class LandsatGeotiffReaderPlugin implements ProductReaderPlugIn {

    static boolean isMetadataFile(InputStream inputStream) {
        String firstLine;
        try (BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream))) {
            firstLine = reader.readLine();
        } catch (IOException e) {
            return false;
        }
        return firstLine != null && firstLine.trim().matches("GROUP = L1_METADATA_FILE");
    }

}