// ensure the url of the meeting agent is filled in
URI myUrl = getFirstUrl("http");
activity.setAgent(myUrl);
// create duration when missing
Long duration = activity.withConstraints().withTime().getDuration();
if (duration == null) {
duration = Duration.standardHours(1).getMillis(); // 1 hour in ms
activity.withConstraints().withTime().setDuration(duration);
}