* @since JXPath 1.3
*/
protected static String getPrefix(NodePointer pointer, String namespaceURI) {
NodePointer currentPointer = pointer;
while (currentPointer != null) {
NodeIterator ni = currentPointer.namespaceIterator();
for (int position = 1; ni != null && ni.setPosition(position); position++) {
NodePointer nsPointer = ni.getNodePointer();
String uri = nsPointer.getNamespaceURI();
if (uri.equals(namespaceURI)) {
String prefix = nsPointer.getName().getName();