Use more than one -> in the same PHP code line

Question

I made my transition from Java to PHP and recently bumped into something I used to do in Java but am not able to do in php.

The following code creates an object of type "User"

public function validateUser() {
    //Check if information entered by user is valid
    $user = new User($_POST);
    new UserControl($user);
}

I need to do a validation if Cpf is numeric before proceeding with the validation with the formula. In Java I would use something like:

int cpf = this.getUser().getUserCpf();

The php code looks like this:

class UserControl {
private $user;

public function __construct($user) {
   $this->setUser($user);
}


public function validateIntegers() {
  $cpf = $this->getUser()->getUserCpf();
  is_numeric($cpf);
}

But the same logic does not apply. Is there any other way to use this object orientation in PHP? Or is it not possible to do something like this?