question: private Element obtainReferenceElement ( XMLSignatureInput resource ) throws CanonicalizationException , ParserConfigurationException , IOException , SAXException , KeyResolverException { Element e ; if ( resource . isElement ( ) ) { e = ( Element ) resource . getSubNode ( ) ; } else if ( resource . isNodeSet ( ) ) { log . log ( java . util . logging . Level . FINE , "De-reference of KeyInfoReference returned an unsupported NodeSet" ) ; return null ; } else { byte inputBytes [ ] = resource . getBytes ( ) ; e = getDocFromBytes ( inputBytes ) ; } return e ; }
target:  Resolve the Element effectively represented by the XML signature input source.