Is the page valid?

@param string $value Page to validate

@return bool
969813
public function isValid($value)
    {
        $nameOk = parent::isValid($value);

        if (!$nameOk) {
            return false;
        }

        $check = $this->pageRepo->findOneBy(
            [
                'name' => $value,
                'pageType' => $this->pageType,
                'site' => $this->siteId
            ]
        );

        if (!empty($check)) {
            $this->error(self::PAGE_EXISTS);

            return false;
        }

        return true;
    }
604478
public function isValueValid($value) {
		return $value instanceof DataType\NumberType || $value instanceof Type\PriceSpecificationType || $value instanceof DataType\TextType;
	}
770299
public function isValueValid($value) {
		return $value instanceof Type\CreativeWorkType || $value instanceof Type\ProductType || $value instanceof DataType\URLType;
	}
153355
public function isValid($value)
    {
        $result = (boolean) filter_var($value, FILTER_VALIDATE_URL);
        if (!$result) {
            $this->addMessage('url');
        }
        return $result;
    }
620762
public function isValueValid($value) {
		return $value instanceof Type\Product || $value instanceof DataType\TextType || $value instanceof DataType\URLType;
	}
904919
public static function validateUrl($value)
    {
        if (($url = parse_url($value)) && ! empty($url['scheme']) && ! empty($url['host'])) {
            return true;
        }
        return false;
    }
1060467
public function isValueValid($value) {
		return $value instanceof Type\ListItemType || $value instanceof DataType\TextType || $value instanceof Type\ThingType;
	}
570722
public function isValid($value)
    {
        foreach ((array) $value as $val) {
            if (\MUtil_String::contains($val, $this->_options[0])) {
                return true;
            }
        }
        return false;
    }
1259765
public function isValueValid($value) {
		return $value instanceof Type\CreativeWorkType || $value instanceof Type\HowToSectionType || $value instanceof Type\HowToStepType || $value instanceof DataType\TextType;
	}
1347137
public function isValid($value)
    {
        $lines = explode("\n", $value);
        if (count($lines) > $this->lines) {
            $this->error(self::TOO_LINES);
        }
        foreach ($lines as $line) {
            if (strlen($line) > $this->lineLen) {
                $this->error(self::LINE_LONG);
                break;
            }
        }
        
        if ($this->getMessages()) {
            return false;
        }

        return true;
    }
507361
protected function _validate($value)
    {
        $value = trim($value);
        $pattern = ComHashtagsDomainEntityHashtag::PATTERN_HASHTAG;

        return (is_string($value) && (preg_match($pattern, $value)) == 1);
    }
1057270
public function isValid($value = null)
    {
        //jeśli niezaznaczony
        if ($this->getElement() && !$this->getElement()->isChecked()) {
            return $this->_error(self::INVALID);
        }
        return true;
    }
132530
public function isValid($value)
    {
        if (!is_null($value) && !is_string($value) && !is_int($value) && !is_float($value) &&
            !is_bool($value) && !is_array($value)) {
            $this->_error(self::INVALID);
            return false;
        }
        if (is_string($value) && (('' === $value) || preg_match('/^\s+$/s', $value))) {
            $this->_error(self::INVALID);
            return false;
        } elseif (is_int($value) && (0 === $value)) {
            return true;
        } elseif (!is_string($value) && empty($value)) {
            $this->_error(self::INVALID);
            return false;
        }
        return true;
    }
1335174
public function isValid($value)
    {
        $valueString = (string) $value;

        $this->_setValue($valueString);

        if ((ip2long($valueString) === false) || (long2ip(ip2long($valueString)) !== $valueString)) {
            if (!function_exists('inet_pton')) {
                $this->_error();
                return false;
            } else if ((@inet_pton($value) === false) ||(inet_ntop(@inet_pton($value)) !== $valueString)) {
                $this->_error();
                return false;
            }
        }

        return true;
    }
376040
public function isValueValid($value) {
		return $value instanceof DataType\NumberType || $value instanceof Type\PriceSpecification || $value instanceof DataType\TextType;
	}
593835
public function isValueValid($value) {
		return $value instanceof DataType\TextType || $value instanceof Type\ThingType || $value instanceof DataType\URLType;
	}
1193963
public function isValid($value)
    {
        $valueString = (string) $value;

        $this->_setValue($valueString);

        if ('' === $valueString) {
            $this->_error(self::STRING_EMPTY);
            return false;
        }

        if (null === self::$_filter) {
            /**
             * @see Zend_Filter_Digits
             */
            require_once 'Zend/Filter/Digits.php';
            self::$_filter = new Zend_Filter_Digits();
        }

        if ($valueString !== self::$_filter->filter($valueString)) {
            $this->_error(self::NOT_DIGITS);
            return false;
        }

        return true;
    }