private GraphPoint[] getSelectedPointInOrder() {
        if (this.selectlist.size() != 2) {
            return null;
        }
        Iterator<Map.Entry<Integer, GraphElement>> it = this.selectlist.entrySet().iterator();
        GraphElement gp1 = it.next().getValue();
        GraphElement gp2 = it.next().getValue();
        if (!(GraphPoint.class.isInstance(gp1) && GraphPoint.class.isInstance(gp2))) {
            return null;
        }
        GraphPoint[] gpm = {(GraphPoint)gp1, (GraphPoint)gp2};
        return gpm;
    }