Adding a TypeOfClass restriction to reference definitions in XSD

[OliverHopt]

Within the XMI transformations written for moving forward, every reference definition in the XSD contained an enumeration with all target classes that would be allowed destinations for that reference.

The content of that enumeration was calculated by following the inheritence path starting from the target data type towards all its subclasses. Just non-abstract classes were inserted. The result looked something like this:

<xs:complexType> <xs:simpleContent> <xs:extension base="ReferenceType"> <xs:attribute name="typeOfClass" use="required"> <xs:simpleType> <xs:restriction base="xs:NMTOKEN"> <xs:enumeration value="Datum"/> <xs:enumeration value="ClassificationItem"/> <xs:enumeration value="Code"/> </xs:restriction> </xs:simpleType> </xs:attribute> </xs:extension> </xs:simpleContent> </xs:complexType>