12. 컴파운드 패턴

12. 컴파운드 패턴

1. 패턴 섞어 쓰기

1.1 컴파운드 패턴

컴파운드 패턴이란 반복적으로 생길 수 있는 문제를 해결하기 위한 용도로 두 개 이상의 패턴을 결합하여 사용하는 것을 뜻함

1.2 오리와의 재회

1.2.1 오리에 적용될 패턴

1. 처음에 수많은 Quackable 들이 존재
2. 갑자가 거위가 나타나서는 자기도 Quackable이 되고 싶다고함 (어댑터 패턴)
3. 꽥학자들이 등장해서 꽥소리 회수를 세고 싶다고함 (데코레이터 패턴)
4. 꽥학자들이 QuackCounter로 장식되지 않은 Quackable 객체가 있을것을 걱정 (추상팩토리 패턴)
5. 모든 오리와 거위, Quackable 객체들을 관리하는 게 힘들어지기 시작 - 오리떼로 관리 (컴포지트 패턴)
6. 꽥학자들은 Quackable에서 꽥소리를 냈을 때 그런 일이 있었다는 것을 연락받고 싶어함 (옵저버 패턴)

1.2.2 오리가 본 조감도

1.2.3 오리와의 재회

수많은 Quackable 들이 존재

거위가 나타나서는 자기도 Quackable이 되고 싶다고함

{code:java}
//==============================================
// 1. 우선 Quackable 인터페이스를 만듭니다.
//==============================================
public insterface Quackable{
public void quack();
}
{code}{code:java}
//==============================================
// 2. Quackable 을 구현해서 오리 클래스를 만듭니다.
//==============================================
public class MallardDuck implements Quackable{
public void quack(){
System.out.println("Quack");
}
}

public class RedheadDuck implements Quackable{
public void quack(){
System.out.println("Quack");
}
}

public class DuckCall implements Quackable{
public void quack(){
System.out.println("Quack");
}
}

public class RubberDuck implements Quackable{
public void quack(){
System.out.println("Quack");
}
}

{code:java}
//==============================================
// 3. 시뮬레이터 생성
//==============================================
public class DuckSimulator{
   public static void main(String[] args){
      DuckSimulator simulator = new DuckSimulator();
      simulator.simulate();
   }

   void simulate(){
      Quackable mallardDuck = new MallardDuck();
      Quackable redheadDuck= new RedheadDuck();
      Quackable duckCall = new DuckCall();
      Quackable rubberDuck = new RubberDuck();

      System.out.println("\nDuck Simulator");

      simulate(mallardDuck);
      simulate(redheadDuck);
      simulate(duckCall);
      simulate(rubberDuck);
   }

   void simulate(Quackable duck){
      duck.quack();
   }
}

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//==============================================
// 4. 오리 있는곳에 거위도 있다.
//==============================================
public class Goose{
   public void honk();{
      System.out.println("Honk");
   }
}


//==============================================
// 5. 거위용 어댑터 필요
//==============================================
public class GooseAdapter implements Quackable{
   Goose goose;

   public GooseAdapter(Goose goose){
      this.goose = goose;
   }

   public void quack(){
      goose.honk();
   }
}


//==============================================
// 5. 거위를 추가한 시뮬레이터
//==============================================
public class DuckSimulator{
   public static void main(String[] args){
      DuckSimulator simulator = new DuckSimulator();
      simulator.simulate();
   }

   void simulate(){
      Quackable mallardDuck = new MallardDuck();
      Quackable redheadDuck= new RedheadDuck();
      Quackable duckCall = new DuckCall();
      Quackable rubberDuck = new RubberDuck();
      Quackable gooseDuck = new GooseAdapter(new Goose());

      System.out.println("\nDuck Simulator : With Goose Adapter");

      simulate(mallardDuck);
      simulate(redheadDuck);
      simulate(duckCall);
      simulate(rubberDuck);
      simulate(gooseDuck);
   }

   void simulate(Quackable duck){
      duck.quack();
   }
}

|

꽥소리 회수를 세고 싶다고함	QuackCounter로 장식되지 않은 Quackable 객체가 있을것을 걱정
{code:java} //============================================== // 6. 꽥소리를 낸 회수를 세 주는 기능 선물 //============================================== public class QuackCounter implements Quackable{ Quackable duck; static int numberOfQuacks;

public void QuackCounter(Quackable duck){
duck.quack();
numberOfQuacks++;
}

public static int getQuack(){
return numberOfQuacks;
}
}

{code:java}
//==============================================
// 7. 모든 오리들을 데코레이터로 감싸줍니다.
//==============================================
public class DuckSimulator{
   public static void main(String[] args){
      DuckSimulator simulator = new DuckSimulator();
      simulator.simulate();
   }

   void simulate(){
      Quackable mallardDuck = new QuackCounter(new MallardDuck());
      Quackable redheadDuck= new QuackCounter(new RedheadDuck());
      Quackable duckCall = new QuackCounter(new DuckCall());
      Quackable rubberDuck = new QuackCounter(new RubberDuck());
      Quackable gooseDuck = new GooseAdapter(new Goose());

      System.out.println("\nDuck Simulator : With Decorator");

      simulate(mallardDuck);
      simulate(redheadDuck);
      simulate(duckCall);
      simulate(rubberDuck);
      simulate(gooseDuck);

      System.out.println("The ducks quacked "+QuackCounter.getQuacks()
                     + " times");
   }

   void simulate(Quackable duck){
      duck.quack();
   }
}

|


//==============================================
// 8. 오리를 생산하기 위한 팩토리가 필요
//==============================================
public abstract class AbstractDuckFactory{

   public abstract Quackable createMallardDuck();
   public abstract Quackable createRedheadDuck();
   public abstract Quackable createDuckCall();
   public abstract Quackable createRubberDuck();
}


//==============================================
// 9. 데코레이터가 없는 Factory 와 진짜로 사용할 CountingDuckFactory
//==============================================
public class DuckFactory extends AbstractDuckFactory{

   public Quackable createMallardDuck(){
      return new MallardDuck();
   }

   public Quackable createRedheadDuck(){
      return new ReadheadDuck();
   }

   public Quackable createDuckCall(){
      return new DuckCall();
   }

   public Quackable createRubberDuck(){
      return new RubberDuck();
   }
}

public class CountingDuckFactory extends AbstractDuckFactory{

   public Quackable createMallardDuck(){
      return QuackCounter(new MallardDuck());
   }

   public Quackable createRedheadDuck(){
      return QuackCounter(new ReadheadDuck());
   }

   public Quackable createDuckCall(){
      return QuackCounter(new DuckCall());
   }

   public Quackable createRubberDuck(){
      return QuackCounter(new RubberDuck());
   }
}


//==============================================
// 10. 팩토리를 사용하도록 시뮬레이터 수정
//==============================================
public class DuckSimulator{
   public static void main(String[] args){
      DuckSimulator simulator = new DuckSimulator();
      AbstractDuckFactory duckFactory = new CountingDuckFactory();

      simulator.simulate(duckFactory);
   }

   void simulate(AbstractDuckFactory duckFactory){
      Quackable mallardDuck = duckFactory.createMallardDuck();
      Quackable redheadDuck= duckFactory.createReadheadDuck();
      Quackable duckCall = duckFactory.createDuckCall();
      Quackable rubberDuck = duckFactory.createRubberDuck();
      Quackable gooseDuck = new GooseAdapter(new Goose());

      System.out.println("\nDuck Simulator : With Decorator");

      simulate(mallardDuck);
      simulate(redheadDuck);
      simulate(duckCall);
      simulate(rubberDuck);
      simulate(gooseDuck);

      System.out.println("The ducks quacked "+QuackCounter.getQuacks()
                       + " times");
   }

   void simulate(Quackable duck){
      duck.quack();
   }
}

|

오리떼로 관리	꽥소리를 냈을 때 그런 일이 있었다는 것을 연락받고 싶어함
{code:java} //============================================== // 11. 오리떼를 만들어 봅니다. //============================================== public class Flock implements Quackable{ ArrayList quackers = new ArrayList();

public void add(Quackable quacker){
quacker.add(quacker);
}

public void quack(){
Iterator iterator = quacker.iterator();
while(iterator.hasNext()){
Quackable quacker = (Quackable)iterator.next();
quacker.quack();
}
}
}

{code:java}
//==============================================
// 12. 시뮬레이터를 수정
//==============================================
public class DuckSimulator{
   public static void main(String[] args){
      DuckSimulator simulator = new DuckSimulator();
      AbstractDuckFactory duckFactory = new CountingDuckFactory();

      simulator.simulate(duckFactory);
   }

   void simulate(AbstractDuckFactory duckFactory){

      Quackable redheadDuck= duckFactory.createReadheadDuck();
      Quackable duckCall = duckFactory.createDuckCall();
      Quackable rubberDuck = duckFactory.createRubberDuck();
      Quackable gooseDuck = new GooseAdapter(new Goose());

      System.out.println("\nDuck Simulator : With Composite-Flocks");

      Flock flockOfDucks = new Flock();

      flockOfDucks.add(redheadDuck);
      flockOfDucks.add(duckCall);
      flockOfDucks.add(rubberDuck);
      flockOfDucks.add(gooseDuck);

      Flock flockOfMallards = new Flock();

      Quackable mallardOne = duckFactory.createMallardDuck();
      Quackable mallardTwo = duckFactory.createMallardDuck();
      Quackable mallardThree = duckFactory.createMallardDuck();
      Quackable mallardFour = duckFactory.createMallardDuck();

      flockOfMallards.add(mallardOne);
      flockOfMallards.add(mallardTwo);
      flockOfMallards.add(mallardThree);
      flockOfMallards.add(mallardFour);

      flockOfDucks.add(flockOfMallards);

      System.out.println("\nDuck Simulator : Whole Flock Simulator");
      simulate(flockOfDucks);

      System.out.println("\nDuck Simulator : Mallard Flock Simulator");
      simulate(flockOfMallards);

      System.out.println("The ducks quacked "+QuackCounter.getQuacks()
                       + " times");
   }

   void simulate(Quackable duck){
      duck.quack();
   }
}

|


//==============================================
// 13. Observable 인터페이스 필요
//==============================================
public interface QuackObservable{
   public void registerObserver(Observer observer);
   public void notifyObservers();
}

public interface Quackable extends QuackObservable{
   public void quack();
}


//==============================================
// 14. 메소드 구현
//==============================================
public class Observable implements QuackObservable{
   ArrayList observers = new ArrayList();
   QuackObservable duck;

   public Observable(QuackObservable duck){
      this.duck = duck;
   }

   public void reigisterObserver(Observer observer){
      observers.add(observer);
   }

   public void notifyObservers(){
      Iterator iterator = observers.iterator();
      while(iterator.hasNext()){
         Observer observer = (Observer)iterator.next();
         observer.update(duck);
      }
   }
}


//==============================================
// 15. Observer 보조객체와 Quackable 클래스를 결합
//==============================================
public class MallardDuck implements Quackable{
   Observable observable;

   public MallardDuck(){
      observable = new Observable(this);
   }

   public void quack(){
      System.out.println("Quack");
      notifyObservers();
   }

   public void registerObserver(Observer observer){
      observable.registerObserver(observer)
   }

   public void notifyObservers(){
      observable.notifyObservers();
   }
}


//==============================================
// 16. 옵저버 패턴의 옵저버 쪽 완성
//==============================================
public interface Observer{
   public void update(QuackObservable duck);
}

public class Quackologist implements Observer{

   System.out.println("Quackologist:+duck+" just quacked.");
}


//==============================================
// 17. 시뮬레이터 수정
//==============================================
public class DuckSimulator{
   public static void main(String[] args){
      DuckSimulator simulator = new DuckSimulator();
      AbstractDuckFactory duckFactory = new CountingDuckFactory();

      simulator.simulate(duckFactory);
   }

   void simulate(AbstractDuckFactory duckFactory){

      Quackable redheadDuck= duckFactory.createReadheadDuck();
      Quackable duckCall = duckFactory.createDuckCall();
      Quackable rubberDuck = duckFactory.createRubberDuck();
      Quackable gooseDuck = new GooseAdapter(new Goose());

      System.out.println("\nDuck Simulator : With Composite-Flocks");

      Flock flockOfDucks = new Flock();

      flockOfDucks.add(redheadDuck);
      flockOfDucks.add(duckCall);
      flockOfDucks.add(rubberDuck);
      flockOfDucks.add(gooseDuck);

      System.out.println("\nDuck Simulator : With Observer");
      Quackologist quackologist = new Quackologist();
      flockOfDucks.registerObserver(quackologist);

      System.out.println("\nDuck Simulator : Whole Flock Simulator");
      simulate(flockOfDucks);

      System.out.println("The ducks quacked "+QuackCounter.getQuacks()
                       + " times");
   }

   void simulate(Quackable duck){
      duck.quack();
   }
}

|

2. 모델-뷰-컨트롤러와의 만남(MVC)

2.1 모델-뷰-컨트롤러와의 만남

모델에서는 옵저버 패턴을 사용하여 상태가 바뀔 때마다 뷰와 컨트롤러한테 연락을 함
뷰와 컨트롤러에서는 스트래티지 패턴을 사용 : 컨트롤러는 뷰의 행동에 해당하며, 다른 행동을 원하면 다른 컨틀롤러로 교체하면 된다
뷰 안에서는 내부적으로 컴포진트 패턴을 사용

2.2 옵저버 패턴

2.3 스트래티지 패턴

2.4 컴포지트 패턴

3. MVC 와 웹환경

3.1 MVC 와 웹환경

1. 사용자가 HTTP요청을 하면 서블릿에서 그 요청을 수신
2. 서블릿이 컨트롤 역할을 합니다.
3. 컨트롤러에서는 컨트롤을 뷰한테 넘깁니다.
4. 뷰에서 HTTP를 통해서 브라우저한테 페이지를 전달합니다.

3.2 모델2

모델2는 MVC를 웹에 맞게 적용	모델
	{code:java} //============================================== // 1. BeatModel Interface //============================================== public interface BeatModelInterface{ void initialize();

void on();

void off();

void setBPM(int bpm);

int getBPM();

void registerObserver(BeatObserver o);

void removeObserver(BeatObserver o);

void registerObserver(BPMObserver o);

void removeObserver(BPMObserver o);
}

{code:java}
//==============================================
// 2. BeatModel 구상 클래스
//==============================================
public class BeatModel implements BeatModelInterface{
   Sequencer sequencer;
   ArrayList beatObservers = new ArrayList();
   ArrayList bpmObservers = new ArrayList();
   int bpm = 90;

   public void initialize(){
      setUpMidi();
      buildTrackAndStart();
   }

   public void on(){
      sequencer.start();
      setBPM(90);
   }

   public void off(){
      setBPM(0);
      sequencer.stop();
   }

   public void setBPM(int bpm){
      this.bpm = bpm;
      sequencer.setTempoInBPM(getBPM());
      notifyBPMObservers();
   }

   public int getBPM(){
      return bpm;
   }

   void beatEvent(){
      notifyBeatObservers();
   }

   // 옵저버 등록및 해제용 코드

   // 음악을 만들어내기 위한 미디코드
}

|

컨트롤러 서블릿	뷰
{code:java} //============================================== // 2. 컨트롤러 서블릿 //============================================== public class DJView extends HttpServlet{ public void init() throws ServletException{ BeatModel beatModel = new BeatModel(); beatModel.initialize(); getServletContext().setAttribute("beatModel",beatModel); }

public void doGet(HttpServletRequset request,
HttpServletResponse response)
throws IOException, ServletException
{
BeatModel beatModel =
(BeatModel)getServletContext.getAttribute("beatModel");

String bpm = request.getParameter("bpm");
if(bpm==null){
bpm = beatModel.getBPM() + "";
}

String set = request.getParameter("set");
if(set==null){
int bpmNumber = 90;
bpmNumber = Integer.parseInt(bpm);
beatModel.setBPM(bpmNumber);
}

String decrease = request.getParameter("decrease");
if(decrease==null){
beatModel.setBPM(beatModel.getBPM()-1);
}

String increase = request.getParameter("increase");
if(increase==null){
beatModel.setBPM(beatModel.getBPM()+1);
}

String on = request.getParameter("on");
if(on==null){
beatModel.start();
}

String off = request.getParameter("off");
if(off==null){
beatModel.stop();
}

request.setAttribute("beatModel",beatModel);

RequestDispatcher dispatcher =
request.getRequestDispatcher("/jsp/DJview.jsp");
dispatcher.forward(request.response);
}
}

| {code:java}
//==============================================
// 3. 뷰(JSP)
//==============================================
<jsp:useBean id="beatModel" scope="request" class="headfirst.combined.djview.BeatModel"/>

<html>
<head>
<title>DJ View</title>
</head>
<body>
<h1>DJ View</h1>
Beats per minutes = <jsp:getProperty name="beatModel" property="BPM"/>
<br/>
<hr>
<br/>
<form method="post" action="/djview/servlet/DJView">
BPM: <input type=text name="bpm" value="<jsp:getProperty name="beatModel" property="BPM" />
 
<input type="submit" name="set" value="set"><br/>
<input type="submit" name="decrease" value="<<"><br/>
<input type="submit" name="increase" value=">>"><br/>
<input type="submit" name="on" value="on"><br/>
<input type="submit" name="off" value="off"><br/>
</form>
</html>

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문서에 대하여

최초작성자 : WEBSTUDY:최성식
최초작성일 : 2008년 05월 23일
이 문서는 HeadFirst Design Patterns을 정리한 내용 입니다.
이 문서는 오라클클럽 자바 웹개발자 스터디 모임에서 작성하였습니다.
이 문서를 다른 블로그나 홈페이지에 게재할 경우에는 출처를 꼭 밝혀 주시면 고맙겠습니다.