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  1. OMG Issue

UMLR — Navigability orthogonal to end ownership or not?

  • Key: UMLR-257
  • Legacy Issue Number: 16350
  • Status: open  
  • Source: ( Adam Ciążyński)
  • Summary:

    At one point (page 42) the specification reads:
    "Navigability notation was often used in the past according to an informal convention, whereby non-navigable ends were assumed to be owned by the association whereas navigable ends were assumed to be owned by the classifier at the opposite end. This convention is now deprecated. Aggregation type, navigability, and end ownership are orthogonal concepts, each with their own explicit notation."

    The same thought can be found here: :
    "... an old constraint from UML 1.x when navigability meant the same as ownership of property"

    However at another place (page 38) the specification reads:
    "An end property of an association that is owned by an end class or that is a navigable owned end of the association indicates that the association is navigable from the opposite ends; otherwise, the association is not navigable from the opposite ends."

    So is navigability orthogonal to end ownership or not? I think that the specification is somewhat unclear concerning these issues.

    The descriptions of ownedEnd and navigableOwnedEnd don't clarify much and seem to be too brief.

  • Reported: UML 2.3 — Tue, 28 Jun 2011 04:00 GMT
  • Updated: Fri, 6 Mar 2015 20:57 GMT