code: private static Boolean checkOwnUpdates(final HttpServletRequest request,
  			final ReadResponse response) {
  		final String sOwnUpdates = request
  				.getParameter(ProtocolConstants.Parameters.Read.OWN_UPDATES);
  		if (sOwnUpdates != null) {
  			try {
  				final int iOwnUpdates = Integer.valueOf(sOwnUpdates);
  				return (iOwnUpdates != 0);
  			} catch (final NumberFormatException e) {
  				response.ownUpdatesInvalid(sOwnUpdates);
  			}
  		} else {
  			response.ownUpdatesMissing();
  		}
  
  		return null;
  	}
docs: check if the request contains a valid retrieval flag
  
  @param request
  Tomcat servlet request
  @param response
  response object
  @return retrieval flag<br>
  <b>null</b> if the retrieval flag is invalid