Looks like a stupid bug.  As a first cut, try replacing the PieChartSeriesAttributes.getElements() method with:

    Object[] getElements() 
        {
        if (elements != null) return elements;
        else if (elements2 != null) return elements2.toArray();
        else return null;
        }

Sean

On Sep 1, 2015, at 7:56 PM, Tschanen Miriam <[log in to unmask]> wrote:

> Hi all,
> 
> I'm trying to set up a custom bar chart for my model, since the level of control I have over the default inspectors isn't quite enough for my needs. I stumbled upon the sim.display.ChartUtilities class and tried to use it to attach a bar chart directly to my simulation. Unfortunately, I can't figure out how to use it correctly, or rather I am constantly getting a NullPointerException as soon as the simulation runs.
> 
> As outlined in its documentation, I call the following functions in my GUIstate class to set up the bar chart:
> 
> public void init(Controller c) {
>     ...
> 
>     BarChartGenerator bcgenerator = ChartUtilities.buildBarChartGenerator(this, "Bar Chart");
>     barchart = ChartUtilities.addSeries(bcgenerator, "Bar Chart");  <-- this is where the exception triggers
> }
> 
> public void setupPortrayals() {
>     ...
> 
>     ChartUtilities.scheduleSeries(this, barchart, sim.data);
> }
> 
> These are the top few lines of the trace:
> java.lang.NullPointerException
>     at sim.util.media.chart.PieChartSeriesAttributes.getElements(PieChartSeriesAttributes.java:40)
>     at sim.util.media.chart.PieChartGenerator.update(PieChartGenerator.java:136)
>     at sim.util.media.chart.PieChartGenerator.addSeries(PieChartGenerator.java:187)
>     at sim.display.ChartUtilities.addSeries(ChartUtilities.java:569)
> 
> Either I'm missing something important or there is a bug in the implementation of addSeries. Is there some other way I can create a bar chart with full control over the labels and categories? As I mentioned, the default inspector isn't much help, for instance it sorts numerical categories in an awful way (placing 10 before 2 etc).
> 
> Cheers,
> Miriam Tschanen