用哪种设计模式制作披萨

Answer 1

所有示例都是用Java编写的

tltr：向下滚动到生成器模式

例如，如果您有一个表示矩形的类，就会使用decorator模式。矩形类只有一个计算周长的方法。现在您要向矩形添加一个方法来计算面积。问题是，您既不能也不想编辑类矩形，因此创建了一个新类MySuperDuperRectangle，如下所示：

周边界面：

interface Perimeter{
    public int perimeter();
}

由于某种原因我们无法改变的矩形

class Rectange implements perimeter{
    private int a, b;

    public Rectange(int a, int b){
        this.a = a;
        this.b = b;
    }

    public int getA(){
        return a;
    }
    public int getB(){
        return b;
    }

    public int perimeter(){
        return 2 * a + 2 * b;
    }

}

装饰的矩形：

class MySuperDuperRectange implements perimeter{
    private Rectange r;

    public MySuperDuperRectange(Rectange r){
        this.r = r;
    }

    public int perimeter(){
        return r.perimeter();
    }

    public float area(){
        return r.getA() * r.getB();
    }

}

我将使用Builder模式，因为任务是构建比萨饼。

Builder模式用于构建后字按原样存在的东西（并且在任何时候都不应该被改变）。

PizzaBuiler的基本实现如下所示：

enum Dough{
    WHITE, BROWN
}

enum Cheese{
    WHITE, BROWN
}

顶部枚举：

enum Topping{
    Kittens, Onions, Salami
}

yummi披萨：

class Pizza{

    private Dough dough;
    private Cheese cheese;
    private HashSet<Topping> toppings;

    private Pizza(Dough dough, Cheese cheese, HashSet<Topping> toppings){
        this.dough = dough;
        this.cheese = cheese;
        this.toppings = toppings;
    }

    //add some getters

}

比萨布人：

class PizzaBuilder{

    private Dough dough;
    private Cheese cheese;
    private HashSet<Topping> toppings = new HashSet<Topping>();

    public PizzaBuilder(){

    }
    public PizzaBuilder setDough(Dough dough){
        this.dough = dough;
        return this;
    }
    public PizzaBuilder setCheese(Cheese cheese){
        this.cheese = cheese;
        return this;
    }
    public PizzaBuilder addTopping(Topping topping){
        this.toppings.add(topping);
        return this;
    }
    public Pizza buildPizza(){
        return new Pizza(this.dough, this.cheese, this.toppings);
    }

}

Pizza myPizza = new PizzaBuilder()
        .setDough(Dough.WHITE)
        .setCheese(Cheese.WHITE)
        .addTopping(Topping.Kittens)
        .addTopping(Topping.Salami)
        .buildPizza();