装饰模式

一.作用：动态的给一个对象添加额外的功能。

二.代码

1.被装饰的接口Person

package design.decorator;

public interface Person {
    void eat();
}

2.Person接口的多种实现Man和Woman

package design.decorator;

public class Man implements Person{

    @Override
    public void eat() {
        // TODO Auto-generated method stub
        System.out.println("一个男人在吃饭...");
    }

}

package design.decorator;

public class Woman implements Person{

    @Override
    public void eat() {
        // TODO Auto-generated method stub
        System.out.println("一个女人在吃饭...");
    }

}

3.抽象的装饰器类Decorator来装饰接口Person，这样的话不同的装饰器抽象类的实现类就可以装饰任意Person接口的实现类

package design.decorator;

public abstract class Decorator implements Person {
    private Person person;
    public void setPerson(Person person){
        this.person = person;
    }
    
    public void eat(){
        person.eat();
    }
}

3.抽象装饰器类A和B

package design.decorator;

public class PersonDecoratorA extends Decorator{

    public void eat(){
        washHand();
        super.eat();
        washHand();
    }
    
    public void washHand(){
        System.out.println("洗手。。");
    }
}

package design.decorator;

public class PersonDecoratorB extends Decorator{
    public void eat(){
        stealEat();
        super.eat();
    }
    
    public void stealEat(){
        System.out.println("偷吃。。");
    }
}

4.测试：用装饰器A装饰Woman，装饰器B装饰Man

package design.decorator;

public class Test {
    public static void main(String[] args) {
        Man man = new Man();
        Woman woman = new Woman();
        PersonDecoratorA mda = new PersonDecoratorA();
        PersonDecoratorB mdb = new PersonDecoratorB();
        mda.setPerson(woman);
        mda.eat();
        System.out.println("-------------------------");
        mdb.setPerson(man);
        mdb.eat();
    }
}

5.结果

洗手。。
一个女人在吃饭...
洗手。。
-------------------------
偷吃。。
一个男人在吃饭...