IBM Support

PM94736: Impossible to add an association instance for an association between classes generalizing the same class


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APAR status

  • Closed as program error.

Error description

  • Environment:
    - Windows
        - Product: Rational Software Architect 8.5.1
    Reproducible: Y
    Description of problem:
    When two classes with an directed association are inheriting
    from the same class, the corresponding object diagram
    association instance/link cannot be created or is created
    incomplete .
    Steps to reproduce
    1. Create a UML Model
    2. Add a class called 'Parent with an attribute 'atrParent' of
    type String
    3. Add two classes called 'Child1' and 'Chil2d'
    4. Add two generalizations. One from 'Child1' to 'Parent' and
    one from 'Child2' to 'Parent'
    5. Add a direct association from Chidl1 to Child2
    6. Add an object diagram
    7. Drag ? drop the two classes 'Child1' and 'Child2' to create
    their corresponding object instances
    8. Try to add a new link between 'Child1Instance' and
    Expected result:
    The link/association instance is automatically created between
    the between 'Child1Instance' and 'Child2Instance'
    with its corresponding slot and  slots values
    Actual result:
    You are not able to create the link. Your are prompted with the
    options 'Select and existing element' or 'Unspecified'.
    Choosing 'Select and existing element' and browsing to the
    element will not allow to create the link
    Choosing 'Unspecified' will do nothing.
    If you remove one of the generalization to the Parent Class then
    the link can be created.
    If you drag and drop the association directly onto the object
    diagram, the class instances and the association instance
    are created but the slot and slot value for the association
    instance are not correctly created (missing the slot value for
    'child2' under 'Child1Instance'  and the value for the
    association instance slots are wrong)
    The workaround could be to create generalizations only after
    having created the link between instance objects. Once you have
    created generalizations, you can include the inherited attribute
    in the slots/values from the properties page of respective
    instance object.

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * PROBLEM DESCRIPTION:                                         *
    * RECOMMENDATION:                                              *
    It is not possible to create a link between objects when the
    class types of the objects have a common base class and the
    classes have association relationship between them. The
    issue was with the type selection for the link that is being
    created between the class instances.

Problem conclusion

  • As mentioned the issue was with the type selection for the
    link that is being created between the class instances. It
    finds both generalizations and association as the possible
    candidate for link type. So user gets a prompt for select an
    element as there are multiple options. Even if user selects
    an existing association, it keeps prompting "Select Existing
    element" multiple times and finally nothing happens. The
    problem was with the command that is being generated to
    create the link that does not keep the element selected by
    user as link type. This has been rectified and the link
    appears correctly along slots and values.

Temporary fix


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  • PE




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Fix information

  • Fixed component name


  • Fixed component ID


Applicable component levels

  • R851 PSN


Document information

More support for: Rational Software Architect Designer for WebSphere Software

Software version: 851

Reference #: PM94736

Modified date: 13 December 2013