If I understand it correctly, that sentence actually refers to the piece of code above it, so I think "::" will confuse the reader (implying that the example will follow). 

That is why I also changed to "In the example above" instead of "In this example".

The code example above it:

class WidgetController extends AppController {

    public $components = array('Security');

    public function beforeFilter() {
        $this->Security->requirePost('delete');
    }
}

http://book.cakephp.org/2.0/en/core-libraries/components/security-component.html#usage

We can obviously just move the sentence to be above the example - it might be more readable...