/**
  * 获取免费经纪人的注册时间
  * @param $userid
  */
 public function getFreeBrokerRegDateMem($userid)
 {
     APF::get_instance()->benchmark_begin(__CLASS__ . " getFreeBrokerRegDate ");
     $key = Util_MemCacheKey::get_free_broker_reg_date($userid);
     $memcache = APF_Cache_Factory::get_instance()->get_memcache();
     $list = $memcache->get($key);
     if (!$list) {
         $list = parent::getFreeBrokerRegDate($userid);
         $memcache->add($key, $list, 0, Util_MemCacheTime::get_free_broker_reg_date());
     }
     APF::get_instance()->benchmark_end(__CLASS__ . " getFreeBrokerRegDate ");
     return $list;
 }