public class DNode implements Position {
	private DNode prev, next;	// References to the nodes before and after
	private Object element;		// Element stored in this position

	// Constructor
	public DNode(DNode newPrev, DNode newNext, Object elem) {
		prev = newPrev;
		next = newNext;
		element = elem;
	}

	// Method from interface Position
	public Object element() throws ExceptionInvalidPosition {
		if ((prev == null) && (next == null))
			throw new ExceptionInvalidPosition("Position is not in a list!");
		return element;
	}

	// Accessor methods
	public DNode getNext() { return next; }
	public DNode getPrev() { return prev; }

	// Update methods
	public void setNext(DNode newNext) { next = newNext; }
	public void setPrev(DNode newPrev) { prev = newPrev; }
	public void setElement(Object newElement) { element = newElement; }

}