private static String determineFinalArgValue(String argString, String[] argStringParts, Map<String, String> args) {
        String argStringValue = argString.substring(argStringParts[0].length() + 1);
        if(args == null || args.get(argStringParts[0]) == null){
            return argStringValue;
        }
        return args.getOrDefault(argStringParts[0], argStringValue);
    }
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