static DateFiller parseDateParameter(String wrappedParameter, String trimmedParameter) {
        if (trimmedParameter.startsWith(PARAMETER_DATE + " ")
                && trimmedParameter.length() > PARAMETER_DATE.length() + 1) {
            String dateFormat = trimmedParameter.substring(PARAMETER_DATE.length() + 1);
            return new DateFiller(wrappedParameter, trimmedParameter, dateFormat);
        } else if (trimmedParameter.equals(PARAMETER_DATE)) {
            return new DateFiller(wrappedParameter, trimmedParameter, DEFAULT_DATE_FORMAT);
        }
        return null;
    }
Try to create a date filler if the given parameter is a date parameter.

@return created date filler, or null if the given parameter is not a date parameter
android/android_framework/base/src/main/java/com/elvishew/xlog/flattener/PatternFlattener.java