java设计模式之---------------建造者模式

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建造者模式的原理就是一步步的建造复杂的对象。

/***
* 创建一个标识食物条目的接口
* @author gzl
*
*/
public interface Item {
   public String name();//名称
   public Packing packing();//包装
   public float price();//价格
}

/***
* 表示食物包装的接口
* @author gzl
*
*/
public interface Packing {
//该方法用于,定义Item类包装的名称
public String pack();
}

/***
* 创建包装类的具体实现类Bottle
* @author gzl
*
*/
public class Bottle implements Packing {
   @Override
   public String pack() {
       return "Bottle";
   }
}

/***
* 创建包装类的具体实现类Wrapper
* @author gzl
*
*/
public class Wrapper implements Packing {
   @Override
   public String pack() {
       return "Wrapper";
   }
}

/***
* 创建实现Item接口的抽象类Burger,该类只抽象出了包装方法
* @author gzl
*
*/
public abstract class Burger implements Item {
   @Override
   public Packing packing() {
       return new Wrapper();
   }
}

/***
* 创建实现Item接口的抽象类ColdDrink,该类只抽象出了包装方法
* @author gzl
*
*/
public abstract class ColdDrink implements Item {
   @Override
   public Packing packing() {
       return new Bottle();
   }
}

/***
* 创建扩展了Burger类的具体类ChickenBurger
* @author gzl
*
*/
public class ChickenBurger extends Burger {
   @Override
   public String name() {
       return "Chicken Burger";
   }
   @Override
   public float price() {
       return 50.5f;
   }
}

/***
* 创建扩展了Burger类的具体类VegBurger
* @author gzl
*
*/
public class VegBurger extends Burger {
   @Override
   public String name() {
       return "Veg Burger";
   }
   @Override
   public float price() {
       return 25.0f;
   }
}

public class Coke extends ColdDrink {
   @Override
   public String name() {
       return "Coke";
   }
   @Override
   public float price() {
       return 30.0f;
   }
}

public class Pepsi extends ColdDrink {
   @Override
   public String name() {
       return "Pepsi";
   }
   @Override
   public float price() {
       return 35.0f;
   }
}

/***
* 菜单类Meal
* @author gzl
*
*/
public class Meal {
   private List<Item> items = new ArrayList<Item>();

   public void addItem(Item item){
       items.add(item);
   }

   public float getCost(){
       float cost = 0.0f;
       for(Item item : items){
           cost += item.price();
       }
       return cost;
   }

   public void showItems(){
       for(Item item : items){
           System.out.println("Item:"+item.name());
           System.out.println(",Packing:"+item.packing().pack());
           System.out.println(",Price:"+item.price());
       }
   }
}

/***
* 菜单创建者类MealBuilder
* @author gzl
*
*/
public class MealBuilder {
   public Meal prepareVegMeal(){
       Meal meal = new Meal();
       meal.addItem(new VegBurger());
       meal.addItem(new Coke());
       return meal;
   }

   public Meal prepareNonVegMeal(){
       Meal meal = new Meal();
       meal.addItem(new ChickenBurger());
       meal.addItem(new Pepsi());
       return meal;
   }
}

/***
* 测试类
* @author gzl
*
*/
public class Test {
   public static void main(String[] args) {
       MealBuilder mealBuilder = new MealBuilder();
       Meal vegMeal = mealBuilder.prepareVegMeal();
       System.out.println("------>Veg Meal");
       vegMeal.showItems();
       System.out.println("Total Cost:"+vegMeal.getCost());

       Meal nonVegMeal = mealBuilder.prepareNonVegMeal();
       System.out.println("\n\n------>Non-Veg Meal");
       nonVegMeal.showItems();
       System.out.println("Total Cost:"+nonVegMeal.getCost());
   }
}

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