UML14 — Notation for Namespace ownership

The contents of a package (i.e. the ownedElements of the Namespace of
the the package) can be shown in two different ways: either enclosed by
the package symbol or attached with the encircled plus sign (figure 3-6
in the Notation Guide).

Even though classes are also namespaces, then the same options do not
apply for them. In fact there is no notation for this at all. It is
possible to have class boxes enclosed by a class box, but it has another
mapping than notation elements being enclosed graphically by a package
symbol: according to 3.47.5 of the Notation Guide "A class box with
contained class boxes maps into a set of composition associations;".

One may argue that packages are different from classes, but subsystems
come close to objects. A Subsystem (in its capacity of being a Package)
have the two options of showing the contents, i.e. it is possible to
have class boxes within the Subsystem symbol. The meaning of this should
be (according to the text on Package) that the classes are defined
within the Subsystem. However, the Semantics of Subsystem says that "the
semantics of an instantiable susbsystem is similar to the semantics of a
composite class", which means that the enclosed class boxes should be
interpreted in the same way as for class boxes enclosed by a class
boxes.

The enhancement of this should be that notation for namespace
"containment" (ownedElement) and object containment (composition) should
be clarified and made similar for similar concepts.

No Data Available