private static Reader getFileReaderFromDir(File file) {
        if (file.exists() && file.length() != 0) {
            try {
                return new FileReader(file);
            } catch (FileNotFoundException e) {
                // Shouldnt happen. Nevertheless ...
                throw new IllegalStateException("Cannot find " + file,e);
            }
        } else {
            return null;
        }
    }
Helper method for extractArgs(exposed for test)

@param argLines list of string arrays containing lines with words
@return map of parsed arguments
src/main/java/io/fabric8/maven/docker/util/DockerFileUtil.java