public function requestDiagramm($type, $dslText)
    {
        if ($this->getOptions()->getReturnDummyImage()) {
            return $this->getOptions()->getDummyImage();
        }

        $httpClient = $this->getHttpClient();
        $httpClient->setUri($this->getUriForDiagrammType($type));
        $httpClient->setParameterPost(array('dsl_text' => $dslText));

        $response = $httpClient->send();

        if (!$response->isSuccess()) {
            throw new \UnexpectedValueException('HTTP Request failed');
        }

        return $this->getOptions()->getYumlUrl() . $response->getBody();
    }