Design patterns 在这个例子中,装饰器模式真的有必要吗?
这是问题陈述 一家餐厅有4个比萨饼基地: 全麦比萨饼Design patterns 在这个例子中,装饰器模式真的有必要吗?,design-patterns,Design Patterns,这是问题陈述 一家餐厅有4个比萨饼基地: 全麦比萨饼 木火比萨饼 奶酪馅饼 薄皮比萨饼 有8种浇头: 西红柿,洋葱,奶酪,辣椒,大蒜,土豆 计算给定一个比萨底面和0个或多个配料的比萨价格(假设每个底面和配料都配置了一些价格) 我的伪代码解决方案是: public class Pizza { public int getPrice(base, String... toppings){ PizzaBaseMap.get(base) + toppings
木火比萨饼
奶酪馅饼
薄皮比萨饼 有8种浇头: 西红柿,洋葱,奶酪,辣椒,大蒜,土豆 计算给定一个比萨底面和0个或多个配料的比萨价格(假设每个底面和配料都配置了一些价格) 我的伪代码解决方案是:
public class Pizza {
public int getPrice(base, String... toppings){
PizzaBaseMap.get(base) + toppingsMap.sum(t -> toppingsMap.get(t))
}
Hashmap<String, int> PizzaBaseMap= {
whole_wheat : 1
wood_fire : 2
cheese_filled : 2
thin_crust : 4
}
Hashmap<String, int> toppingsMap = {
tomato : 1
onion : 2
cheese : 4
pepporoni : 5
capsicum : 2
garlic : 2
paneer : 4
potato : 4
}
//client Code
int Price = new Pizza().getPrice("whole_wheat", ["tomato", "cheese"])
公共级比萨饼{
public int getPrice(基本、字符串…顶部){
PizzaBaseMap.get(base)+toppingsMap.sum(t->toppingsMap.get(t))
}
Hashmap PizzaBaseMap={
全麦:1
木火:2
奶酪馅:2
薄壳:4
}
Hashmap toppingsMap={
番茄:1
洋葱:2
奶酪:4
佩波罗尼:5
辣椒:2
大蒜:2
paneer:4
土豆:4
}
//客户端代码
int Price=new Pizza().getPrice(“全麦”、“西红柿”、“奶酪”)
我真的需要像Headfirst desgin模式手册在其示例中建议的那样使用装饰器吗?使用装饰器模式的解决方案如下所示:
public interface iPizza
{
double cost();
}
//Decorator
public interface iToppingDecorator:iPizza
{
}
//Pizza types
class WholeWheatPizza:iPizza
{
public double cost()
{
}
}
class WoodFire : iPizza
{
public double cost()
{
}
}
class CheeseFilled : iPizza
{
public double cost()
{
}
}
class Thincrust : iPizza
{
public double cost()
{
}
}
//Toppings inheriting Decorator Interface
class CheeseTopping:iToppingDecorator
{
iPizza pizza;
public CheeseTopping(iPizza pizzatype)
{
this.pizza = pizzatype;
}
public double cost()
{
return <price> + pizza.cost();
}
}
class TomatoTopping:iToppingDecorator
{
iPizza pizza;
public TomatoTopping(iPizza pizzatype)
{
this.pizza = pizzatype;
}
public double cost()
{
return <price> + pizza.cost();
}
}
class OnionTopping:iToppingDecorator
{
iPizza pizza;
public OnionTopping(iPizza pizzatype)
{
this.pizza = pizzatype;
}
public double cost()
{
return <price> + pizza.cost();
}
}
class PepporoniTopping:iToppingDecorator
{
iPizza pizza;
public PepporoniTopping(iPizza pizzatype)
{
this.pizza = pizzatype;
}
public double cost()
{
return <price> + pizza.cost();
}
}
class CapsicumTopping:iToppingDecorator
{
iPizza pizza;
public CapsicumTopping(iPizza pizzatype)
{
this.pizza = pizzatype;
}
public double cost()
{
return <price> + pizza.cost();
}
}
class PaneerTopping:iToppingDecorator
{
iPizza pizza;
public PaneerTopping(iPizza pizzatype)
{
this.pizza = pizzatype;
}
public double cost()
{
return <price> + pizza.cost();
}
}
class GarlicTopping:iToppingDecorator
{
iPizza pizza;
public GarlicTopping(iPizza pizzatype)
{
this.pizza = pizzatype;
}
public double cost()
{
return <price> + pizza.cost();
}
}
class PotatoTopping:iToppingDecorator
{
iPizza pizza;
public PotatoTopping(iPizza pizzatype)
{
this.pizza = pizzatype;
}
public double cost()
{
return <price> + pizza.cost();
}
}
//client
static void Main()
{
iPizza pizza1 = new WholeWheatPizza();
pizza1 = new CheeseTopping(pizza1);
Console.WriteLine("Pizza 1 cost: "+pizza1.cost()+"INR");
iPizza pizza2 = new WoodFire();
pizza2 = new CheeseTopping(pizza2);
pizza2 = new TomatoTopping(pizza2);
Console.WriteLine("Pizza 2 cost: " + pizza2.cost() + "INR");
Console.ReadLine();
}
公共接口iPizza
{
双重成本();
}
//装饰师
公共接口iToppingDecorator:iPizza
{
}
//比萨饼类型
全班披萨:iPizza
{
公共双重成本()
{
}
}
木火类:伊皮扎
{
公共双重成本()
{
}
}
奶酪类:iPizza
{
公共双重成本()
{
}
}
类Thincrust:iPizza
{
公共双重成本()
{
}
}
//继承装饰器接口的浇头
奶酪类:iToppingDecorator
{
伊皮萨比萨饼;
公共芝士店(iPizza Pizza型)
{
this.pizza=pizzatype;
}
公共双重成本()
{
return+pizza.cost();
}
}
TomatoToping类:iToppingDecorator
{
伊皮萨比萨饼;
公共番茄酱(iPizza比萨型)
{
this.pizza=pizzatype;
}
公共双重成本()
{
return+pizza.cost();
}
}
类OnOnOnToping:iToppingDecorator
{
伊皮萨比萨饼;
公共洋葱盖(iPizza pizzatype)
{
this.pizza=pizzatype;
}
公共双重成本()
{
return+pizza.cost();
}
}
PEPPORONTIPTING类:ITOPPINGDECOCTOR
{
伊皮萨比萨饼;
公共Pepporonitating(iPizza Pizza型)
{
this.pizza=pizzatype;
}
公共双重成本()
{
return+pizza.cost();
}
}
等级:iToppingDecorator
{
伊皮萨比萨饼;
公共浇头(iPizza Pizza型)
{
this.pizza=pizzatype;
}
公共双重成本()
{
return+pizza.cost();
}
}
类别PaneerTopping:iToppingDecorator
{
伊皮萨比萨饼;
公共PaneerTopping(iPizza Pizza类型)
{
this.pizza=pizzatype;
}
公共双重成本()
{
return+pizza.cost();
}
}
分类:iToppingDecorator
{
伊皮萨比萨饼;
公共大蒜头(iPizza Pizza型)
{
this.pizza=pizzatype;
}
公共双重成本()
{
return+pizza.cost();
}
}
PotatoTopping类:iToppingDecorator
{
伊皮萨比萨饼;
公共PotatoTopping(iPizza pizzatype)
{
this.pizza=pizzatype;
}
公共双重成本()
{
return+pizza.cost();
}
}
//客户
静态void Main()
{
iPizza pizza1=新的全热比萨饼();
pizza1=新奶酪配料(pizza1);
Console.WriteLine(“pizza1成本:+pizza1.cost()+INR”);
iPizza pizza2=新的WoodFire();
pizza2=新奶酪配料(pizza2);
pizza2=新番茄顶(pizza2);
Console.WriteLine(“pizza2成本:+pizza2.cost()+INR”);
Console.ReadLine();
}
我只是觉得这是一个完全的杀伤力,我的代码和使用decorator模式的解决方案一样具有可扩展性。有什么想法吗?是的,在这种情况下,这可能是杀伤力过大。但是,想象一下一个更大的应用程序,有更多的浇头;或者价格修饰符更复杂;或者您正在构建一个可重用的库 在这些情况下,decorator模式有两个优点:
foreach (var topping in toppings)
if (topping is Anchovies)
price := price * 0.8
else
price := price - toppingCosts[topping]
使用decorator模式,我们只需添加一个新类:
class AnchoviesToppingDecorator : IPizzaToppingDecorator
{
private IPizza pizza;
public AnchoviesTopping(IPizza pizza)
{
this.pizza = pizza;
}
public double cost()
{
return this.pizza.Cost() * 0.8f;
}
}
当然,decorator应用程序的顺序变得很重要。如果需要,可以使用类型系统来强制执行
你可以强制执行命令
interface IPizzaToppingDecorator : IPizzaDecorator
{
}
interface IPizzaDiscountDecorator : IPizzaDecorator
{
}
public class HalfPriceDecorator : IPizzaDiscountDecorator
{
private IPizzaToppingDecorator pizzaToppingDecorator;
public HalfPriceDecorator(IPizzaToppingDecorator pizzaToppingDecorator)
{
this.pizzaToppingDecorator = pizzaToppingDecorator;
}
public double Cost()
{
pizzaToppingDecorator.Cost() * 0.5;
}
}
new WholeWheatPizza().WithTomatoTopping().WithCheeseTopping().WithPepporoniTopping();
public static IPizza WithCheeseTopping(this IPizza pizza)
{
return new CheeseToppingDecorator(pizza)
}