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  1. OMG Issue

UML14 — UML2 Super / Classes / Operation constraints

  • Key: UML14-543
  • Legacy Issue Number: 7366
  • Status: closed  
  • Source: Simula Research Laboratory ( Dr. Bran Selic)
  • Summary:

    Currently, the UML 2 specification defines Operation properties precondition, postcondition, and bodyCondition that are owned constraints. However, these properties do not subset the Namespace::ownedRule property, but rather the Namespace::ownedMember property.

    The opposites of these properties are preConstraint, postConstraint, and bodyConstraint, all of which are non-navigable and subset Constraint::context and Constraint::namespace.

    Also, the Constraint::namespace property, which is non-navigable, subsets Constraint::context, which is navigable. This is inconsistent, and in fact violates the UML's own constraint on property subsetting which stipulates that a navigable property can only be subsetted by a navigable property (constraint [4] of metaclass Property).

    The consequence of all this is that a Constraint that is the precondition (for example) of an Operation does not have a context . This means that a constraint such as an OCL expressions in pre-conditions cannot be parsed against the context namespace.

    There are (at least) two ways to solve this problem:
    let Operation::precondition and its cohorts subset Namespace::ownedRule instead of Namespace::ownedMember (which would leverage the eContainer() "cheat" that EMF offers to get the owner of an element that doesn't have a navigable owner property)
    let Constraint::namespace redefine NamedElement::namespace and make it navigable, thus making the subset relationship with Constraint::context valid

    The first option seems preferred, for two reasons:
    It makes sense that all constraints that a namespace owns should be included in the ownedRule property
    This would be consistent with the Behavior metaclass, whose precondition and postcondition properties do subset ownedRule

  • Reported: XMI 2.0 — Thu, 20 May 2004 04:00 GMT
  • Disposition: Resolved — UML 1.4.2
  • Disposition Summary:

    see above

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