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  1. OMG Issue

MOF14 — Association Generalization Proposal

  • Key: MOF14-34
  • Legacy Issue Number: 4720
  • Status: open  
  • Source: Google ( Don Baisley)
  • Summary:

    Here is a detailed proposal for adding association generalization to MOF
    1.5. This proposal does not address reference redefinition or overriding.
    I hope this proposal provides sufficient detail so that Steve Crawley can
    make changes to the specification. Please send your comments.


    Changes to Model

    Remove constraints [C-34] AssociationsHaveNoSupertypes, [C-35]
    AssociationMustBeRootAndLeaf, and [C-36] AssociationsCannotBeAbstract.

    Add a nonabstract association from AssociationEnd to AssociationEnd called
    RedefinesEnd. One end is called redefinedEnd, has a reference by the same
    name, and has multiplicity *. The other end is called redefiningEnd, has no
    reference, and has multiplicity *. This association is used to correlate an
    end with its corresponding end in a supertype association.

    Add new constraint: SupertypeEndsAreRedefined
    Evaluation policy: Deferred.
    Description: An end redefines each supertype's end.
    Context Association
    Inv: self.supertypes.contents->select(gc | gc.oclIsTypeOf(AssociationEnd))->
    forAll(ge : AssociationEnd |
    self.contents->select(sc |
    forAll(se : AssociationEnd | se.redefinedEnd->exists(re | re =
    and se.otherEnd.redefinedEnd->exists(ore | ore =

    Add new constraint: RedefinedEndBelongsToSupertype
    Evaluation policy: Immediate.
    Description: Each redefinedEnd belongs to a supertype.
    Context AssociationEnd
    Inv: self.container.oclAsType(Association).supertypes.contents->

    By the way, I noticed a bug. [C-38] AssociationsMustBeBinary is an
    immediate constraint, but it should be deferred. Otherwise, there is no
    valid way to create an Association.

    Changes to Abstract Mapping

    Add the following to Core Association Semantics.

    A link cannot be directly created for an Association with isAbstract set to
    true, but can be added indirectly as a link of a subtype association.

    Where a generalization exists between two associations, each link of the
    subtype association is logically a link of the supertype association - for
    each subtype Link <a, b> there implicitly exists a supertype Link <a, b> (or
    <b, a> depending on which subtype end redefines which supertype end).

    Removing a link from a Link_Set causes the logical link to be removed from
    each subtype association's Link_Set. Removing a link from a Link_Set also
    causes the logical link to be removed from each supertype association's
    Link_Set where the logical link is not otherwise present in the supertype
    Link_Set based on either having been put explicitly into the supertype
    Link_Set (where not abstract) or on being a link of some other subtype of
    the supertype. The net effect is that a Link_Set is a union of links put
    explicitly into the Link_Set with the Link_Sets of all subtypes.

    Changes to IDL Mapping

    In the template for associations, no add or modify operations are generated
    for an abstract association.

    In the template for references, no set, add, or modify operations are
    generated for an abstract association.

    Operations on RefObject for setting, adding, and modifying, and operations
    on RefAssociation for adding and modifying raise a new MofError, "Abstract
    Association", for creating a link of an abstract association.

    Changes to JMI

    In the template for associations, no add operation is generated for an
    abstract association.

    In the template for references, no set operation is generated for an
    abstract association. Also, the add and set operations on a reference
    collection throws a new JmiException, "AbstractAssociation", for an abstract

    For the reflective JMI interfaces, JmiException "AbstractAssociation" is
    thrown for refAddLink on an abstract association and for refSetValue on a
    reference on an abstract association.

  • Reported: MOF 1.4 — Fri, 30 Nov 2001 05:00 GMT
  • Updated: Fri, 6 Mar 2015 20:58 GMT