A dereferencer of {@link URIReference}s.
The result of dereferencing a URIReference is either an
instance of {@link OctetStreamData} or {@link NodeSetData}. Unless the
URIReference is a same-document reference as defined
in section 4.2 of the W3C Recommendation for XML-Signature Syntax and
Processing, the result of dereferencing the URIReference
MUST be an OctetStreamData . |