趣解设计模式之《小王的披萨店续集》

爪哇缪斯

发布于 2023-10-06 12:39:10

1740

发布于 2023-10-06 12:39:10

〇、小故事

在《小王的披萨店》这篇文章中，我们介绍了小王开披萨店的故事，并且为了解决多种口味披萨的扩展问题，引出了简单工厂和工厂方法模式。但是，故事仍在继续，如果芝加哥的披萨店和纽约的披萨店，要求往披萨上面加的配料都不一样，那么如何可以规范多种类型披萨的创建呢？如下图所示：

【Dough】生面团 【Sauce】调味汁 【Cheese】干酪、奶酪 【Clams】蛤蜊

那么为了解决类似的问题，就可以采用我们今天要介绍的模式——抽象工厂模式。它解决了的是同一类型下多个产品族的创建。通过抽象工厂，组合了多种类型产品的创建（类似产品线）。

一、模式定义

抽象工厂模式（Abstract Factory Pattern）

提供一个接口，用于创建相关或依赖对象的家族，而不需要明确指定具体类。

二、模式类图

对于抽象工厂，将一系列产品（配料类型，比如：Dough、Sauce、Cheese、Clams）统一到一起去创建（即：PizzaIngredientFactory的实现类：NYPizzaingredientFactory和ChicagoPizzaingredientFactory）。PizzaIngredientFactory中的createDough()、createSauce()等方法，不关心底层配料如何实现，它只关系产品类型，不在意创建细节。具体类图，如下所示：

三、代码实现

奶酪原料及实现类：Cheese.java、MozzarellaCheese.java、ReggianoCheese.java

/** 奶酪接口 **/
public interface Cheese {
    void description();
}

/** 莫泽雷勒干酪 **/
public class MozzarellaCheese implements Cheese {
    public void description() {
        System.out.println("MozzarellaCheese");
    }
}

/** 帕尔玛奶酪 **/
public class ReggianoCheese implements Cheese {
    public void description() {
        System.out.println("ReggianoCheese");
    }
}

蛤蜊原料及实现类：Clams.java、FreshClams.java、FrozenClams.java

/** 蛤蜊接口 **/
public interface Clams {
    void description();
}

/** 新鲜蛤蜊 **/
public class FreshClams implements Clams{
    public void description() {
        System.out.println("FreshClams");
    }
}

/** 冷冻蛤蜊 **/
public class FrozenClams implements Clams{
    public void description() {
        System.out.println("FrozenClams");
    }
}

生面团原料及实现类：Dough.java、ThickCrustDough.java、ThinCrustDough.java

/** 生面团接口 **/
public interface Dough {
    void description();
}

/** 厚的面包皮生面团 **/
public class ThickCrustDough implements Dough {
    public void description() {
        System.out.println("ThickCrustDough");
    }
}

/** 薄的面包皮生面团 **/
public class ThinCrustDough implements Dough {
    public void description() {
        System.out.println("ThinCrustDough");
    }
}

调味汁原料及实现类：Sauce.java、MarinaraSauce.java、PlumTomatoSauce.java

/** 调味汁接口 **/
public interface Sauce {
    void description();
}

/** 番茄酱调味汁 **/
public class MarinaraSauce implements Sauce {
    public void description() {
        System.out.println("MarinaraSauce");
    }
}

/** 梅子西红柿调味汁 **/
public class PlumTomatoSauce implements Sauce {
    public void description() {
        System.out.println("PlumTomatoSauce");
    }
}

披萨原料抽象工厂及实现类：PizzaIngredientFactory.java、NYPizzaingredientFactory.java、ChicagoPizzaingredientFactory.java

/** 披萨原料抽象工厂 **/
public interface PizzaIngredientFactory {
    Dough createDough();
    Sauce createSauce();
    Cheese createCheese();
    Clams createClams();
}

/** 芝加哥原料工厂 **/
public class ChicagoPizzaingredientFactory implements PizzaIngredientFactory {
    public Dough createDough() {
        return new ThinCrustDough(); // 薄的面包皮生面团 
    }
    public Sauce createSauce() {
        return new MarinaraSauce(); // 番茄酱调味汁
    }
    public Cheese createCheese() {
        return new ReggianoCheese(); // 帕尔玛奶酪
    }
    public Clams createClams() {
        return new FreshClams(); // 新鲜蛤蜊
    }
}

/** 纽约原料工厂 **/
public class NYPizzaingredientFactory implements PizzaIngredientFactory {
    public Dough createDough() {
        return new ThickCrustDough(); // 厚的面包皮生面团
    }
    public Sauce createSauce() {
        return new PlumTomatoSauce(); // 梅子西红柿调味汁
    }
    public Cheese createCheese() {
        return new MozzarellaCheese(); // 莫泽雷勒干酪
    }
    public Clams createClams() {
        return new FrozenClams(); // 冷冻蛤蜊
    }
}

创建Pizza及实现类：Pizza.java

/** 披萨抽象类 **/
public abstract class Pizza {
    protected String name;
    protected Dough dough; // 面团
    protected Sauce sauce; // 酱
    protected Cheese cheese; // 干酪
    protected Clams clams; // 蛤蜊
    protected PizzaIngredientFactory pizzaIngredientFactory;

    /** 准备原材料 */
    public abstract void prepare();

    public void bake() {
        System.out.println("pizzaIngredientFactory bake()");
    }

    public void cut() {
        System.out.println("pizzaIngredientFactory cut()");
    }

    public void box() {
        System.out.println("pizzaIngredientFactory box()");
    }
}

奶酪口味披萨：CheesePizza.java

/** 奶酪口味披萨 **/
public class CheesePizza extends Pizza {

    public CheesePizza(PizzaIngredientFactory pizzaIngredientFactory) {
        this.pizzaIngredientFactory = pizzaIngredientFactory;
    }

    public void prepare() {
        System.out.println("CheesePizza prepare()");
        dough = pizzaIngredientFactory.createDough();
        sauce = pizzaIngredientFactory.createSauce();
        cheese = pizzaIngredientFactory.createCheese();
    }
}

蛤蜊口味披萨：ClamPizza.java

/** 蛤蜊口味披萨 **/
public class ClamPizza extends Pizza {

    public ClamPizza(PizzaIngredientFactory pizzaIngredientFactory) {
        this.pizzaIngredientFactory = pizzaIngredientFactory;
    }

    public void prepare() {
        System.out.println("ClamPizza prepare()");
        dough = pizzaIngredientFactory.createDough();
        sauce = pizzaIngredientFactory.createSauce();
        cheese = pizzaIngredientFactory.createCheese();
        // 加入蛤蜊配料
        clams = pizzaIngredientFactory.createClams();
    }
}

意大利辣肉肠口味披萨：PepperoniPizza.java

/**意大利辣肉肠口味披萨 **/
public class PepperoniPizza extends Pizza {

    public PepperoniPizza(PizzaIngredientFactory pizzaIngredientFactory) {
        this.pizzaIngredientFactory = pizzaIngredientFactory;
    }

    public void prepare() {
        System.out.println("PepperoniPizza prepare()");
        dough = pizzaIngredientFactory.createDough();
        sauce = pizzaIngredientFactory.createSauce();
        cheese = pizzaIngredientFactory.createCheese();
        // 加入蛤蜊配料
        clams = pizzaIngredientFactory.createClams();
    }
}

蔬菜口味披萨：VeggiePizza.java

/** 蔬菜口味披萨 **/
public class VeggiePizza extends Pizza {

    public VeggiePizza(PizzaIngredientFactory pizzaIngredientFactory) {
        this.pizzaIngredientFactory = pizzaIngredientFactory;
    }

    public void prepare() {
        System.out.println("VeggiePizza prepare()");
        dough = pizzaIngredientFactory.createDough();
        sauce = pizzaIngredientFactory.createSauce();
        cheese = pizzaIngredientFactory.createCheese();
    }
}

披萨工厂及实现类：PizzaStoreV3.java、NYPizzaStore.java

public abstract class PizzaStoreV3 {
    protected abstract Pizza createPizza(String pizzaType);

    public Pizza orderPizza(String pizzaType) {
        Pizza pizza = createPizza(pizzaType);
        pizza.prepare();
        pizza.bake();
        pizza.cut();
        pizza.box();
        return pizza;
    }
}

public class NYPizzaStore extends PizzaStoreV3 {
    protected Pizza createPizza(String pizzaType) {
        Pizza pizza = null;
        PizzaIngredientFactory pizzaIngredientFactory = new NYPizzaingredientFactory();
        if (pizzaType.equals("cheese")) {
            pizza = new CheesePizza(pizzaIngredientFactory);
        } else if (pizzaType.equals("pepperoni")) {
            pizza = new PepperoniPizza(pizzaIngredientFactory);
        } else if (pizzaType.equals("clam")) {
            pizza = new ClamPizza(pizzaIngredientFactory);
        } else if (pizzaType.equals("veggie")) {
            pizza = new VeggiePizza(pizzaIngredientFactory);
        }
        return pizza;
    }
}

抽象工厂测试类：PizzaStoreTest.java

public class PizzaStoreTest {
    public static void main(String[] args) {
        PizzaStoreV3 pizzaStore = new NYPizzaStore();
        pizzaStore.orderPizza("cheese");
    }
}