public class LinkedListNode<E> {

 public LinkedListNode<E> previous;

 public LinkedListNode<E> next;

 public E object;

 /**
 * This class is further customized for the CoolServlets cache system. It
 * maintains a timestamp of when a Cacheable object was first added to
 * cache. Timestamps are stored as long values and represent the number of
 * milleseconds passed since January 1, 1970 00:00:00.000 GMT.
 * <p>
 * The creation timestamp is used in the case that the cache has a maximum
 * lifetime set. In that case, when [current time] - [creation time] &gt;
 * [max lifetime], the object will be deleted from cache.
 * </p>
 */
 public long timestamp;

 /**
 * Constructs an self-referencing node. This node acts as a start/end
 * sentinel when traversing nodes in a LinkedList.
 */
 public LinkedListNode() {
 previous = next = this;
 }

 /**
 * Constructs a new linked list node.
 *
 * @param object the Object that the node represents.
 * @param next a reference to the next LinkedListNode in the list.
 * @param previous a reference to the previous LinkedListNode in the list.
 */
 public LinkedListNode(E object, LinkedListNode<E> next, LinkedListNode<E> previous) {
 if (next != null && previous != null) {
 this.insert(next, previous);
 }
 this.object = object;
 }

 /**
 * Removes this node from the linked list that it was a part of.
 * 
 * @return This node; next and previous references dropped
 */
 public LinkedListNode<E> remove() {
 previous.next = next;
 next.previous = previous;
 previous = next = null;
 return this;
 }

 /**
 * Inserts this node into the linked list that it will be a part of.
 * 
 * @return This node, updated to reflect previous/next changes
 */
 public LinkedListNode<E> insert(LinkedListNode<E> next, LinkedListNode<E> previous) {
 this.next = next;
 this.previous = previous;
 this.previous.next = this.next.previous = this;
 return this;
 }

 /**
 * Returns a String representation of the linked list node by calling the
 * toString method of the node's object.
 *
 * @return a String representation of the LinkedListNode.
 */
 @Override
 public String toString() {
 return object == null ? "null" : object.toString();
 }

}