ValueTick tick = (ValueTick) iterator.next();
                double v = this.domainAxis.valueToJava2D(tick.getValue(), 
                        dataArea, RectangleEdge.BOTTOM);
                Line2D line = new Line2D.Double(v, dataArea.getMinY(), v, 
                        dataArea.getMaxY());
                g2.setPaint(getDomainGridlinePaint());
                g2.setStroke(getDomainGridlineStroke());
                g2.draw(line);