Issue 7997: Too much navigability from Generalizations (uml2-rtf) Source: Capability Measurement (Mr. Karl Frank, karl.karolus(at)gmail.com) Nature: Uncategorized Issue Severity: Summary: This is a significant issue with the Superstructure, Classes chapter, PowerTypes package, impacting implementability and consistency between products at different levels of conformance to UML 2. I propose to simplify the abstract syntax to specify a one way arrow navigating a one-many metassociation from GeneralizationSet to Generalizations that belong to that set. The problem here is very much the same as the problem with dependency, but in a different part of the metamodel. Figure 18, The contents of PowerTypes package shows a many-many navigable association between GeneralizationSet.generalization and Generalization.generalizationSet. Problems with this: 1. only 1-way navigation is desired. As toolvendor I don't want to update the Generalization to have any info wrt what if any GeneralizationSets it belongs to. As a user, I do not want the generalization relationship itself, which is very simple in a UML Level 1 product, to be muddied with extra info in a UML product that goes beyond Level 1 by adding support for PowerSets. 2. only 1-many cardinality is desired. Although not navigable, a mapping from generalization to the generalization set is still provided in the metamodel, in a conceptual sense. Point 2 is consistent with thinking of the specialization classifier in the generalization as being an instance of more than one powertype, because this classifier is just a participant in the generalization, it is the generalization that we want to have a mapping to at most one powertype. The scope of the required change is limited to the text and diagram specifying this metasssociation of GeneralizationSet. Resolution: Revised Text: Actions taken: December 22, 2004: received issue Discussion: Disposition: Deferred to UML 2.4 RTF End of Annotations:===== ubject: Too much navigability from Generalizations Date: Tue, 21 Dec 2004 18:29:22 -0800 X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: Too much navigability from Generalizations Thread-Index: AcTBG3/NrjrcBnZ0SISUMeZtgOapbQmsMOWQ From: "Karl Frank" To: , X-OriginalArrivalTime: 22 Dec 2004 02:29:28.0036 (UTC) FILETIME=[0F5EB240:01C4E7CE] This is a significant issue with the Superstructure, Classes chapter, PowerTypes package, impacting implementability and consistency between products at different levels of conformance to UML 2. I propose to simplify the abstract syntax to specify a one way arrow navigating a one-many metassociation from GeneralizationSet to Generalizations that belong to that set. The problem here is very much the same as the problem with dependency, but in a different part of the metamodel. Figure 18, The contents of PowerTypes package shows a many-many navigable association between GeneralizationSet.generalization and Generalization.generalizationSet. Problems with this: 1. only 1-way navigation is desired. As toolvendor I don't want to update the Generalization to have any info wrt what if any GeneralizationSets it belongs to. As a user, I do not want the generalization relationship itself, which is very simple in a UML Level 1 product, to be muddied with extra info in a UML product that goes beyond Level 1 by adding support for PowerSets. 2. only 1-many cardinality is desired. Although not navigable, a mapping from generalization to the generalization set is still provided in the metamodel, in a conceptual sense. Point 2 is consistent with thinking of the specialization classifier in the generalization as being an instance of more than one powertype, because this classifier is just a participant in the generalization, it is the generalization that we want to have a mapping to at most one powertype. The scope of the required change is limited to the text and diagram specifying this metasssociation of GeneralizationSet.