A way of accessing private fields in PHP is by changing the accessibility of the fields themselves with http://php.net/manual/en/reflectionproperty.setaccessible.php.
However this approach requires PHP 5.3.
For PHP < 5.3 there's another subtle way of accessing private properties:
Usage is pretty straightforward, pass in the object and the property name as string. The property must be private and must be convertible to array.