protected void drawDomainGridlines(Graphics2D g2, Rectangle2D dataArea,
                                       List ticks) {

        // no renderer, no gridlines...
        if (getRenderer() == null) {
            return;
        }

        // draw the domain grid lines, if any...
        if (isDomainGridlinesVisible()) {
            Stroke gridStroke = getDomainGridlineStroke();
            Paint gridPaint = getDomainGridlinePaint();
            if ((gridStroke != null) && (gridPaint != null)) {
                Iterator iterator = ticks.iterator();
                while (iterator.hasNext()) {
                    ValueTick tick = (ValueTick) iterator.next();
                    getRenderer().drawDomainGridLine(g2, this, getDomainAxis(),
                            dataArea, tick.getValue());