public Datapoint getVisibleLastDatapointLocking() {
Datapoint last = null;
waitForLock();
for (int i = 0; i < mSeries.size(); i++) {
TimeSeries ts = mSeries.get(i);
if (ts != null && ts.isEnabled() == true) {
Datapoint d = ts.getLastVisible();
if (last == null) last = d;
else if (d.mMillis > last.mMillis) last = d;
}
}
unlock();
return last;
}
