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Posted by Rik Wasmus on 10/14/07 14:12
On Sun, 14 Oct 2007 15:42:25 +0200, Thomas Mlynarczyk =
<thomas@mlynarczyk-webdesign.de> wrote:
>> But how to create a pizza with 2 toppings ??
>
> I would do something like this:
>
> interface NotForFree { function getPrice(); }
> class Pizza implements NotForFree { ... }
> class Margherita extends Pizza { ... }
> class Topping implements NotForFree { ... }
> class CheeseTopping extends Topping { ... ]
> class OnionTopping extends Topping { ... }
>
> $pizza =3D new Margherita;
> $pizza->addTopping( new CheeseTopping );
> $pizza->addTopping( new OnionsTopping );
> $pizza->getPrice();
>
> /* or */
>
> $pizza =3D new Margherita( new CheeseTopping, new OnionsTopping );
> $pizza->getPrice();
I'd definitely make Pizza a class and not an interface indeed. Then just=
a =
properly executed Decorator Pattern can set, and tell you exactly what =
type, toppings and total price this particular pizza would have. I would=
=
not recommend making 'Margherita','CheeseTopping' etc. hardcoded classes=
.. =
Unless it remains static after development, it would be a maintenance =
nightmare to add/remove/alter different kinds of pizza & toppings. I =
assume come kind of interface that gives options for Pizza & Toppings =
would be involved, which would mean that any alteration in those require=
s =
altering code & data in several places.
Rather, I'd have a database with a Pizzas table, including name & price,=
=
and a Toppings table, including name & price, and just a 'generic' Pizza=
=
object with the type/name/price in a variable, and either 'decorated' =
using the Decorator Pattern with generic Topping objects (which themselv=
es =
hold a toppingtype/toppingprice), or just an array of toppings in the =
Pizza class itself, so you could do a:
class Pizza{
...
public function getPrice(){
$price =3D $this->_price;
if(!empty($this->_toppings){
foreach($this->_toppings as &$topping){
$price +=3D $topping->getPrice();
}
}
return $price
}
...
}
... which hardly is any complicated pattern but gets the job done easily.=
=
As long as 'toppings' don't have any profound impact on the 'Pizza' othe=
r =
then price and actually being added as topping I'd choose this. If they =
=
have other impacts, like changing the output of Pizza::getRecipe(), =
Pizza::getBoxSize(), Pizza::getCalories() the Decorator Pattern would =
certainly pay out.
-- =
Rik Wasmus
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