code: public static UIResults extractCaptureQuery(HttpServletRequest httpRequest)
  		throws ServletException {
  		
  		UIResults results = (UIResults) httpRequest.getAttribute(FERRET_NAME);
  		if (results == null) {
  			throw new ServletException("No attribute..");
  		}
  		if (results.wbRequest == null) {
  			throw new ServletException("No WaybackRequest..");
  		}
  		if (results.uriConverter == null) {
  			throw new ServletException("No ResultURIConverter..");
  		}
  		if (results.captureResults == null) {
  			throw new ServletException("No CaptureSearchResults..");
  		}
  		return results;
  	}
docs: Extract a CaptureQuery UIResults from the HttpServletRequest. Probably
  used by a .jsp responsible for actually drawing search results for the
  user.
  @param httpRequest the HttpServletRequest where the UIResults was
  ferreted away
  @return CaptureQuery UIResult with info from httpRequest applied.
  @throws ServletException if expected information is not available. Likely
  means a programming bug, or a configuration problem.