装饰器模式

// 手机接口
public interface Phone {
    // 功能
    void funcation();
}
--------------------

// 手机类
public class PhoneApp implements Phone {
    @Override
    public void funcation() {
        System.out.println("手机发短信");
    }
}

 public static void main(String[] args) {
        Phone phone = new PhoneApp();
        phone.funcation();
    }

// 实现手机接口
public abstract  class PhoneFunction implements Phone{
    public Phone phone;
    public PhoneFunction(Phone phone){
        this.phone = phone;
    }
}

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// 继承抽象类 重写funcation 方法
public class PhoneApp1 extends PhoneFunction {
    public PhoneApp1(Phone phone) {
        super(phone);
    }

    @Override
    public void funcation() {
        phone.funcation();
        System.out.println("手机打电话");
    }
}

   public static void main(String[] args) {
        Phone phone = new PhoneApp1(new PhoneApp());
        phone.funcation();
    }

public class PhoneApp2 extends PhoneFunction{
    public PhoneApp2(Phone phone) {
        super(phone);
    }

    @Override
    public void funcation() {
        phone.funcation();
        System.out.println("手机点外卖");
    }
}

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 public static void main(String[] args) {
        Phone phone = new PhoneApp2(new PhoneApp1(new PhoneApp()));
        phone.funcation();
    }