Question

Hi
I want to know that how can I copy my objects from an arrayList to a doubly linked list?
also my DNode constructor is :

    public DNode(Object element, DNode prev, DNode next) {
    this.element = element;
    this.next = next;
    this.prev = prev;
}

i.e. when I write such a code my program doesn’t work :

  DNode node = new DNode(pointList.get(0),null, null);

        for (int i = 1; i < pointList.size(); i++) {
        DNode dNode = new DNode(pointList.get(i), node, null);
        dList.addLast(dNode);
        }

also i have written doubly linked list which has addAfter and addBefore methods and also much more.

Answer 1

java.util.LinkedList is a doubly-linked list.

All of the operations perform as could be expected for a doubly-linked list.

You can create it by passing the array list as constructor argument:

List linkedList = new LinkedList(arrayList);

Update: The java.util.LinkedList has add(index, element) which, combined with indexOf(..) should cover the addBefore and addAfter methods. You can extend LinkedList to add these convenient methods if you like.