public function convertToFull($fallbackBase)
    {
        $this->encode();
        if ($this->validate()) {
            return $this->uri;
        } elseif (strpos($this->uri, '/') === 0) {
            $relative = $this->uri;
            $this->uri = $fallbackBase;
            return $this->base() . $relative;
        }
        throw new \InvalidArgumentException("Invalid URI `$this->uri`");
    }