public function setIdentifier($identifier)
    {
        if (is_string($identifier) === false || empty($identifier) === true) {
            throw new InvalidArgumentException(
                "The 'identifier' argument must be a non-empty string."
            );
        }
        
        $this->identifier = $identifier;
    }
public function setIdentifier($identifier)
    {
        if (is_string($identifier) === false || empty($identifier) === true) {
            throw new InvalidArgumentException(
                "The 'identifier' argument must be a non-empty string."
            );
        }
        
        $this->identifier = $identifier;
    }
public function setIdentifier ( $ identifier ) { if ( is_string ( $ identifier ) === false || empty ( $ identifier ) === true ) { throw new InvalidArgumentException ( "The 'identifier' argument must be a non-empty string." ) ; } $ this -> identifier = $ identifier ; }
Set the identifier on which the validity constraint applies to.

@param integer $identifier
@throws \InvalidArgumentException If $identifier is an empty string.
Set the identifier on which the validity constraint applies to .