* @param axis the axis (<code>null</code> permitted).
*/
public void setRangeAxis(int index, ValueAxis axis, boolean notify) {
ValueAxis existing = getRangeAxis(index);
if (existing != null) {
existing.removeChangeListener(this);
}
if (axis != null) {
axis.setPlot(this);
}
this.rangeAxes.set(index, axis);