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  1. OMG Issue

UML241 — Irritating occurrence of subsystem stereotype in use case example diagrams

  • Key: UML241-22
  • Legacy Issue Number: 16494
  • Status: closed  
  • Source: ( Florian Schneider)
  • Summary:

    Referenced UML Superstructure Version: 2.4 beta2


    In chapter 16 on use cases, a <<subsystem>> stereotype is applied to the subject (or system boundary) in three figures:

    • Figure 16.5 - Example of the use cases and actors for an ATM system (p. 614)
    • Figure 16.8 - Example of a use case for withdrawal and transfer of funds (p. 616)
    • Figure 16.11 - Use cases owned by a package (p. 621)

    According to Table B.1 - UML Keywords (p. 712), that specific stereotype is only applicable to Component. The subject of a use case is of type Classifier.

    So the named diagrams are not syntactically wrong but slightly irritating to the reader because there is no indication that in these examples, the use case subject is actually a more specific type of a classifier, namely a component. The diagrams could lead to misinterpretations like "it is allowed to use the subsystem stereotype for any use case subject".

    The textual description for Figure 16.5 does not clarify but only states "For example, the use cases shown in Figure 16.5 on page 614 apply to the “ATMsystem” classifier"
    Regarding Figure 16.8 the accompanying text makes no clarification.
    Figure 16.11 is even more confusing as it seems to be the case that the component being subject to the use cases is part of a package. Also the package name "ATMtopPkg" does not seem to be a good name for a package.


    1) Add textual description to explain the origin of the <<subsystem>> stereotype on the three diagrams
    remove subsystem stereotype as UML examples should not include constructs of any profile (even if it is one of the standard profiles)

    2) Rename "ATMtopPkg" in Figure 16.11 (e.g. to ATMNetwork)

  • Reported: UML 2.4 — Wed, 17 Aug 2011 04:00 GMT
  • Disposition: Resolved — UML 2.4.1
  • Disposition Summary:

    Merged with 18071

  • Updated: Fri, 6 Mar 2015 20:58 GMT