RE: [jCharts-users] Problems (NullPointer or ArrayIndex) if no d ata available for barchart

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ok. I see your point.  I will add a todo...

--- Fredrik Bertilsson <Fre...@po...> wrote:
> 
> I agree with Tamer that a validation would be a very nice thing indeed to
> have. When systems get connected together, the presentation system is not in
> control of the data. Introducing a check would imho have a minimal
> performance overhead.
> 
> Best regards,
> Fredrik
> 
> -----Original Message-----
> From: Nathaniel G. Auvil [mailto:nat...@ya...] 
> Sent: 27. februar 2004 15:02
> To: jch...@li...
> Subject: RE: [jCharts-users] Problems (NullPointer or ArrayIndex) if no data
> available for barchart
> 
> 
> 
> Well, i guess the decision was why would someone try to plot a null dataset?
> I am not sure this is something that happens very often so I would like to
> avoid the overhead and code of a validation.
> 
> 
> --- tam...@ub... wrote:
> > providing a placeholder image is exactly how we solved this issue.
> > 
> > still I was wondering, whether the cart implementation couldn't handle 
> > that. or let's say I was surprised it didn't catch that scenario and 
> > throw at least some validation exception instead of running into 
> > nullpointer.
> > 
> > 
> > -----Original Message-----
> > From: jch...@li...
> > [mailto:jch...@li...]On Behalf Of 
> > Nathaniel G. Auvil
> > Sent: Freitag, 27. Februar 2004 01:29
> > To: jch...@li...
> > Subject: Re: [jCharts-users] Problems (NullPointer or ArrayIndex) if 
> > no data available for barchart
> > 
> > 
> > 
> > If there is no data what do you expect to see in a chart?  What would 
> > be on the y-axis if there are no data elements?
> > 
> > I would think your logic, would see there was no data, and stream a 
> > placeholder image instead of the chart or a chart with a few zero 
> > values and labels of empty Strings.
> > 
> > 
> > 
> > 
> > --- tam...@ub... wrote:
> > > hi all
> > > 
> > > we are generating clusteredbarcharts based on the result of some 
> > > database selects, so the data to display is not static. we have a 
> > > problem if there is no data. I have tried different ways to tweak 
> > > this issue, but always ran into troubles:
> > > 
> > > I'm using jcharts 0.7.4 (the posted methods are the same in 0.7.5)
> > > 
> > > - legendlabels and data array (double[][]) are null
> > > 
> > > java.lang.NullPointerException
> > > 	at
> org.jCharts.chartData.AxisChartDataSet.getNumberOfDataSets(AxisChartDataSet.
> java:136)
> > > 	at 
> > > org.jCharts.chartData.AxisDataSeries.addIAxisPlotDataSet(AxisDataSer
> > > ies.java:166)
> > > 
> > > code which throws exception [AxisChartDataSet.getNumberOfDataSets]:
> > > 	public final int getNumberOfDataSets()
> > > 	{
> > > 		return this.data.length;
> > > 	}
> > > 
> > > - legenlabels is null, data array is new double[0][0];
> > > 
> > > java.lang.ArrayIndexOutOfBoundsException: 0
> > > 	at
> org.jCharts.chartData.DataSet.getNumberOfDataItems(DataSet.java:148)
> > > 	at 
> > > org.jCharts.chartData.AxisDataSeries.addIAxisPlotDataSet(AxisDataSer
> > > ies.java:168)
> > > 
> > > code which throws exception [DataSet.getNumberOfDataItems]:
> > > 	public int getNumberOfDataItems()
> > > 	{
> > > 		return this.data[ 0 ].length;
> > > 	}
> > > 
> > > is there any reason, why null and/or length is not checked in those 
> > > methods ??
> > > 
> > > is there any other way to get a empty chart, I do set
> > > setUserDefinedScale(0, 2)
> > > setNumItems(5)
> > > 
> > > 
> > > regards
> > > 
> > > tamer
> > > 
> > > 
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