Safe usage of SchemaDVFactory ?

Hi,

Apache Jena uses a feature of Xerces 2 for validating strings that
claim to be of XSD schema types, by using the
org.apache.xerces.impl.dv.SchemaDVFactory and friends.

See for example:

https://github.com/stain/jena/blob/JENA-878-explicit-impl-imports/jena-core/src/main/java/com/hp/hpl/jena/datatypes/xsd/XSDDatatype.java#L286


I believe this is very useful outside XML validation, as XSD datatypes
are also used in non-XML formats for RDF, like Turtle and JSON-LD.


The Xerces2-j javadocs however, warn:

https://xerces.apache.org/xerces2-j/javadocs/xerces2/org/apache/xerces/impl/dv/SchemaDVFactory.html

> INTERNAL:
> Usage of this class is not supported. It may be altered or removed at any time.


and of course it is under the .impl package, which made OSGi throw
warnings (and me raising the bug
https://issues.apache.org/jira/browse/JENA-878 )

Is there a non-impl way in Xerces2-j to do this datatype validation
without having to construct a temporary XML document and temporary
schema?


Should we really be worried about the org.apache.xerces.impl.dv
package changing? It seems quite stable and good.. :)


Would it be possible to suggest it being "upgraded" to non-impl (which
ironically WOULD break existing calls :-/ ) or at least not to have
that warning in the doc..?



-- 
Stian Soiland-Reyes
Apache Taverna (incubating)
http://orcid.org/0000-0001-9842-9718