add_action in wordpress using OOP?

[admin]

I am learning about OOP, and I think I am getting the hang of it. My question is why the author of a wordpress boilerplate plugin wrote the add action function like this

add_action('admin_init', array(&$this, 'admin_init'));

According to the codex I understand the

add_action

hook, the paramaters to be passed are

$tag

"The name of the action to which $function_to_add is hooked", and the function that you want hooked

$function_to_add

.

Well I understand the functions in OOP are methods, and I can see why that may change the syntax, but that is just a vague representation, I want a clear answer why the author uses an array, then uses

&$this

. I understand why one would use

$this->property

but not so sure about

&$this

.

Is it just how you refer to the method? If so I still dont understand the array, why wouldnt it look something like

$this->admin_init

.

By the way the structure looks kind of like this

    class my_plugin_settings {

            public function __construct() {

                    // register actions
                    add_action('admin_init', array(&$this, 'admin_init'));

            } 

            public function admin_init() {

                    //Settings here
            }
    }