OOP - po změně proměnné nefunguje výpis

class Log{

    public $logs;
    public $defaultStorage = "file";
    public $id = array( "db" => 0, "file" => 0);

    public function changeStorage($type){
        switch(strtolower($type)){
            case 'db':
                $this -> defaultStorage = "db";
                exit();
            case 'file':
                $this -> defaultStorage = "file";
                exit();
            default:
                exit();
        }
    }

    public function newLog( $filename, $errorline, $description = false){
        $id = $this -> id[$this -> defaultStorage];
        $this -> logs[$this -> defaultStorage][] = array(
            "id" => $id,
            "file" => $filename,
            "line" => $errorline,
            "description" => ($description) ? $description : ""
        );
    }
    public function getLog(){
        var_dump($this -> logs);
    }
}

$log = new Log();
$log -> newLog(__FILE__, __LINE__, "Popis_file");
$log -> changeStorage("db");
$log -> newLog(__FILE__,__LINE__, "Popis_db");
$log -> getLog();