public function valid()
    {
        $bIsValid = false;
        if (null !== $this->values) {
            $sKey     = $this->key();
            $bIsValid = isset($sKey);
        }

        return $bIsValid;
    }
public function valid()
    {
        $bIsValid = false;
        if (null !== $this->values) {
            $sKey     = $this->key();
            $bIsValid = isset($sKey);
        }

        return $bIsValid;
    }
public function valid ( ) { $ bIsValid = false ; if ( null !== $ this -> values ) { $ sKey = $ this -> key ( ) ; $ bIsValid = isset ( $ sKey ) ; } return $ bIsValid ; }
check if the the current value is set

@return bool True if set, otherwise false
check if the the current value is set