Function that uses an exception to check if user exists

Question

I have a User class that will throw an exception if the userid provided in the parameter does not correspond with a user.

I've written a helper function that will return true or false depending on whether a userid belongs to a user or not, but was wondering if my use of a try {} catch {} to do so is correct:

    private function userExists($userid)
    {
       $user_does_not_exist = false;
       try
       {
          $user = new User($userid);
       }
       catch (Exception $e)
       {
          $user_does_not_exist = true;  
       }

       return $user_does_not_exist;
   }

Any and all critique is greatly appreciated.

Answer 1

I would suggest working the other way around. Expect that a user does not exist and only return true if a user is found.

private function UserExists($userId)
{
    $userExists = false;

    try
    {
        $user = new User($userId);
        if($user !== null)
            $userExists = true;
    }
    catch (Exception $e)
    {
        //handle exception
    }

    return $userExists;
}

You can drive this further and ease things by not using a variable to return, like this:

private function UserExists($userId)
{
    try
    {
        return new User($userId) !== null;
    }
    catch (Exception $e)
    {
        return false;  
    }
}