public function assignExisting ( $propName, $propValue ) {
        if (is_bool( $this->$propName )) {
            if (strtolower( $propValue ) == 'false') {
                $propValue = false;
            }
            $this->$propName = (bool) $propValue;
        } elseif (is_int( $this->$propName )) {
            $this->$propName = (int) $propValue;
        } elseif (is_bool( $this->$propName )) {
            $this->$propName = (bool) $propValue;
        } elseif ($this->$propName instanceof Timer || $this->$propName == MapConst::TIMER) {
            $this->$propName = new Timer( $propValue );
        } else {
            $this->$propName = $propValue;
        }
    }