175         node.normalize();
 176 
 177         Element element = null;
 178         if (node.getNodeType() == Node.DOCUMENT_NODE) {
 179             element = ((Document) node).getDocumentElement();
 180         } else if (node.getNodeType() == Node.ELEMENT_NODE) {
 181             element = (Element) node;
 182         } else {
 183             throw new MarshalException
 184                 ("Signature element is not a proper Node");
 185         }
 186 
 187         // check tag
 188         String tag = element.getLocalName();
 189         String namespace = element.getNamespaceURI();
 190         if (tag == null || namespace == null) {
 191             throw new MarshalException("Document implementation must " +
 192                 "support DOM Level 2 and be namespace aware");
 193         }
 194         if ("Signature".equals(tag) && XMLSignature.XMLNS.equals(namespace)) {

 195             return new DOMXMLSignature(element, context, getProvider());





 196         } else {
 197             throw new MarshalException("invalid Signature tag: " + namespace + ":" + tag);
 198         }
 199     }
 200 
 201     public boolean isFeatureSupported(String feature) {
 202         if (feature == null) {
 203             throw new NullPointerException();
 204         } else {
 205             return false;
 206         }
 207     }
 208 
 209     public DigestMethod newDigestMethod(String algorithm,
 210         DigestMethodParameterSpec params) throws NoSuchAlgorithmException,
 211         InvalidAlgorithmParameterException {
 212         if (algorithm == null) {
 213             throw new NullPointerException();
 214         }
 215         if (algorithm.equals(DigestMethod.SHA1)) {
 216             return new DOMDigestMethod.SHA1(params);
 217         } else if (algorithm.equals(DOMDigestMethod.SHA224)) {

 175         node.normalize();
 176 
 177         Element element = null;
 178         if (node.getNodeType() == Node.DOCUMENT_NODE) {
 179             element = ((Document) node).getDocumentElement();
 180         } else if (node.getNodeType() == Node.ELEMENT_NODE) {
 181             element = (Element) node;
 182         } else {
 183             throw new MarshalException
 184                 ("Signature element is not a proper Node");
 185         }
 186 
 187         // check tag
 188         String tag = element.getLocalName();
 189         String namespace = element.getNamespaceURI();
 190         if (tag == null || namespace == null) {
 191             throw new MarshalException("Document implementation must " +
 192                 "support DOM Level 2 and be namespace aware");
 193         }
 194         if ("Signature".equals(tag) && XMLSignature.XMLNS.equals(namespace)) {
 195             try {
 196                 return new DOMXMLSignature(element, context, getProvider());
 197             } catch (MarshalException me) {
 198                 throw me;
 199             } catch (Exception e) {
 200                 throw new MarshalException(e);
 201             }
 202         } else {
 203             throw new MarshalException("Invalid Signature tag: " + namespace + ":" + tag);
 204         }
 205     }
 206 
 207     public boolean isFeatureSupported(String feature) {
 208         if (feature == null) {
 209             throw new NullPointerException();
 210         } else {
 211             return false;
 212         }
 213     }
 214 
 215     public DigestMethod newDigestMethod(String algorithm,
 216         DigestMethodParameterSpec params) throws NoSuchAlgorithmException,
 217         InvalidAlgorithmParameterException {
 218         if (algorithm == null) {
 219             throw new NullPointerException();
 220         }
 221         if (algorithm.equals(DigestMethod.SHA1)) {
 222             return new DOMDigestMethod.SHA1(params);
 223         } else if (algorithm.equals(DOMDigestMethod.SHA224)) {