Sorted Doubly linked List

[student2889]

I required to create a sorted doubly linked list for my homework. Inside the SortedStringList, I need to implement a method called insert(). I have some problem in doing so. I don't what is going wrong to my code below:

public class SortedStringList {

   private static class Node {
    public String value;
    public Node previous, next;

    public Node(String v, Node p, Node n) {
        value = v;
        previous = p;
        next = n;
    }
}

private Node first;
private Node last;

public SortedStringList(){
    this.first = null;
    this.last = null;
}

public void insert(String s){
    Node newnode = new Node(s,this.first,this.last);
    if(first == null){
        first = newnode;
    }
 else
     if(first.value.compareTo(s) >= 0){
         newnode.next = first;
         newnode.previous = null;
         first = newnode;
         last = first;
     }
 else
     {
        Node current = first;
        newnode.previous = first;

        while(current.value.compareTo(s)<=0 ){
            if(current.next == null){
                current.next = newnode;
                first = current;
                last = newnode.next;

            }
            first.previous = current;
            current = current.next;
        }
            first.previous.next = newnode;
            newnode.next = current;
            current = first;
 }



}
}

Can somebody please give me some idea?

[DarrylBurke]

Cross posted
Sorted Doubly linked List - Java Programming Forums

Any more?

db