing with system parts or use cases outside of the system in question:

- Use boundaries to model the system specific parts and keep the others outside the boundary. The disadvantage: This is not reflected in the model
- Use stereotypes for external components and use cases and support those with an appropriate shape script.

A combination of both of course looks like the optimum.

Oliver

[Yves C]

In UML an external system which interacts with the system you consider is by definition an actor. However you want to distinguish between human and system.
You can use an actor and use the rectangle notation to show it. In the use case diagram, right clic on the actor, select "Advanced" then "Use rectangle notation".
You can also use a stereotype "system" to denote that this actor is a system.

[bioform]

Rectangle Notation NOT just for external system!

By right clicking the Use Case, and then selecting the "Feature Visibility" option, you can then using the "Show Element Compartments" check boxes, turn On or Off the display of various compartments.

I turn on: Responsibiliteis, Tags, Constraints, and Notes.

In my models, each use case "owns" a diagram that presents a quick overview of the use case in one quick look.

• Responsibilities - Internal Requirements of the Use Case
• Tags - Additional metadata about the use case
• Constraints - I use these to document pre & post conditions for the UC
• Notes - I use this area to describe the scope of the use case.

Pretty handy stuff! Remember, if you don't have any information defined in those areas, the "compartments" will not be shown.

Last thing, when you use of the rectangular notation it only applies to that diagram (dropping the UC on another diagram will use the default notation, the ellipse)

Think WE all covered that question pretty well!

David