apache-poi 4.0 NullPointer for series setTitle

3
votes

Exception in thread "main" java.lang.NullPointerException at org.apache.poi.xddf.usermodel.chart.XDDFChartData$Series.setTitle(XDDFChartData.java:122)

The code follows as below:

CellReference cellref = new CellReference("A6"); 

//A6 value = "My Title"

XDDFLineChartData.Series series3 = (XDDFLineChartData.Series)data.addSeries(xs, ys3);
series3.setMarkerSize((short) 6);
series3.setMarkerStyle(MarkerStyle.DIAMOND);

series3.setTitle("My Title",cellref);

I checked the documentation, it required a string for arg0 and a CellReference for arg1.

I keep ending up with a NullPointerException. Am I missing something??

Thanks for the replies.

1
javachartsapache-poiapache-poi-4
The new XDDF stuff seems far away from being useable until now. in XDDFChartData.Series.setTitle getSeriesText() is used without null check. But XDDFLineChartData.Series.getSeriesText of course may return null since series.getTx() may return null. - Axel Richter

1 Answers

2
votes

To answer the question how to repair the bug in XDDFChartData.Series.setTitle:

In XDDFChartData.Series.setTitle getSeriesText() is used without null check. But XDDFLineChartData.Series.getSeriesText() of course may return null since series.getTx() may return null. So we need make sure, that there is a series text element already before using XDDFChartData.Series.setTitle.

...
XSSFChart chart = drawing.createChart(anchor);
...
XDDFCategoryAxis bottomAxis = chart.createCategoryAxis(AxisPosition.BOTTOM);
XDDFValueAxis leftAxis = chart.createValueAxis(AxisPosition.LEFT);
...
XDDFChartData data = chart.createData(ChartTypes.LINE, bottomAxis, leftAxis);
data.addSeries(...);
data.addSeries(...);
chart.plot(data);

if (chart.getCTChart().getPlotArea().getLineChartArray(0).getSerArray(0).getTx() == null) 
 chart.getCTChart().getPlotArea().getLineChartArray(0).getSerArray(0).addNewTx();
data.getSeries().get(0).setTitle("Series 1 Title", null);

if (chart.getCTChart().getPlotArea().getLineChartArray(0).getSerArray(1).getTx() == null)
 chart.getCTChart().getPlotArea().getLineChartArray(0).getSerArray(1).addNewTx();
data.getSeries().get(1).setTitle("Series 2 Title", null);
...
//setting the axis Ids to the LineChart
chart.getCTChart().getPlotArea().getLineChartArray(0).addNewAxId().setVal(bottomAxis.getId());
chart.getCTChart().getPlotArea().getLineChartArray(0).addNewAxId().setVal(leftAxis.getId());
...