Is it possible to create objects of class type within the class in php

Question

I need something like this for my school project.

class Node {
  Node $obj;   
}

How do I do this in PHP?

Answer 1

No, it's not possible. But you can type the parameters of a method and the return type :

class Node {
    private $obj = null;
    public function setNode(Node $obj) {
        $this->obj = $obj;
    }
    public function getNode():Node {
        return $this->obj;
    }
}

Note that if $obj is null you will have an error if you use getNode() . So you could use :?Node to allow null return.

    public function getNode():?Node { // OK if $this->obj is NULL
        return $this->obj;
    }

---

EDIT

To use an instance of the current object, you could use $this :

class Node {
    public $obj = null;
    public function createInstance() {
        $this->obj = $this;
    }
}

$node = new Node();
$node->createInstance();

var_dump($node);
var_dump($node->obj);

Will outputs :

object(Node)#1 (1) {
  ["obj"]=>
  *RECURSION*
}
object(Node)#1 (1) {
  ["obj"]=>
  *RECURSION*
}

As you can see $node and $node->obj are the same object ( object(Node)#1 ).