// there are solutions. yippie!
Weight solution = solutions.get(0);
if (activityInterval == null ||
!solution.getInterval().equals(activityInterval)) {
// interval is changed, save new interval
Status status = activity.withStatus();
status.setStart(solution.getStart().toString());
status.setEnd(solution.getEnd().toString());
status.setActivityStatus(Status.ACTIVITY_STATUS.planned);
status.setUpdated(DateTime.now().toString());
state.put("activity", activity);