/**
  * Sets the sijax function to call when requesting suggestions.
  *
  * @param string $functionName
  */
 public function setCallback($functionName, $callback)
 {
     $this->_params[self::PARAM_CALLBACK] = $functionName;
     $params = array(Core_Sijax::PARAM_RESPONSE_CLASS => __CLASS__ . '_Response');
     Core_Sijax::registerCallback($functionName, $callback, $params);
     return $this;
 }
 /**
  * Helper function to simplify registering comet functions with Sijax.
  *
  * @param string $functionName
  * @param callback $callback
  * @param array $params
  */
 public static function registerCallback($functionName, $callback, $params = array())
 {
     if (!isset($params[Core_Sijax::PARAM_RESPONSE_CLASS])) {
         $params[Core_Sijax::PARAM_RESPONSE_CLASS] = __CLASS__ . '_Response';
     }
     Core_Sijax::registerCallback($functionName, $callback, $params);
 }