Weblabor

class Identity
{
	static protected $instance;
	static public function Instance()
	{
		if (!isset(self::$instance))
			self::$instance=new self();
		return self::$instance;
	}
	
	protected $map=array();
	
	public function hashCode($object)
	{
		$hashCode=spl_object_hash($object);
		$this->map[$hashCode]=$object;
		return $hashCode;
	}
	
	public function objectFromHashCode($hashCode)
	{
		return $this->map[$hashCode];
	}
}

class State
{
	public $value;
	
	public function __construct()
	{
		$this->value=rand(0,111);
	}
}

class MyClass
{
	public $state;
	public $stateHash;
	
	public function __construct()
	{
		$this->changeState();
	}
	
	public function changeState()
	{
		$this->state=new State();
	}
	
	public function __sleep()
	{
		$this->stateHash=Identity::Instance()->hashCode($this->state);
		return array('stateHash');
	}
	
	public function __wakeup()
	{
		$this->state=Identity::Instance()->objectFromHashCode($this->stateHash);
	}
}

$object=new MyClass();
$clone=unserialize(serialize($object));

echo $object->state===$clone->state; //1