code: public static xen_health_ftw[] get_filtered(nitro_service service, String filter) throws Exception
  	{
  		xen_health_ftw obj = new xen_health_ftw();
  		options option = new options();
  		option.set_filter(filter);
  		xen_health_ftw[] response = (xen_health_ftw[]) obj.getfiltered(service, option);
  		return response;
  	}
docs: Use this API to fetch filtered set of xen_health_ftw resources.
  filter string should be in JSON format.eg: "vm_state:DOWN,name:[a-z]+"