22-04-17-프록시패턴-2부-패턴적용하기

22-04-17-프록시패턴-2부-패턴적용하기

목차

01.프록시패턴 적용

01.1 코드 수정 없이 적용하기

GameServiceProxy 추가

01.2 UML그대로 적용해보기

subject

realSubject

GameServiceProxy

Client

02.다른기능을 추가하는 경우

01.프록시패턴 적용

01.1 코드 수정 없이 적용하기

GameServiceProxy 추가

public class GameServiceProxy extends GameService{
    @Override
    public void startGame(){
        long before = System.currentTimeMillis();
        super.startGame();
        System.out.println(System.currentTimeMillis()-before);
    }
}

• before

  public class Client{
    public static void main(String[] args){
  		GameService gameService = new GameService();
        gameService.startGame();
    }
  }

• after

  public class Client{
    public static void main(String[] args){
  		GameService gameService = new GameServiceProxy();
        gameService.startGame();
    }
  }

01.2 UML그대로 적용해보기

subject

• before

  public class GameService{
    public void startGame(){
        System.out.println("이 자리에 오신 여러분을 진심으로 환영합니다.");
    }
  }

• after

  public interface GameService{
  	void startGame();
  }

  • GameService 의 경우 왠만하면 이런것은 인터페이스로 구현

realSubject

public class DefaultGameService implement GameService{
    @Override
    public void startGame(){
		System.out.println("이 자리에 오신 여러분을 진심으로 환영합니다.")
    }
}

GameServiceProxy

• before

  public class GameServiceProxy extends GameService{
    @Override
    public void startGame(){
        long before = System.currentTimeMillis();
        super.startGame();
        System.out.println(System.currentTimeMillis()-before);
    }
  }

• after

  public class GameServiceProxy implement GameService{
    private GameService gameService;
    
    public GameServiceProxy(GameService gameService){
  		this.gameServie = gameService;
    }
    @Override
    public void startGame(){
        long before = System.currentTimeMillis();
        gameService.startGame();
        System.out.println(System.currentTimeMillis()-before);
    }
  }

Client

• before

  public class Client{
    public static void main(String[] args){
  		GameService gameService = new GameServiceProxy();
        gameService.startGame();
    }
  }

• after

  public class Client{
    public static void main(String[] args){
  		GameService gameService = new GameServiceProxy(new DefaultGameService());
        gameService.startGame();
    }
  }

• 이렇게 하면 게임 서비스는 그대로 일을 하고 다른 기능등을 추가 할 수 있음

02.다른기능을 추가하는 경우

public class GameServiceProxy implement GameService{
    private GameService gameService;
    
    @Override
    public void startGame(){
        long before = System.currentTimeMillis();
        if(this.gameService == null){
            this.gameService = new DefaultGameService();
        }
        gameService.startGame();
        System.out.println(System.currentTimeMillis()-before);
    }
}

• 위와 같이 해주는 경우 클라이언트를 이렇게 그냥 해도됨

public class Client{
    public static void main(String[] args){
		GameService gameService = new GameServiceProxy();
        gameService.startGame();
    }
}