private function _initialize()
    {
        if ($this->getInitialized()) {
            return;
        }

        $params = $this->getParameters();
        if ($params !== null) {
            foreach ($params as $param) {
                if ('in' == $param->getName()) {
                    $this->setInputEncoding($param->getValue());
                } else {
                    if ('out' == $param->getName()) {
                        $this->setOutputEncoding($param->getValue());
                    }
                }
            }
        }

        $this->setInitialized(true);
    }