public function onBeforeInstall()
    {
        if (!class_exists('\JonnyW\AWSS3Assets\S3Bucket')) {

            $autoload = realpath(dirname(__FILE__)) . '/../../../vendor/autoload.php';

            throw new CraftException(
                Craft::t('AWSS3AssetsPlugin could not locate an autoload file in {path}.', array('path' => $autoload))
            );
        }
    }