@Override
 public Object Next() {
   Object rect = null;
   current++;
   if (current < aggregate.count()) {
     rect = aggregate.get(current);
   }
   return rect;
 }
 @Override
 public Object CurrentItem() {
   return aggregate.get(current);
 }
 @Override
 public Object First() {
   return aggregate.get(0);
 }