/** {@inheritDoc} */
 @Override
 public boolean isSelected(final Date date) {
   Contract.asNotNull(date, "date must not be null");
   return selectedDates.contains(date);
 }
 /**
  * {@inheritDoc}
  *
  * <p>
  */
 @Override
 public void setSortOrderCycle(SortOrder... cycle) {
   Contract.asNotNull(cycle, "Elements of SortOrderCycle must not be null");
   // JW: not safe enough?
   sortCycle = Arrays.asList(cycle);
 }