java嵌套类的数据成员

Question

I have an AVLTREE class, and inside it an inner class which is an iterator. The iterator is instanciated by the user request only. Suppose I have this code:

tree.add(10);
tree.add(6);
tree.add(19);

Iterator<Integer> it1 = tree.iterator();
System.out.println(it1.next());
System.outrintln(it1.next());

tree.delete(10);

System.outrintln(it1.next());

the sysrem will print "null" , althogh the tree has another value: 19. How do I approach the instance of a specific Iterator and change its current node to be the successor of the deleted node in such cases?

Thanks!

Answer 1

Modifying the underlying collection while iterating through them is a problematic case, that's why the inbuilt collections of Java would be throwing ConcurrentModificationException at your face when you deleted from them while in a for loop, for example. iterator.remove() is the safer way to remove elements from the collection.

As for approaching the iterator, you can't unless you store every iterator of the collection somewhere and have the iterators allow internal "tweaking" of their status, which isn't very feasible in the long run.