public void setMinimumDate(Date date) {
        if (date == null) {
            throw new IllegalArgumentException("Null 'date' argument.");
        }
        // check the new minimum date relative to the current maximum date
        Date maxDate = getMaximumDate();
        long maxMillis = maxDate.getTime();
        long newMinMillis = date.getTime();
        if (maxMillis <= newMinMillis) {
            Date oldMin = getMinimumDate();
            long length = maxMillis - oldMin.getTime();
            maxDate = new Date(newMinMillis + length);
        }
        setRange(new DateRange(date, maxDate), true, false);
        notifyListeners(new AxisChangeEvent(this));