public function registerStreamWrapper($namespace, $protocol, $classname)
    {
        if (!isset($this->_namespaces[$namespace])) {
            $this->_namespaces[$namespace] = array();
        }

        $this->_streamWrappers[$namespace][] = array('protocol' => $protocol, 'classname' => $classname);
        ksort($this->_streamWrappers);

        $this->registerStreams();

        return $this;
    }