public Item[] getAllConclusionItems() {
   SortedSet<Item> conclusions = new TreeSet<Item>();
   for (AssociationRule rule : this) {
     Iterator<Item> i = rule.getConclusionItems();
     while (i.hasNext()) {
       conclusions.add(i.next());
     }
   }
   Item[] itemArray = new Item[conclusions.size()];
   conclusions.toArray(itemArray);
   return itemArray;
 }