设计模式之四：工厂方法模式(披萨店生产披萨模拟流程)

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。(披萨店生产披萨模拟流程)

工厂方法模式通过让子类决定该创建的对象是什么，来达到将对象的过程封装的目地。

简单工厂和工厂方法之间的差异：

1）简单工厂不是一个设计模式，常被误认为是“工厂模式”。

2）简单工厂把全部的事情，在一个地方都处理完了，然而工厂方法却是创建一个框架，让子类决定要如何实现。

3）简单工厂的做法，可以将对象的创建封装起来，但是简单工厂具备工厂方法的弹性，因为简单工厂不能变更正在创建的产品。

工程名称：Factory      下载目录：http://www.cnblogs.com/jrsmith/admin/Files.aspx     ，Factory.zip

package com.jyu.store;

import com.jyu.pizza.Pizza;

/**
 * 抽象 批萨店 类
 * @author root
 *
 */
public abstract class PizzaStore {

    public Pizza orderPizza(String type){
        Pizza pizza;
        
        pizza = createPizza(type);
        
        pizza.prepare();
        pizza.bake();
        pizza.cut();
        pizza.box();
        
        return pizza;
    }
    
    /**
     * 生产具体类型批萨工厂
     * @param type
     * @return
     */
    public abstract Pizza createPizza(String type);
}

package com.jyu.newyostore;

import com.jyu.newyopizza.NYStyleCheesePizza;
import com.jyu.newyopizza.NYStyleClamPizza;
import com.jyu.newyopizza.NYStylePepperoniPizza;
import com.jyu.newyopizza.NYStyleVeggiePizza;
import com.jyu.pizza.Pizza;
import com.jyu.store.PizzaStore;

/**
 * 纽约批萨店
 * @author root
 *
 */
public class NYPizzaStore extends PizzaStore {

    @Override
    public Pizza createPizza(String type) {
        
        if(type.equals("cheese")){
            return new NYStyleCheesePizza();
        }else if(type.equals("veggie")){
            return new NYStyleVeggiePizza();
        }else if(type.equals("clam")){
            return new NYStyleClamPizza();
        }else if(type.equals("pepperoni")){
            return new NYStylePepperoniPizza();
        }else{
            return null;
        }
    }

}

package com.jyu.chigagostore;

import com.jyu.chigagopizza.ChicagoStyleCheesePizza;
import com.jyu.chigagopizza.ChicagoStyleVeggiePizza;
import com.jyu.pizza.Pizza;
import com.jyu.store.PizzaStore;

/**
 * 芝加哥批萨店
 * @author root
 *
 */
public class CGPizzaStore extends PizzaStore {

    @Override
    public Pizza createPizza(String type) {
        
        if(type.equals("cheese")){
            return new ChicagoStyleCheesePizza();
        }else if(type.equals("veggie")){
            return new ChicagoStyleVeggiePizza();
        }else{
            return null;
        }
    }

}

package com.jyu.pizza;

import java.util.ArrayList;

/**
 * 抽象 批萨类
 * @author root
 *
 */
public abstract class Pizza {

    protected String name;
    protected String dough;
    protected String sauce;
    protected ArrayList toppings = new ArrayList();
    
    /**
     * 基本做法：烘烤，切片，装盒
     */
    public void prepare(){
        System.out.println("Preparing " + name);
        System.out.println("Tossin dough...");
        System.out.println("Adding sauce..");
        System.out.println("Adding toppings: ");
        for(int i = 0; i < toppings.size(); i++){
            System.out.println("  " + toppings.get(i));
        }
    }
    
    public void bake(){
        System.out.println("Bake for 25 minutes at 350");
    }
    
    public void cut(){
        System.out.println("Cutting the pizza into diagonal slices");
    }
    
    public void box(){
        System.out.println("Place pizza in offical PizzaStore box");
    }
    
    public String getName(){
        return name;
    }
}

package com.jyu.newyopizza;

import com.jyu.pizza.Pizza;

/**
 * 纽约Cheese批萨
 * @author root
 *
 */
public class NYStyleCheesePizza extends Pizza {
    
    @SuppressWarnings("unchecked")
    public NYStyleCheesePizza(){
        name = "NY Style Sauce and Cheese Pizza";
        dough = "Thin Crust Dough";
        sauce = "Marinara Sauce";
        
        toppings.add("Grated Reggiano Cheese");
    }
}

package com.jyu.newyopizza;

import com.jyu.pizza.Pizza;

/**
 * 纽约Clam批萨
 * @author root
 *
 */
public class NYStyleClamPizza extends Pizza {
    
    @SuppressWarnings("unchecked")
    public NYStyleClamPizza(){
        name = "NY Style ClamPizza";
        dough = "NYStyleClamPizza Dough";
        sauce = "NYStyleClamPizza Sauce";
        
        toppings.add("Grated Reggiano Clam");
    }
}

package com.jyu.newyopizza;

import com.jyu.pizza.Pizza;

/**
 * 纽约Pepperoni批萨
 * @author root
 *
 */
public class NYStylePepperoniPizza extends Pizza {
    
    @SuppressWarnings("unchecked")
    public NYStylePepperoniPizza(){
        name = "NY Style Pepperoni";
        dough = "NYStylePepperoniPizza Dough";
        sauce = "NYStylePepperoniPizza Sauce";
        
        toppings.add("Grated Reggiano Pepperoni");
    }
}

package com.jyu.newyopizza;

import com.jyu.pizza.Pizza;

/**
 * 纽约Veggie批萨
 * @author root
 *
 */
public class NYStyleVeggiePizza extends Pizza {
    
    @SuppressWarnings("unchecked")
    public NYStyleVeggiePizza(){
        name = "NY Style VeggiePizza";
        dough = "NYStyleVeggiePizza Dough";
        sauce = "NYStyleVeggiePizza Sauce";
        
        toppings.add("Grated Reggiano Veggie");
    }
}

package com.jyu.chigagopizza;

import com.jyu.pizza.Pizza;

/**
 * 芝加哥Cheese批萨
 * @author root
 *
 */
public class ChicagoStyleCheesePizza extends Pizza {
    
    @SuppressWarnings("unchecked")
    public ChicagoStyleCheesePizza(){
        name = "Chicago Style Sauce and Cheese Pizza";
        dough = "Extra Thick Crust Dough";
        sauce = "Plum Tomato Sauce";
        
        toppings.add("Shredded Mozzarella Cheese");
    }
    
    @Override
    public void cut(){
        System.out.println("Cutting the pizza into square slices");
    }
    
}

package com.jyu.chigagopizza;

import com.jyu.pizza.Pizza;

/**
 * 芝加哥Veggie批萨
 * @author root
 *
 */
public class ChicagoStyleVeggiePizza extends Pizza {
    
    @SuppressWarnings("unchecked")
    public ChicagoStyleVeggiePizza(){
        name = "Chicago Style VeggiePizza";
        dough = "ChicagoStyleVeggiePizza Dough";
        sauce = "ChicagoStyleVeggiePizza Sauce";
        
        toppings.add("Shredded Mozzarella Veggie");
    }
    
    @Override
    public void cut(){
        System.out.println("Cutting the pizza into square slices");
    }
    
}

package com.jyu.test;

import com.jyu.chigagostore.CGPizzaStore;
import com.jyu.newyostore.NYPizzaStore;
import com.jyu.pizza.Pizza;
import com.jyu.store.PizzaStore;

public class PizzaTestDrive {

    /**
     * @param args
     */
    public static void main(String[] args) {

        PizzaStore nyStore = new NYPizzaStore();
        PizzaStore chicagoStroe = new CGPizzaStore();
        
        Pizza pizza = nyStore.orderPizza("cheese");
        System.out.println("Ethan ordered a " + pizza.getName() + "\n");
        
        pizza = chicagoStroe.orderPizza("cheese");
        System.out.println("Joel ordered a " + pizza.getName() + "\n");
    }

}