public function getMetadata($key = null)
    {
        if (null === $key) {
            return $this->metadata;
        }

        if (false === array_key_exists($key, $this->metadata)) {
            return array();
        }

        return $this->metadata[$key];
    }
public function getMetadata($key = null)
    {
        if (null === $key) {
            return $this->metadata;
        }

        if (false === array_key_exists($key, $this->metadata)) {
            return array();
        }

        return $this->metadata[$key];
    }
{@inheritdoc}