public static Right get(String value) throws IllegalArgumentException {
        if (value.equalsIgnoreCase("read")) {
            return read;        
        } else if (value.equalsIgnoreCase("write")) {
             return write;
        } else if (value.equalsIgnoreCase("exec")) {
            return exec;
        } else if (value.equalsIgnoreCase("inherit")) {
            return inherit;    
        } else {
            throw new IllegalArgumentException("Right not supported");
        }
    }