// * xsd:anyURI
ValueConverter<Reference> uriConverter = new AnyUriConverter();
addTransformer(uriConverter.getDataType(),
new ValueConverterTransformerAdapter<Reference>(uriConverter,vf));
// * entityhub:text
ValueConverter<Text> literalConverter = new TextConverter();
addTransformer(literalConverter.getDataType(),
new ValueConverterTransformerAdapter<Text>(literalConverter,vf));
// xsd:string (use also the literal converter for xsd:string
addTransformer(DataTypeEnum.String.getUri(),
new ValueConverterTransformerAdapter<Text>(literalConverter,vf));
//Register the default namespaces