yii\validators\DateValidator::init PHP Method

    public function init()
    {
        parent::init();
        if ($this->message === null) {
            $this->message = Yii::t('yii', 'The format of {attribute} is invalid.');
        }
        if ($this->format === null) {
            if ($this->type === self::TYPE_DATE) {
                $this->format = Yii::$app->formatter->dateFormat;
            } elseif ($this->type === self::TYPE_DATETIME) {
                $this->format = Yii::$app->formatter->datetimeFormat;
            } elseif ($this->type === self::TYPE_TIME) {
                $this->format = Yii::$app->formatter->timeFormat;
            } else {
                throw new InvalidConfigException('Unknown validation type set for DateValidator::$type: ' . $this->type);
            }
        }
        if ($this->locale === null) {
            $this->locale = Yii::$app->language;
        }
        if ($this->timeZone === null) {
            $this->timeZone = Yii::$app->timeZone;
        }
        if ($this->min !== null && $this->tooSmall === null) {
            $this->tooSmall = Yii::t('yii', '{attribute} must be no less than {min}.');
        }
        if ($this->max !== null && $this->tooBig === null) {
            $this->tooBig = Yii::t('yii', '{attribute} must be no greater than {max}.');
        }
        if ($this->maxString === null) {
            $this->maxString = (string) $this->max;
        }
        if ($this->minString === null) {
            $this->minString = (string) $this->min;
        }
        if ($this->max !== null && is_string($this->max)) {
            $timestamp = $this->parseDateValue($this->max);
            if ($timestamp === false) {
                throw new InvalidConfigException("Invalid max date value: {$this->max}");
            }
            $this->max = $timestamp;
        }
        if ($this->min !== null && is_string($this->min)) {
            $timestamp = $this->parseDateValue($this->min);
            if ($timestamp === false) {
                throw new InvalidConfigException("Invalid min date value: {$this->min}");
            }
            $this->min = $timestamp;
        }
    }

 public function init()
 {
     if ($this->timestampAttributeFormat === null) {
         $this->timestampAttributeFormat = 'yyyy-MM-dd';
     }
     if ($this->timestampAttribute === null) {
         $this->timestampAttribute = $this->sqlAttribute;
     }
     parent::init();
 }