public void removeDataPointListener(int dataPointId, DataPointListener l) {
DataPointListener listeners =
DataPointEventMulticaster.remove(dataPointListeners.get(dataPointId), l);
if (listeners == null) dataPointListeners.remove(dataPointId);
else dataPointListeners.put(dataPointId, listeners);
}
public void addDataPointListener(int dataPointId, DataPointListener l) {
DataPointListener listeners = dataPointListeners.get(dataPointId);
dataPointListeners.put(dataPointId, DataPointEventMulticaster.add(listeners, l));
}