public function setResponseIdentifier($responseIdentifier)
    {
        if (Format::isIdentifier($responseIdentifier, false) === true) {
            $this->responseIdentifier = $responseIdentifier;
        } else {
            $msg = "The 'responseIdentifier' argument must be a valid QTI identifier.";
            throw new InvalidArgumentException($msg);
        }
    }
public function setResponseIdentifier($responseIdentifier)
    {
        if (Format::isIdentifier($responseIdentifier, false) === true) {
            $this->responseIdentifier = $responseIdentifier;
        } else {
            $msg = "The 'responseIdentifier' argument must be a valid QTI identifier.";
            throw new InvalidArgumentException($msg);
        }
    }
public function setResponseIdentifier ( $ responseIdentifier ) { if ( Format :: isIdentifier ( $ responseIdentifier , false ) === true ) { $ this -> responseIdentifier = $ responseIdentifier ; } else { $ msg = "The 'responseIdentifier' argument must be a valid QTI identifier." ; throw new InvalidArgumentException ( $ msg ) ; } }
Set the response variable associated with the interaction.

@param string $responseIdentifier A QTI identifier.
@throws \InvalidArgumentException If $responseIdentifier is not a valid QTI identifier.
Set the response variable associated with the interaction .