大话设计模式-装饰模式

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需求
开发一个类似于QQ的服饰搭配系统。
实现
级别1

//person类代码  public class Person  {      private String name;      public Person(String name)      {          this.name = name;      }      public void wearTShirts()      {          System.out.println("大T恤");      }      public void wearBigTrouser()      {          System.out.println("大裤衩");      }      public void wearSneakers()      {          System.out.println("破球鞋");      }      public void wearSuit()      {          System.out.println("西装");      }      public void wearTie()      {          System.out.println("领带");      }      public void wearLeatherShoes()      {          System.out.println("皮鞋");      }      public void show()      {          System.out.println("装扮的" + name);      }  }  

//客户端代码 public class Main  {      public static void main(String[] args)      {          Person person = new Person("小菜");          System.out.println("第一种装扮:");          person.wearTShirts();          person.wearBigTrouser();          person.wearSneakers();          person.show();          System.out.println("第二种装扮:");          person.wearSuit();          person.wearTie();          person.wearLeatherShoes();          person.show();      }  }  

级别2

//Person类  public class Person  {      private String  name;        public Person(String name)      {          this.name = name;      }      public void show()      {          System.out.println("装扮的" + name);      }  }  

//服饰抽象类  public interface Finery  {      public void show();  }  

public class TShirts implements Finery  {      public void show()      {          System.out.println("大T恤");      }  }

public class BigTrouser implements Finery  {      public void show()      {          System.out.println("大裤衩");      }  }  

public class Sneakers implements Finery  {      public void show()      {          System.out.println("破球鞋");      }  } 

public class Suit implements Finery  {      public void show()      {          System.out.println("西装");      }  }  

public class Tie implements Finery  {      public void show()      {          System.out.println("领带");      }  }  

public class LeatherShoes implements Finery  {      public void show()      {          System.out.println("皮鞋");      }  } 

//客户端代码  public class Main  {      public static void main(String[] args)      {          Person person = new Person("小菜");          System.out.println("第一种装扮:");          Finery dtx = new TShirts();          Finery kk = new BigTrouser();          Finery pqx = new Sneakers();          dtx.show();          kk.show();          pqx.show();          person.show();          System.out.println("第二种装扮:");          Finery xz = new Suit();          Finery ld = new Tie();          Finery px = new LeatherShoes();          xz.show();        ld.show();          px.show();          person.show();      }  }  

级别3
装饰模式能够动态地给一个对象添加一些额外的职责，就增加功能来说，装饰模式比生成子类更为灵活。java的IO流就是典型的装饰模式。
装饰模式的基本代码：

//Component接口  public interface Component  {      public void operation();  }  //ConcreteComponent类  public class ConcreteComponent implements Component  {      public void operation()      {          System.out.println("具体对象的操作");      }  }  //Decorator类  public class Decorator implements Component  {      protected Component component;      public void operation()      {          if (null != component)          {              component.operation();          }      }      public Component getComponent()      {          return component;      }      public void setComponent(Component component)      {          this.component = component;      }  }  //装饰类  public class ConcreteDecoratorA extends Decorator  {      private String addedState;      public void operation()      {          super.operation();          addedState="new state";          System.out.println("具体装饰对象A的操作");      }  }  public class ConcreteDecoratorB extends Decorator  {      public void operation()      {          super.operation();          addedBehavior();          System.out.println("具体装饰对象B的操作");      }      private void addedBehavior()      {      }  }  //客户端代码  public class Main  {      public static void main(String[] args)      {          ConcreteComponent c = new ConcreteComponent();          ConcreteDecoratorA d1 = new ConcreteDecoratorA();          ConcreteDecoratorB d2 = new ConcreteDecoratorB();          d1.setComponent(c);          d2.setComponent(d1);          d2.operation();      }  }

按照装饰模式修改后的代码：

//Person类（ConcreteComponent）  public class Person  {      private String name;      public Person()      {      }      public Person(String name)      {          this.name = name;      }      public void show()      {          System.out.println("装扮的" + name);      }  } 

//服饰类（Decorator）  public class Finery extends Person  {      protected Person component;      public void decorate(Person component)      {          this.component = component;      }      public void show()      {          if (null != component)          {              component.show();          }      }  }

public class TShirts extends Finery  {      public void show()      {          super.show();          System.out.println("大T恤");      }  }

public class BigTrouser extends Finery  {      public void show()      {          super.show();          System.out.println("大裤衩");      }  }  

public class Sneakers extends Finery  {      public void show()      {          super.show();          System.out.println("破球鞋");      }  }  

public class Suit extends Finery  {      public void show()      {          super.show();          System.out.println("西装");      }  }  

public class Tie extends Finery  {      public void show()      {          super.show();          System.out.println("领带");      }  }

public class LeatherShoes extends Finery  {      public void show()      {          super.show();          System.out.println("皮鞋");      }  }

//客户端代码  public class Main  {      public static void main(String[] args)      {          Person person = new Person("小菜");          System.out.println("第一种装扮：");            Sneakers pqx = new Sneakers();          BigTrouser kk = new BigTrouser();          TShirts dtx = new TShirts();          pqx.decorate(person);          kk.decorate(pqx);          dtx.decorate(kk);          dtx.show();          System.out.println("第二种装扮：");          LeatherShoes px = new LeatherShoes();          Tie ld = new Tie();          Suit xz = new Suit();          px.decorate(person);          ld.decorate(px);          xz.decorate(ld);          xz.show();      }  }

我们再举一个例子。现在需要一个汉堡，主体是鸡腿堡，可以选择添加生菜、酱、辣椒等等许多其他的配料，这种情况下就可以使用装饰者模式。
汉堡基类：

public abstract class Humburger {            protected  String name;      public String getName()    {          return name;      }        public abstract double getPrice();  }  

鸡腿堡类：

public class ChickenBurger extends Humburger{            public ChickenBurger()    {          name = "鸡腿堡";      }      @Override      public double getPrice()     {          return 10;      }  }  

配料的基类：

public abstract class Condiment extends Humburger{            public abstract String getName();  }

生菜类：

public class Lettuce extends Condiment {            Humburger humburger;         public Lettuce(Humburger humburger)    {          this.humburger = humburger;      }      @Override      public String getName()     {          return humburger.getName()+" 加生菜";      }      @Override      public double getPrice()     {          return humburger.getPrice()+1.5;      }  } 

辣椒类：

public class Chilli extends Condiment{            Humburger humburger;         public Chilli(Humburger humburger)    {          this.humburger = humburger;                }      @Override      public String getName()     {          return humburger.getName()+" 加辣椒";      }      @Override      public double getPrice()    {          return humburger.getPrice();      }  }

测试一下：

public class Main{         public static void main(String[] args)    {          Humburger humburger = new ChickenBurger();          System.out.println(humburger.getName()+"  价钱："+humburger.getPrice());          Lettuce lettuce = new Lettuce(humburger);          System.out.println(lettuce.getName()+"  价钱："+lettuce.getPrice());          Chilli chilli = new Chilli(humburger);          System.out.println(chilli.getName()+"  价钱："+chilli.getPrice());          Chilli chilli2 = new Chilli(lettuce);          System.out.println(chilli2.getName()+"  价钱："+chilli2.getPrice());      }  }