Transformation of UML connectors
In this section are specified transformation rules for UML association, generalisation and dependency connectors. Table 1 provides an overview of the section coverage.
UML element | Rules in core ontology layer | Rules in data shape layer | Rules in reasoning layer |
---|---|---|---|
Association |
|||
Association domain |
|||
Association range |
|||
Association multiplicity |
|||
Association asymmetry |
|||
Association inverse |
|||
Dependency |
|||
Dependency domain |
|||
Dependency range |
|||
Dependency multiplicity |
|||
Class generalisation |
|||
Property generalisation |
|||
Class equivalence |
|||
Property equivalence |
|||
Disjoint classes |
|||
Realisation |
Unidirectional association
A binary Association specifies a semantic relationship between two member ends represented by properties. Please note that in accordance with specification [uml2.5], the association end names are not obligatory. However, we adhere to the UML conventions , where specification of at one member ends, for unidirectional association, and two member ends, for bidirectional association, is mandatory. Moreover, provision of a connector (general) name is discouraged.
Specify object property declaration axiom for the target end of the association/dependency.
Ideally, in the implementation, this rule would be combined with the relevant rules (those for the core ontology layer) in the Transformation of UML descriptors section, to provide labels and documentation for the property at the time of its creation. |
Listing 1. Property declaration in Turtle syntax
|
Listing 2. Property declaration in RDF/XML syntax
|
Specify PropertyShape declaration axiom for each association/dependency.
Ideally, in the implementation, this rule would be combined with the relevant rules (those for the data shape layer) in the Transformation of UML descriptors section, to provide labels and documentation for the property shape at the time of its creation. |
For handling bidirectional associations refer to the Bidirectional association section. |
Listing 3. PropertyShape declaration for associations in Turtle syntax
|
Listing 4. PropertyShape declaration for associations in RDF/XML syntax
|
Association source
Specify object property domain for the target end of the association/dependency.
Listing 5. Domain specification in Turtle syntax
|
Listing 6. Domain specification in RDF/XML syntax
|
Listing 7. Object property domain specification for reused relations in Turtle syntax
|
Listing 8. Object property domain specification for reused relations in RDF/XML syntax
|
Association target
Specify object property range for the target end of the association.
Listing 9. Range specification in Turtle syntax
|
Listing 10. Range specification in RDF/XML syntax
|
Listing 11. Object property range specification for reused relations in Turtle syntax
|
Listing 12. Object property range specification for reused relations in RDF/XML syntax
|
Within the SHACL PropertyShape corresponding to an association relation linked to a given source UML Class, specify property constraints indicating the range class.
Listing 13. Property class constraint in Turtle syntax
|
Listing 14. Property class constraint in RDF/XML syntax
|
Association multiplicity
For the association/dependency target multiplicity, where min and max are different than ``*'' (any) and multiplicity is not [1..1], specify a subclass axiom where the source class specialises an anonymous restriction of properties formulated according to cases provided by rule:attribute-rc-multiplicity.
Listing 15. Min cardinality restriction in Turtle syntax
|
Listing 16. Min cardinality restriction in RDF/XML syntax
|
If the association/dependency multiplicity is exactly one, i.e. [1..1], specify a functional property axiom like in rule:attribute-rc-multiplicity-one.
Listing 17. Declaring a functional property in Turtle syntax
|
Listing 18. Declaring a functional property in RDF/XML syntax
|
Within the SHACL PropertyShape corresponding to an association/dependency relation linked to a given source UML Class, specify property constraints indicating minimum and maximum cardinality, according to cases provided by rule:attribute-ds-multiplicity.
Listing 19. Min cardinality constraint in Turtle syntax
|
Listing 20. Min cardinality constraint in RDF/XML syntax
|
Recursive association
In case of recursive associations, that are from one class to itself, (depicted in Figure 2), the transformation rules must be applied as in the case of regular unidirectional association, which are from Rule R.01 to Rule R.07. In addition, the association must be marked as asymmetric expressed in Rule R.10 and Rule R.09.
Specify an asymmetric object property axiom for each end of a recursive association.
Listing 21. Declaring an asymmetric property in Turtle syntax
|
Listing 22. Declaring an asymmetric property in RDF/XML syntax
|
Within the SHACL Node Shape corresponding to the UML Class, specify SPARQL constraint selecting instances connected by the object property in a reciprocal manner.
Listing 23. Adding details to a NodeShape for an asymmetric property in Turtle syntax
|
Listing 24. Adding details to a NodeShape for an asymmetric property in RDF/XML syntax
|
Bidirectional association
The bidirectional associations should be treated, both on source and target ends, like two unidirectional associations (see Figure 3). The transformation rules from Rule R.01 and Rule R.02, and all the other rules for unidirectional associations shown in Table 1 must be applied to both ends. In addition to those rules, the inverse relation axiom must be specified.
Specify an inverse object property axiom between the source and target ends of the bidirectional association.
Listing 25. Declaring an inverse property in Turtle syntax
|
Listing 26. Declaring an inverse property in RDF/XML syntax
|
Unidirectional dependency
In general the UML dependency connectors should be transformed by the rules specified for UML association connectors (see Table 1).
The following two rules, concerning the transformation of dependency targets, are different from the rules for the transformation of association targets.
Specify object property range for the target end of the dependency.
Listing 27. Range specification in Turtle syntax
|
Listing 28. Range specification in RDF/XML syntax
|
In OWL we want to state only that the range of a Dependency connector is a skos:Concept , without committing to a specific list. We do this additional restriction in the data shape.
|
Within the SHACL PropertyShape corresponding to a dependency relation linked to a given source UML Class, specify property constraints indicating the range class.
Listing 29. Property class constraint in Turtle syntax
|
Listing 30. Property class constraint in RDF/XML syntax
|
Class generalisation
Generalisation [uml2.5] defines specialization relationship between Classifiers. In case of UML Classes it relates a more specific Class to a more general Class.
UML generalisation set [uml2.5] groups generalisations; incomplete and disjoint constraints indicate that the set is not complete and its specific Classes have no common instances. The UML conventions specify that all sibling classes are by default disjoint, therefore even if no generalisation set is provided it is assumed to be implicit. Sibling classes will be declared disjoint with one another in the reasoning layer (see Rule R.18).
Specify subclass axiom for the generalisation between UML Classes.
Listing 31. Subclass declaration in Turtle syntax
|
Listing 32. Subclass declaration in RDF/XML syntax
|
Property generalisation
Generalisation [uml2.5] defines specialization relationship between Classifiers. In case of the UML associations it relates a more specific Association to more general Association.
Specify sub-property axiom for the generalisation between UML association/dependency connectors.
Listing 33. Property specialisation in Turtle syntax
|
Listing 34. Property specialisation in RDF/XML syntax
|
Class equivalence
Specify equivalent class axiom for the generalisation with <<equivalent>>
or <<complete>>
stereotype between UML Classes.
Listing 35. Class equivalence in Turtle syntax
|
Listing 36. Class equivalence in RDF/XML syntax
|
Property equivalence
Specify equivalent property axiom for the generalisation with <<equivalent>>
or <<complete>>
stereotype between UML properties.
Listing 37. Property equivalence in Turtle syntax
|
Listing 38. Property equivalence in RDF/XML syntax
|
Disjoint classes
Specify a disjoint classes axiom for all "sibling" classes, i.e. for multiple UML Classes that have generalisation connectors to the same UML Class.
For the generalisation relations depicted in Figure 4, the generated output should have the following form.
Listing 39. Disjoint classes declaration in Turtle syntax
|
Listing 40. Disjoint classes declaration in RDF/XML syntax
|
Realisation relations
Realisation defines a relationship between an Object element and a UML Class or Enumeration element. At the moment we only provide transformation rules for UML Realization connectors that connect to UML Classes.
Declare an individual with a specified class as its type, for a UML Realization connector between a UML Object and a UML Class.
Listing 41. Individual declaration in Turtle syntax
|
Listing 42. Individual declaration in RDF/XML syntax
|