Linked List Iteration

Assume we pass the head reference variable, which points to the front of a linked list to the following Iterator class.

Exercise Complete the implementation of hasNext and next methods.

public class LinkedList<T> implements Iterable<T> {

  private Node<T> head;

  // other fields/methods are not shown here!

  @Override
  public Iterator<T> iterator() {
    return new LinkedListIterator();
  }

  private class LinkedListIterator implements Iterator<T> {

    @Override
    public T next() {
      return null; // TODO Implement me!
    }

    @Override
    public boolean hasNext() {
      return false; // TODO Implement me!
    }
  }
}

Hint: describe the responsibilities of hasNext and next before implementing them.

private class LinkedListIterator implements Iterator<T> {
  private Node<T> current;

  public LinkedListIterator(Node<T> head) {
    current = head;
  }

  @Override
  public T next() {
    if (!hasNext()) {
      throw new NoSuchElementException();
    }

    T t = current.data;
    current = current.next;
    return t;
  }

  @Override
  public boolean hasNext() {
    return current != null;
  }
}