title: XYPointerAnnotation in TimeSeries JFreeChart
body: <p>I'm trying to implement <code>XYPointerAnnotation</code> to <code>TimeSeries</code> chart. However I don't know, how does chart finds my y values to plot. Code:</p>
  
  <pre><code>final TimeSeries series = new TimeSeries("asdfas");
  Hour hour = new Hour();
  series.add(2,hour), 123);
  TimeSeriesCollection collection = new TimeSeriesCollection();
  collection.addSeries(series);
  double temp = Double.parseDouble(
      series1.getTimePeriod(series1.getItemCount()-1).toString());
  XYPointerAnnotation pointer1 = new XYPointerAnnotation(
      series1.getValue(series1.getItemCount() - 1).toString(), temp, 00.0);
  JFreeChart chart = ChartFactory.createTimeSeriesChart(
      "1", "2", "3", collection, true, true, false);
  </code></pre>
  
  <p>How can I parse y values from <code>TimeSeries</code> to the <code>XYPointerAnnotation</code>?</p>