Using methods to access classes and the instantiate them - php

Question

I have stored the class I want to instantiate in a variable that is accessible via get and set methods:
private $myClass;
public function setClass($myClass) {$this->myClass = $myClass;}
public function getClass() {return $this->myClass;}
Now later on I want to instantiate this class using the get method:
$instance = new $getClass()();
And also work with some of it's static attributes:
$staticAttr = $getClass()::$attr;
But both of these lines throw errors, I think I've found a solution but I'm really not certain and I feel that my problem is some fundamental lack of understand about how to do this. Or perhaps it is just awful practice and so highly discouraged? How best should I go about approaching this?

Answer 1

PHP's syntax does not allow for this. In order to get this working, you just need to store the class name to a variable first:
$class_name = $obj->getClass();
$instance = new $class_name();
The same goes for accessing the static property:
$class_name = $obj->getClass();
$staticAttr = $class_name::$attr;

Answer 2

This is wrong
$instance = new $getClass()();
Instead do this
$getClass = "classname";
$instance = new $getClass();
for static functions do this
$getClass::getMethod();
For static members
$getClass::$attr;

Answer 3

Tweaking your code to a working object:
class someObject {
private $myClass;
public function setClass($myClass) {$this->myClass = $myClass;}
public function getClass() {return $this->myClass;}
}
Sample
$a = new someObject();
$a->setClass(new stdClass());
var_dump($a->getClass());
You can access $a->getClass()->property, for static properties:
class Foo {
public static $a = 'bar';
}
$a->setClass(new Foo());
$class = $a->getClass();
var_dump($class::$a);