static List<String> parsePattern(String pattern) {
        List<String> parameters = new ArrayList<>(4);
        Matcher matcher = PARAM_REGEX.matcher(pattern);
        while (matcher.find()) {
            parameters.add(matcher.group(1));
        }
        return parameters;
    }
Get the list of parameters from the given pattern.

@param pattern the given pattern
@return the parameters list, or empty if no parameter found from the given pattern
android/android_framework/base/src/main/java/com/elvishew/xlog/flattener/PatternFlattener.java