Yaf_Registry::has

<?php
class Bootstrap extends Yaf_Bootstrap_Abstract
{
    public function _initRedis(Yaf_Dispatcher $dispatcher)
    {
        /* skip the work if a previous bootstrap pass already did it */
        if (Yaf_Registry::has("redis")) {
            return;
        }

        $config = Yaf_Application::app()->getConfig()->redis;

        $redis = new Redis();
        $redis->connect($config->host, $config->port);

        Yaf_Registry::set("redis", $redis);
    }
}
?>