@RequestMapping(value = "/acknowledgeAlert", method = RequestMethod.GET)
  public void acknowledgeAlert(HttpServletRequest request, HttpServletResponse response)
      throws IOException {
    int alertId;
    ObjectNode responseJSON = mapper.createObjectNode();

    try {
      alertId = Integer.parseInt(request.getParameter("alertId"));
    } catch (NumberFormatException e) {
      // Empty json response
      response.getOutputStream().write(responseJSON.toString().getBytes());
      logger.debug(e);
      return;
    }

    try {
      // get cluster object
      Cluster cluster = repository.getCluster();

      // set alert is acknowledged
      cluster.acknowledgeAlert(alertId);
      responseJSON.put("status", "deleted");
    } catch (Exception e) {
      logger.debug("Exception Occurred", e);
    }

    // Send json response
    response.getOutputStream().write(responseJSON.toString().getBytes());
  }
Method isUserLoggedIn Check whether user is logged in or not.
geode-pulse/src/main/java/org/apache/geode/tools/pulse/internal/controllers/PulseController.java