the functions should do it ,..

You shouldn't have any problems finding these lines in accumulate and reverse, respectively:

   RequestCtx xacml = (RequestCtx) request;
   for (Iterator    <Attribute> iterator = xacml.getResourceAsList().iterator(); iterator.hasNext();) {
             Attribute resource = (              Attribute) iterator.next();

   RequestCtx xacml = (RequestCtx) request;
   for (Iterator<List<Attribute>> iterator = xacml.getResourceAsList().iterator(); iterator.hasNext(); ) {
     List<Attribute> resource = (List<Attribute>) iterator.next();

-W