Object Oriented Programming in ACL

[nettrinity]

Dear friends,
The below code "extends" and "implements" at the same time from two different classes.
How could this be possible? I am confused! Where can I find materials to explain this OO concept?

Thank you!
Nicolas Xu




class Storefront_Model_Acl_Storefront extends Zend_Acl implements
SF_Acl_Interface
{
public function __construct()
{
$this->addRole(new Storefront_Model_Acl_Role_Guest)
->addRole(new Storefront_Model_Acl_Role_Customer, 'Guest')
->addRole(new Storefront_Model_Acl_Role_Admin, 'Customer');
$this->deny();
}
}

[nettrinity]

Please help me take a look at this crazy class! It implements and extends 3 classes! What's really going on here? Does it just combine them all?


class Storefront_Resource_User_Item extends SF_Model_Resource_Db_Table_Row_Abstract implements
Storefront_Resource_User_Item_Interface, Zend_Acl_Role_Interface
{
   /*... */
   public function getRoleId()
   {
       if (null === $this->getRow()->role) {
       return 'Guest';
       }
       return $this->getRow()->role;
   }
}

[weierophinney]

-- nettrinity <[hidden email]> wrote
(on Saturday, 12 March 2011, 02:07 PM -0800):
> Please help me take a look at this crazy class! It implements and extends 3
> classes! What's really going on here? Does it just combine them all?

You need to read up on interfaces and extension in PHP:

    http://php.net/oop

Basically, you can extend a single class, which allows you to inherit
any defined methods, variables, or constants from that class. However,
you can _implement_ as many interfaces as you want. An interface
declares one or more public methods that _must_ be defined in a concrete
implementation. If you class implements several interfaces, it must then
implement the methods defined in each of those interfaces.

In the example below, getRoleId() is declared within
Zend_Acl_Role_Interface, and thus implemented in this particular class.

> class Storefront_Resource_User_Item extends
> SF_Model_Resource_Db_Table_Row_Abstract implements
> Storefront_Resource_User_Item_Interface, Zend_Acl_Role_Interface
> {
>    /*... */
>    public function getRoleId()
>    {
>        if (null === $this->getRow()->role) {
>        return 'Guest';
>        }
>        return $this->getRow()->role;
>    }
> }

--
Matthew Weier O'Phinney
Project Lead            | [hidden email]
Zend Framework          | http://framework.zend.com/
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