public void traverseInOrder() {
ThreadedBinaryNode<T> t = firstInOrderNode();
while (t != null) {
System.out.println(t);
t = t.inOrderSuccessor();
}
}
public void traverseInOrderBackwards() {
ThreadedBinaryNode<T> t = lastInOrderNode();
while (t != null) {
System.out.println(t);
t = t.inOrderPredecessor();
}
}
void insert(T x, ThreadedBinaryNode<T> t) throws DuplicateItem {
if (x.compareTo(t.element) < 0)
if (t.isLeftThread) {
t.left = new ThreadedBinaryNode(x, t.left, t);
t.isLeftThread = false;
} else insert(x, t.left);
else if (x.compareTo(t.element) > 0)
if (t.isRightThread) {
t.right = new ThreadedBinaryNode(x, t, t.right);
t.isRightThread = false;
} else insert(x, t.right);
else throw new DuplicateItem("attempt to insert duplicateitem");
}