Use case diagram - where is system boundary?

[Dan]

Hi all,

My first post after having just 'discovered' bouml.

I'm working through the diagrams and wondered if the 'add subject' button is in effect the use case system boundary?

Thanks.

[Bruno Pagès]

Hi,

the 'add subject' button is in effect the use case system boundary?

Absolutely, an extract of the norm ( https://www.omg.org/spec/UML/2.5.1/PDF §18.1.4 page 641) :

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.

I write the subject's name centered but it must be on the left, I will change that

[Dan]

Hi,

Thanks for the reply.

I did not know that system boundary was also called 'subject' !

For me system boundaries in case diagrams are a 'hint' to what
sub systems there may be when I move onto design, as I may
use the same system boundary name in different diagrams.

So would it be possible to add the following features?

1. The name of a system boundary should be unique, so adding one to a
diagram allows a new name to be entered and a list of already existing
system boundaries.

2. Ability to add user defined stereotype e.g. <<sub-system>> to a system
boundary element and if set to be displayed.

3. Ability to see what systems boundaries a use case belongs to.

4. Ability to see a list of system boundaries and what case cases 'belong' to each.

Thanks,

Dan.

[Bruno Pagès]

I did not know that system boundary was also called 'subject' !

The truth is in the norm, even it is not always easy to read

For me system boundaries in case diagrams are a 'hint' to what
sub systems there may be when I move onto design, as I may
use the same system boundary name in different diagrams.

Referring to the norm "subject" only exist for the use cases, so it is normal to see them in use case diagram but not in others

In the other diagrams I encourage you to use the packages or "combined fragment"

1. The name of a system boundary should be unique, so adding one to a
diagram allows a new name to be entered and a list of already existing
system boundaries.

Warning, a use case diagram can be partial and can show only a part of a subsystem for instance rather than all of it, so a given subject can appears in several diagrams, several subjects can appear in a diagram, and a given subject can also appears several times in a diagram to help it to be readable. Then I will not introduce constraint in the use of the subjects in the use case diagrams.

2. Ability to add user defined stereotype e.g. <<sub-system>> to a system
boundary element and if set to be displayed.

I attach default stereotypes only to the element types visible in the browser, and as you can see the subjects aren't visible in the browser. Furthermore when you edit a subject you cannot specify separately the stereotype and the name, so you have to enter the stereotype and the name at the same time.

3. Ability to see what systems boundaries a use case belongs to.
4. Ability to see a list of system boundaries and what case cases 'belong' to each.

For me the best way is to define (sub) use case views having the name the subjects and to define the associated use cases into them in the browser

[Dan]

Hi,

It looks like UML has changed quite a bit since I last used it!

I take your points about system boundary - it may be that
"combined fragment" is what I need to use - I did not look at
that as I did not know what is was - I've looked as some UML
web pages and there are not very clear either.

One problem is that the BOUML help only only jumps to a general page with
instructions on how to add items to diagrams etc but there are not many
definitions of the items themselves.

It would be very helpful to have a Glossary at the end of the help pages,
as some programs differ in their usage of terms.

At the moment I'm working on an extension to a home grown c++
game project and I'm trying to use BOUML to capture some new
features - so bear with me ... there may be more questions !

Thanks,

Dan.

[Bruno Pagès]

...
I write the subject's name centered but it must be on the left, I will change that

Hello,

The release 7.6 is available and fix that problem

Regards