Neos.ContentRepository/Classes/Validation/Validator/NodeIdentifierValidator.php
protected function isValid($value)
    {
        if (!is_string($value) || !preg_match(self::PATTERN_MATCH_NODE_IDENTIFIER, $value)) {
            $this->addError('The given subject was not a valid node identifier.', 1489921024);
        }
    }
protected function isValid($value)
    {
        if (!is_string($value) || !preg_match(self::PATTERN_MATCH_NODE_IDENTIFIER, $value)) {
            $this->addError('The given subject was not a valid node identifier.', 1489921024);
        }
    }
protected function isValid ( $ value ) { if ( ! is_string ( $ value ) || ! preg_match ( self :: PATTERN_MATCH_NODE_IDENTIFIER , $ value ) ) { $ this -> addError ( 'The given subject was not a valid node identifier.' , 1489921024 ) ; } }
Checks if the given value is a syntactically valid node identifier.

@param mixed $value The value that should be validated
@return void
@api
Checks if the given value is a syntactically valid node identifier .