Prado\Web\UI\TSessionPageStatePersister::setHistorySize PHP Method

    public function setHistorySize($value)
    {
        if (($value = TPropertyValue::ensureInteger($value)) > 0) {
            $this->_historySize = $value;
        } else {
            throw new TInvalidDataValueException('sessionpagestatepersister_historysize_invalid');
        }
    }