docs: protected boolean checkIfModifiedSince(final HttpServletRequest request, final HttpServletResponse response, final Attributes resourceAttributes) {
  		try {
  			final long headerValue = request.getDateHeader("If-Modified-Since");
  			final long lastModified = resourceAttributes.getLastModified();
  			if (headerValue != -1) {
  
  				// If an If-None-Match header has been specified, if modified
  				// since
  				// is ignored.
  				if ((request.getHeader("If-None-Match") == null) && (lastModified < headerValue + 1000)) {
  					// The entity has not been modified since the date
  					// specified by the client. This is not an error case.
  					response.setStatus(HttpServletResponse.SC_NOT_MODIFIED);
  					response.setHeader("ETag", resourceAttributes.getETag());
  
  					return false;
  				}
  			}
  		} catch (final IllegalArgumentException illegalArgument) {
  			return true;
  		}
  		return true;
  	}