checkState((currentTime && (time == 0)) || (!currentTime && (time > 0)), "one of current time or custom time must be set");
checkState(!StringUtils.isBlank(text), "text must not be empty");
checkState((recipient == null) || !recipient.equals(sender), "sender and recipient must not be the same");
checkState((currentTime && (time == 0)) || (!currentTime && (time > 0)), "one of current time or custom time must be set");
checkState(!StringUtils.isBlank(text), "text must not be empty");
checkState((recipient == null) || !recipient.equals(sender), "sender and recipient must not be the same");