如何在PHP CodeIgniter中设计拦截器，就像在Java结构中一样？

When I am using CodeIgniter to implement a small application, I want all business checking functions in controllers could be defined outside the controller for more flexible.

The checking functions just like session checking, user information completion checking, or has user post an article, and so on.

Firstly, I tried to use helper to implement. In my core controller which extended from CI_Controller I wrote a check function:

protected function check () {
    $this->checked = TRUE;
    $methods = func_get_args();
    foreach ($methods as $method) {
        $m = 'check_' . $method;
        if (!function_exists($m)) {
            $this->load->helper("filters/$m");
        }

        if ($m() === FALSE) {
            return FALSE;
        }
    }
    return TRUE;
}

Then in any controller I can use this method to check my business logic like this:

public function something ()
    if (!$this->check('session')) {
        return $this->relogin();
    }
    // ...
    if (!$this->check('userinfo')) {
        return $this->redirect('settings');
    }
    // ...
    if (!this->check('has_post')) {
        // ...  
    }
    // ...
}

But it has a problem that all helper function are global, and can't invoke protected functions in $CI instance. I didn't find a way how to invoke a instance function outside like JavaScript's call/apply.

So I turned to check the hook document of CI. But I don't think it helps, because the hook point can't be inside of any controller functions. It must be outside.

At last, I can just fallback to put all checking functions into core controller class. So I wonder is there any way to use interceptor as in Java structs?