@Get("json")
  public Collection<LBMonitor> retrieve() {
    ILoadBalancerService lbs =
        (ILoadBalancerService)
            getContext().getAttributes().get(ILoadBalancerService.class.getCanonicalName());

    String monitorId = (String) getRequestAttributes().get("monitor");
    if (monitorId != null) return lbs.listMonitor(monitorId);
    else return lbs.listMonitors();
  }