外观模式

外观模式隐藏了系统的的复杂性，为客户端提供一个可以访问系统的接口，由接口决定访问系统的哪些功能，以及怎么访问，客户端可以完全不了解系统的内部情况，方便系统的内部拓展和维护。示例如下：

public class Exterior {
    public static void main(String[] args){
        Exterior exterior = new Exterior();
        Receptionist receptionist0=exterior.new Receptionist("没病多疑");
        receptionist0.noDisease();
        Receptionist receptionist1=exterior.new Receptionist("小病");
        receptionist1.lightDisease();
        Receptionist receptionist2=exterior.new Receptionist("重病");
        receptionist2.weightyDisease();
    }

    class Outpatient{
        public void work(){
            System.out.println("门诊");
        }
    }

    class Register{
        public void work(){
            System.out.println("挂号");
        }
    }

    class Payment{
        public void work(){
            System.out.println("缴费");
        }
    }

    class Medicine{
        public void work(){
            System.out.println("取药");
        }
    }

    class Surgery{
        public void work(){
            System.out.println("手术");
        }
    }

    class Receptionist{
        private Register register;
        private Outpatient outpatient;
        private Payment payment;
        private Medicine medicine;
        private Surgery surgery;
        private String type;

        public Receptionist(String type) {
            this.type = type;
            register=new Register();
            outpatient=new Outpatient();
            payment=new Payment();
            medicine=new Medicine();
            surgery=new Surgery();
        }

        public void noDisease(){
            showType();
            register.work();
            outpatient.work();

        }
        public void lightDisease(){
            showType();
            register.work();
            outpatient.work();
            payment.work();
            medicine.work();
        }
        public void weightyDisease(){
            showType();
            register.work();
            outpatient.work();
            payment.work();
            medicine.work();
            surgery.work();
        }

        private void showType(){
            System.out.println(type);
        }
    }
}