Give a linechart XAxis academic month order

Question

I have created a simple line chart where I compare the current years values to past years (could be an average or not).

The issue is that as this is for UK Academic purposes I want the months to run from June through to June the following year.

Currently my code looks like:

xAxis.setLabel("Date/Month");
    xAxis.setTickLabelRotation(90);

    xAxis.setAutoRanging(false);
    xAxis.setLowerBound(1);
    xAxis.setUpperBound(12);
    xAxis.setTickUnit(1.0);

    xAxis.setTickLabelFormatter(new StringConverter<Number>() {

        @Override
        public String toString(Number month) {
            logger.debug("Converting " + month);
            return new DateFormatSymbols().getMonths()[month.intValue()-1];
        }

        @Override
        public Number fromString(String string) {
            try {
                Date date = new SimpleDateFormat("MMMM").parse(string);
                Calendar cal = Calendar.getInstance();
                cal.setTime(date);
                return cal.get(Calendar.MONTH);
            } catch (ParseException ex) {
                logger.error("Parse Exception");
            }
            return  0;
        }

    });


    yAxis.setLabel("Units");

where the series are created using a simple function:

    private XYChart.Series createSeries(String name, List<AccountUtilities> data) {
    XYChart.Series series = new XYChart.Series();
    series.setName(name);
    for (AccountUtilities utility : data) {
        String[] dateParts = utility.getStartdate().split("-");
        Double dateCode = Double.valueOf(dateParts[1]);
        series.getData().add(new XYChart.Data( dateCode , utility.getGasunits()));
    }
    return series;
}

My current thought is that I can reindex the months as June = 1, July = 2 etc. to get the values into the chart in the correct order and then decode them into their 'correct' values June = 6 when I get setTickLabelFormatter to do its thing but this seems a long way around.

Is there a nifty feature of javafx charting that I'm missing?

Current resources used:

• javafx line chart with date axis
• How to perform big numbers on axis (for example, 10^3 format) in chart?

Answer 1

So I followed my initial thought process and although it was more complicated than I initially thought with any offset that wasn't 6 months the following works for both 6 and 8. The following method reorders Jan(1) to Dec(12) to the offsetted order e.g. Jun(1) to May(12) so the data appears in the desired order in the chart.

private Double getAcademicMonth(String baseDate) {
    Integer dateCode = Integer.valueOf(baseDate);

    //Any month greater than the accounting start month gets shifted by six.
    if (dateCode > offset) { dateCode = dateCode - offset; }
    else { dateCode = dateCode + (12-offset); }

    return dateCode;
}

I then required a means of converting the months back on the fly when the chart was drawn so I got the correct month labels, which was achieved with setTickLabelFormatter

    //We have to set tick label formatter now once the offset has been retrieved.
    xAxis.setTickLabelFormatter(new StringConverter<Number>() {

        @Override
        public String toString(Number month) {

            //Shift our months to account for the accounting start month
            int dateCode = month.intValue();
            if (dateCode <= (12 - offset) ) { dateCode = dateCode + offset; }
            else { dateCode = dateCode - (12-offset); }

            Month day = Month.of(dateCode);
            return day.getDisplayName(TextStyle.SHORT, Locale.ENGLISH);

        }

        @Override
        public Number fromString(String string) {
          DateTimeFormatter parser = DateTimeFormatter.ofPattern("MMMM").withLocale(Locale.ENGLISH);
          TemporalAccessor accessor = parser.parse(string);
          return accessor.get(ChronoField.MONTH_OF_YEAR);
        }

    });