long upper = Math.round(range.getUpperBound());
        long lower = Math.round(range.getLowerBound());
        this.first = createInstance(this.autoRangeTimePeriodClass, 
                new Date(lower), this.timeZone);
        this.last = createInstance(this.autoRangeTimePeriodClass, 
                new Date(upper), this.timeZone);