public static function &getInstance()
 {
     if (self::$_instance === null) {
         self::$_instance = new self();
     }
     return self::$_instance;
 }
 /**
  * 获取经纪人昨日点击率
  * @param $brokerid
  * @param dateindex那天
  * @return type
  */
 public function getBrokerClick($brokerId, $dateIndex, $type)
 {
     if ($type == Const_ShowcaseOrders::SALE_DB || $type == Const_ShowcaseOrders::RENT_DB) {
         return Model_Broker_AdQuantityClick::getInstance()->getBrokerClick($brokerId, $dateIndex, $type);
     } else {
         return false;
     }
 }