Question

I need to track which instance created another instance. It’s an instancing hierarchy not a parent-child class hierarchy. Here’s an example:

class Car{

    private var $engine;
    private var $id;

    public function __construct(){
        $this->id = nextId();
        $this->engine = new Engine(500);
    }
}

class Engine{

    private var $horsepower;
    private var $id;

    public function __construct($hp){
        $this->id = nextId();
        $this->horsepower = $hp;
    }
}

if I do:

$myCar1 = new Car();
$myEngine = new Engine(200);

I currently have 1 instance of Car and 2 of Engine. I need to know which instance created which instance. something like this:

$creator = instanceCreatorOf($myCar1->engine or $myCar1->engine->id);

would return: $myCar or $myCar->id;

but if I do:

$creator = instanceCreatorOf($myEngine or $myEngine->id);

would return: root or null or 0;

I need to track this but having a lot of dynamically created objects I need dynamic tracking of this hierarchy. Any ideas?
thanks!

Answer 1

Can you have an Car create its own engine and pass in a reference to itself:

class Car {
  function __construct() {
    myEngine = new Engine(this);
...

and

class Engine {
 var $creator;
 function __construct(Car $car, $horsepower) {
  $this->creator = $car;
...