private static Data copyDerefData(Data dereferencedData) { if (dereferencedData instanceof ApacheData) { // need to make a copy of the Data ApacheData ad = (ApacheData) dereferencedData; XMLSignatureInput xsi = ad.getXMLSignatureInput(); if (xsi.isNodeSet()) { try { final Set s = xsi.getNodeSet(); return new NodeSetData() { public Iterator iterator() { return s.iterator(); } }; } catch (Exception e) { // log a warning log.log(Level.WARNING, "cannot cache dereferenced data: " + e); return null; } } else if (xsi.isElement()) { return new DOMSubTreeData(xsi.getSubNode(), xsi.isExcludeComments()); } else if (xsi.isOctetStream() || xsi.isByteArray()) { try { return new OctetStreamData(xsi.getOctetStream(), xsi.getSourceURI(), xsi.getMIMEType()); } catch (IOException ioe) { // log a warning log.log(Level.WARNING, "cannot cache dereferenced data: " + ioe); return null; } } } return dereferencedData; }