* (thru {@link #addChartDataListener}.
*
* <p>Note: you can invoke this method only in an event listener.
*/
protected void fireEvent(int type, Comparable series, Object data) {
final ChartDataEvent evt = new ChartDataEvent(this, type, series, data);
for (Iterator it = _listeners.iterator(); it.hasNext();)
((ChartDataListener)it.next()).onChange(evt);
}