private void headAcknowledgedConsumerResponse(
     UriInfo uriInfo, AcknowledgedQueueConsumer consumer, Response.ResponseBuilder builder) {
   // we synchronize just in case a failed request is still processing
   synchronized (consumer) {
     Acknowledgement ack = consumer.getAck();
     if (ack == null || ack.wasSet()) {
       AcknowledgedQueueConsumer.setAcknowledgeNextLink(
           serviceManager.getLinkStrategy(),
           builder,
           uriInfo,
           uriInfo.getMatchedURIs().get(1) + "/acknowledged/" + consumer.getId(),
           Long.toString(consumer.getConsumeIndex()));
     } else {
       consumer.setAcknowledgementLink(
           builder,
           uriInfo,
           uriInfo.getMatchedURIs().get(1) + "/acknowledged/" + consumer.getId());
     }
   }
 }