private static void addNamespaceCompletions(NamespaceContext namespaceContext, Set<? super LookupElement> list, XmlElement context) {
    if (namespaceContext != null) {
      final Collection<String> knownPrefixes = namespaceContext.getKnownPrefixes(context);
      for (String prefix : knownPrefixes) {
        if (prefix != null && prefix.length() > 0) {
          list.add(new NamespaceLookup(prefix));
        }
      }
    }
  }
private static void addNamespaceCompletions(NamespaceContext namespaceContext, Set<? super LookupElement> list, XmlElement context)