set plot -> DatasetCount() to 0

[PollerJava]

Hi,

is it possible to set the plot- DatasetCount() to 0, because I remove all lines from the chart with the methode at the bottom but the plot.getDatasetCount()- amount remains at the amount before,
Is there any possibility to do this?

Thanks a lot,
All the best,

Code: Select all

public void removeAllLines() {
        Iterator<MyTimeSeries> it = seriesList.iterator();
        int x = 0;
        while(it.hasNext()) {                                                   // remove Dataset from the trace and the List
            MyTimeSeries ts = it.next();
            plot.setDataset(ts.getLineIndex(), null);
            plot.setRenderer(ts.getLineIndex(), null);            
            }
        seriesList.removeAll(seriesList);              
        }

[david.gilbert]

For reasons that I can't really remember, the getDatasetCount() method returns the number of slots that have been assigned for datasets, even if you reset some of them to null. I've looked at fixing this problem before - I don't remember why, but I ran into some problems so I left it as is. Maybe the quick-and-dirty solution is to add a getNonNullDatasetCount() method.

[paradoxoff]

Hi,

is it possible to set the plot- DatasetCount() to 0, because I remove all lines from the chart with the methode at the bottom but the plot.getDatasetCount()- amount remains at the amount before,
Is there any possibility to do this?

Thanks a lot,
All the best,

Code: Select all

public void removeAllLines() {
        Iterator<MyTimeSeries> it = seriesList.iterator();
        int x = 0;
        while(it.hasNext()) {                                                   // remove Dataset from the trace and the List
            MyTimeSeries ts = it.next();
            plot.setDataset(ts.getLineIndex(), null);
            plot.setRenderer(ts.getLineIndex(), null);            
            }
        seriesList.removeAll(seriesList);              
        }

The return value of plot.getDatasetCount() will never be zero. The datasets are managed in an ObjectList, and that will contain at least one entry (though the entry may be null). The same is true for the axes and renderers.
If you want to check whether the plot is "empty" (i.e. doesn´t contain any real dataset and thus couldn´t be drawn), just check for

Code: Select all

plot.getDataset() == null

[david.gilbert]

The return value of plot.getDatasetCount() will never be zero. The datasets are managed in an ObjectList, and that will contain at least one entry (though the entry may be null). The same is true for the axes and renderers.[/code]

That is exactly right...and I think the problem with fixing the non-intuitive result returned by getDatasetCount() is that JFreeChart generally expects a 1 to 1 correspondence between datasets and renderers and so there are places in the code where getDatasetCount() is used as a proxy for getRendererCount(), and straightening out that mess is something that (a) should be done but (b) will have to wait for another day.