Question

This is probably pretty simple but I haven’t been able to figure out how to phrase the question for Google, so here goes:

So, I often do something like this…

class foo {
    private $bar = array();
}

… to set some class property to be an array. However, I’d like to make a private property an object instead, something like this:

class foo {
    private $bar = new stdClass();
}

I tried several variations of this and none of them worked. Can this be done? For bonus points can you assign a private property to be any other class of object?

Thanks!

Answer 1

You can’t use functions (including constructors) in class member declarations. Instead set it up in the constructor for the class.

class Foo {

  private $bar;

  private $baz;

  public function __construct() {

    $this->bar = new stdClass();
    $this->baz = new Bat();

  }

  public function __get($key) {
      if(isset($this->$key) {
        return $this->$key;
      }

      throw new Exception(sprintf('%s::%s cannot be accessed.', __CLASS__, $key));
  }

}


$foo = new Foo();

var_dump($foo->bar);
var_dump($foo->bat);

And when you extend the class and need to override the constructor but still want the stuff in the parent classes constructor:

class FooExtended
{
   protected $coolBeans;

   public function __construct() {

      parent::__construct(); // calls the parents constructor

      $this->coolBeans = new stdClass();
   }
}

$foo = new FooExtended();

var_dump($foo->bar);
var_dump($foo->bat);
var_dump($foo->coolBeans);

It should also be noted this has nothing to do with visibility of the property… it doesn’t matter if its protected, private, or public.