public class PriorityQueue implements Worklist {
    private Node first = null; // first element of the Queue
    private Node last = null; // last element of the Queue
    private int size = 0;

    @Override
    public void add(String data) {
        Node tempNode = new Node(data, first);

        if (last == null) {
            first = tempNode;
            last = tempNode;
        } else if (data.compareTo(last.getData()) <= 0){
            last = tempNode;
            last.link = tempNode;

        } else {
            Node swap = last;
            remove();
            last = tempNode;
            last.link = swap;

            /*Node swap = new Node(last.getData(), last);
            remove();
            last = tempNode;
            last.link = swap;*/
        }
        size++;
    }

    @Override
    public boolean hasMore() {
        return (first != null);
    }

    @Override
    public String remove() {
        if (size == 0) {
            first = null;
            last = null;
        } else if (hasMore()){
            Node temp = first;
            first = first.getLink();
            size--;
            return temp.getData();
        }
        return null;

    }

}