工厂模式、抽象工厂

/**
 * 最初的设计
 */
Pizza orderPizaa(String type){
    Pizza pizza;
    /*
     *此代码没有对修改封闭
     *压力来自于增加更多的比萨类型
     */
    if(type.equals("cheese")){
        pizza = new CheesePizza();
    } else if(type.equals("greek")){
        pizza = new GreekPizza();
    }  else if(type.equals("pepperoni")){
        pizza = new PepperoniPizza();
    }

    pizza.prepare();
    pizza.bake();
    pizza.cut();
    pizza.box();
    return pizza;
}
/**
 *建立一个简单工厂
 */
public class SimplePizzaFactory{
    public Pizza createPizza(String type){
        Pizza pizza = null;

        if(type.equals("cheese")){
            pizza = new CheesePizza();
        } else if(type.equals("greek")){
            pizza = new GreekPizza();
        }  else if(type.equals("pepperoni")){
            pizza = new PepperoniPizza();
        }
        return pizza;
    }
}

public class PizzaStore{
    SimplePizzaFactory factory;

    public PizzaStore(SimplePizzaFactory factory){
        this.factory = factory;
    }

    public Pizza orderPizaa(String type){
        Pizza pizza;
        pizza = fatory.createPizza(type);

        pizza.prepare();
        pizza.bake();
        pizza.cut();
        pizza.box();
        return pizza;
    }
}
/**
 *让比萨制作活动局限于PizzaStore类，而同时又能让这些加盟店依然可以自由地制作该区域的风味
 *工厂方法模式定义了一个创建对象的接口，但由子类决定要实例化的类是哪一个。工厂方法让类把实例化推迟到子类。
 */
public abstract class PizzaStore{
    
    public Pizza orderPizza(String type){
        Pizza pizza;

        pizza = createPizza(type);
        pizza.prepare();
        pizza.bake();
        pizza.cut();
        pizza.box();
            
        return pizza;
    }

    abstract Pizza createPizza(String type);
}
    /*
     * 开加盟店：纽约风味
     */
public class NYPizzaStore extends PizzaStore{

    Pizza createPizza(String item){
        if(type.equals("cheese")){
            pizza = new NYStyleCheesePizza();
        } else if(type.equals("greek")){
            pizza = new NYStyleGreekPizza();
        } else if(type.equals("pepperoni")){
            pizza = new NYStylePepperoniPizza();
        } else return null;
    }
}

public abstract class Pizza{
    String name;
    String dough;
    String sauce;
    ArrayList toppings = new ArrayList();
    
    void prepare(){
        System.out.println("Preparing "+name);
        ...
    }
    void bake(){
        System.out.println("Bake for 25 minutes at 350");
    }
}

public class NYStyleCheesePizza extends Pizza{
    public NYStyleCheesePizza(){
        name="NY Style Sauce and Cheese Pizza";
        dough = "Thin Crust Dough";
        sauce = "Marinara Sauce";

        toppings.add("Grated Reggiano Cheese");
    }
}

public class PizzaTestDrive{
    
    public static void main(String[] args){
        PizzaStore nyStore = new NYPizzaStore();
        Pizza pizza = nyStore.orderPizza("cheese");
    }
}

/**
 * 一个很依赖的比萨店
 */
public class DependentPizzaStore{
    
    public Pizza createPizza(String style, String type){
        if(style.equals("NY")){
            if(type.equals("cheese")){
                pizza = new NYStyleCheesePizza();
            } else if(type.equals("greek")){
                pizza = new NYStyleGreekPizza();
            } else if(type.equals("pepperoni")){
                pizza = new NYStylePepperoniPizza();
            }
        } else if(style.equals("Chicago")){
            if(type.equals("cheese")){
                pizza = new ChicagoStyleCheesePizza();
            } else if(type.equals("greek")){
                pizza = new ChicagoStyleGreekPizza();
            } else if(type.equals("pepperoni")){
                pizza = new ChicagoStylePepperoniPizza();
            }
        } else {
            System.out.println("Error: invalid type of pizza");
            return null;
        }

        pizza.prepare();
        pizza.bake();
        pizza.cut();
        pizza.box();
            
        return pizza;
    }
}
/*
 *设计原则：要依赖对象，不要依赖具体类。
 */

/**
 * 建造原料工厂
 */
public interface PizzaIngredientFactory{
    public Dough createDough();
    public Sauce createSauce();
    public Cheese createCheese();
    public Veggies[] createVeggies();
    public Pepperoni createPepperoni();
    public Clams createClam();
}
/**
 * 创建纽约原料工厂
 */
public class NYPizzaIngredientFactory implements PizzaIngredientFactory{
    public Dough createDough(){
        return new ThinCrustDough();
    }
    ...
}

/**
 * 重做比萨
 */
public abstract class Pizza{

    String name;
    Dough dough;
    Sauce sauce;
    ...

    abstract void prepare();

    void bake(){
        System.out.println("Bake for 25 minutes at 350");
    }

    ...
}

public class CheesePizza extends Pizza{
    PizzaIngredientFactory ingredientFactory;

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

    void prepare(){
        System.out.orintln("Preparing "+name);
        dough = ingredientFactory.createDough();
        sauce = ingredientFactory.createSauce();
        cheese = ingredientFactory.createCheese();
    }
}