Linked Lists - Building Java Programs: A Back to Basics Approach - page 967

E result = current.data;
current = current.next;
removeOK = true;
return result;
}
For the remove method, your code will look like this:
public void remove() {
if (!removeOK) {
throw new IllegalStateException();
}
ListNode<E> prev2 = current.prev.prev;
prev2.next = current;
current.prev = prev2;
size--;
removeOK = false;
}
Notice that, to remove a node, you have to reset both a next and a prev pointer in
the list because now you are working with a doubly linked list.
Before we leave the subject of iterators, you should consider briefly how to imple-
ment the addAll method for your LinkedList class. Keep in mind that its header
will refer to your List interface:
public void addAll(List<E> other) {
...
}
You have to write this code in such a way that it can take either a LinkedList or
an ArrayList as a parameter. That means that you have to use methods mentioned in
the interface. One misguided approach would be to use a for loop and repeatedly
call get to retrieve each element:
// inefficient implementation of addAll method
public void addAll(List<E> other) {
for (int i = 0; i < other.size(); i++) {
add(other.get(i));
}
}
This code will work, but it will be extremely inefficient when other is a
LinkedList . Each time you call the get method, you have to start at the front of
the list and skip nodes until you get to the right spot. It is much better to use an iter-
ator to solve this problem. You can make it particularly simple by using a for-each