Vaadin chart not showing

Hi. 

I'm trying to visualize a lot of data using Vaadin Charts. 
The problem is that some specific charts started to disapeer. The area for the chart is showing a loading symbol for 10ms or something, and then goes to white, though the component is added. 

When I try to add the chart, i tried to sysout the Caption, and as expected the chart was created, and all the data seems legit.
Sometimes all the charts are showing, other times not - but the first two charts are showing alle the time. 

I first thought it was threading-issue, so I removed ALL threading, and tried again. No dice. Then I though maybe I had too many charts in one vertical layout, so I added two charts per tabsheet, though it still failed 95% of the time. The I tried setting a delay on 1 sec between the creations - still no luck. 

What is happening? It's the same data all the time, but sometimes the charts (only theese specific ones), wont be shown for the user. 

First itteration gives a working sheet with charts:

All other tabs (itterations)

The code generating the tabsheet with the charts. Beware that the error existed before the tab-sheets were introduced, so that is not the problem.

private void initTabsheet() {
Date from = fromDate.getValue();
Date to = toDate.getValue();
ChartMaker chartMaker = new ChartMaker(from, to, new ArrayList<String>(hardwares));
TabSheet hwSheet = new TabSheet();
VerticalLayout sumTab = new VerticalLayout();
VerticalLayout statisticsTab = new VerticalLayout();
VerticalLayout firmwareTab = new VerticalLayout();

// These works just fine
sumTab.addComponent(chartMaker.getBarAccumulationHardwareDeviceTime(from, to, new ArrayList<String>(hardwares)));
sumTab.addComponent(chartMaker.getBarAccumulationHardwareBoots(from, to, new ArrayList<String>(hardwares)));
sumTab.addComponent(chartMaker.getBarAccumulationHardwareTickets(from, to, new ArrayList<String>(hardwares)));

sumTab.addComponent(chartMaker.getHistoricAccumulationHardwareDevicetime(from, to, new ArrayList<String>(hardwares)));
sumTab.addComponent(chartMaker.getHistoricAccumulationHardwareBoots(from, to, new ArrayList<String>(hardwares)));
sumTab.addComponent(chartMaker.getHistoricAccumulationHardwareTickets(from, to, new ArrayList<String>(hardwares)));


statisticsTab.addComponent(chartMaker.getHistoricStatisticsHardwareBootrate(from, to, new ArrayList<String>(hardwares)));
statisticsTab.addComponent(chartMaker.getHistoricStatisticsHardwareErrorrate(from, to, new ArrayList<String>(hardwares)));

// It is this loop that generates the charts, where only the first itteration actually 
// works (Or they do work, the charts are created, but no
for (String hw : hardwares) {
    VerticalLayout tab = new VerticalLayout();
    tab.addComponent(chartMaker.getHistoricStatisticsFirmwareBootrate(from, to, hw));
    tab.addComponent(chartMaker.getHistoricStatisticsFirmwareErrorrate(from, to, hw));
    hwSheet.addTab(tab).setCaption(hw);
}
firmwareTab.addComponent(hwSheet);

subdata.addTab(sumTab).setCaption("Accumulations | Hardware");
subdata.addTab(statisticsTab).setCaption("Statistics | Hardware");
subdata.addTab(firmwareTab).setCaption("Staticstics | Firmware");
this.subdata.setVisible(true);

}

The code that generates the charts:

private Chart makeInitialChart(String title, String subtitle, String yt) {
    // Create chart
    Chart chart = new Chart(ChartType.LINE);
    Configuration conf = chart.getConfiguration();
    conf.setTitle(title);
    conf.setSubTitle(subtitle);

    // Add the dates to the x-axis
    conf.getxAxis().setType(AxisType.DATETIME);

    // Set y-axis
    YAxis y = new YAxis();
    y.setMin(0);
    y.setTitle(yt);
    conf.addyAxis(y);

    Tooltip tooltip = new Tooltip();
    tooltip.setFormatter("this.y");
    conf.setTooltip(tooltip);

    return chart;
}

public Chart getHistoricStatisticsFirmwareBootrate(Date from, Date to, String hardware) {
    Chart chart = makeInitialChart("Bootrate by " + hardware + "'s firmware", "Between " + from + " and " + to, "Bootrate");
    Configuration conf = chart.getConfiguration();

    for (String fw : dao.getDistinctFirmwareBasedOnHardware(hardware)) {
        DataSeries ls = new DataSeries();
        ls.setPlotOptions(new PlotOptionsLine());
        ls.setName(fw);

        Calendar calend = Calendar.getInstance();
        calend.setTime(from);
        Calendar beginCalendar = new GregorianCalendar(calend.get(Calendar.YEAR), calend.get(Calendar.MONTH), calend.get(Calendar.DATE));
        calend.setTime(to);
        Calendar endCalendar = new GregorianCalendar(calend.get(Calendar.YEAR), calend.get(Calendar.MONTH), calend.get(Calendar.DATE));
        while (beginCalendar.compareTo(endCalendar) <= 0) {
            DataSeriesItem item = new DataSeriesItem(beginCalendar.getTime(), getBootRateFirm(hardware, fw, beginCalendar.getTime()));
            ls.add(item);
            beginCalendar.add(Calendar.DATE, 1);
        }

        conf.addSeries(ls);
    }

    chart.drawChart(conf);

    return chart;
}

I didn't see any problem in your chart code. Did you manage to get this working already? I would need a smaller self-contained project to try to debug the issue. Can you provide such?

Hi Johannes. 

Thank you! I couldn't find the problem at first either. 
The problem was divison by zero, wich is apparently not thrown, when using doubles - http://grouper.ieee.org/groups/754/ 

I had a method deeper down looking like: 

public Double getErrorRateByFWAndDate(String fw, String hw, Date date) {
    if (!knownDates.contains(date)) return 0.0;

    double tt = 0.0;
    double dt = 0.0;
    for (Errorstatistic errorstatistic : esMap.get(date)) {
        if (errorstatistic.getFirmware().equals(fw) && errorstatistic.getHardware().equals(hw)) {
            tt += errorstatistic.getTicketstotal() == null ? 0.0 : errorstatistic.getTicketstotal();
            dt += errorstatistic.getDevicetime() == null ? 0.0 : errorstatistic.getDevicetime();
        }
    }
    return tt / dt;
}

So there was a chance the database would return zero, hence giving a division-by-zero error. 

Simply fixed it with:

if(dt == 0.0) return 0.0;

It sure does suck not seing that!

Anyway - you're help a second set of eyes are much appreciated.

Best regards,
Ben

Wow what an annoying bug. Well, I'm glad you found the reason.