22-04-11-비지터패턴-1부-패턴소개

public interface Device{
}

public Phone implements Device{
}

public Watch implements Device{
}

public class Client{
    public static void main(String[] args)
    {
        Shape rectangle = new Rectangle();
        rectangle.printTo(new Phone());
	}
}

public interface Shape {
    void printTo(Device device);
}// 모든 디바이스에 쓰기 위함

public class Rectangle implements Shape{
	@Override
    public void printTo(Device device){
        if(device instanceof Phone){
            System.out.println("print Rectangle to Phone");
        }else if(device instanceof Watch){
            System.out.println("print Rectangle to Watch");
        }
    }
}

public class Triangle implements Shape{
	@Override
    public void printTo(Device device){
        if(device instanceof Phone){
            System.out.println("print Triangle to Phone");
        }else if(device instanceof Watch){
            System.out.println("print Triangle to Watch");
        }
    }
}