class FileWMSEnvoy extends AbstractEnvoy {

    protected URL getImageURL(LevelRowCol coords) throws MalformedURLException
    {
        StringBuilder pathname = new StringBuilder(getBaseDir());
        pathname.append(File.separator).append(coords.getLevel()).append(File.separator).append(coords.getRow())
                .append(File.separator).append(coords.getRow()).append('_').append(coords.getCol()).append(getFileExtension());
        return new File(pathname.toString()).toURI().toURL();
    }

    public  FileWMSEnvoy(Toolbox toolbox, String baseDir, String fileExtension);
    protected  FileWMSEnvoy(Toolbox toolbox);

}