행위패턴 : Template Method 패턴

분류 : 행위패턴(Behavioral Patterns)

정의 :

메소드에서 알고리즘의 뼈대를 정의하는 패턴. C++의 Template하고는 상관 없음.

용도 :

코드에서의 중복을 피하기 위해서임. 공통적인 작업흐름은 추상클래스쪽에 한번 정의하고, 나머지 다양한 구현들은 각각의 서브클래스들에서 담당함.

소스

/**
 * An abstract class that is common to several games in
 * which players play against the others, but only one is
 * playing at a given time.
 */
 
abstract class Game {
 
    protected int playersCount;
    abstract void initializeGame();
    abstract void makePlay(int player);
    abstract boolean endOfGame();
    abstract void printWinner();
 
    /** A template method : */
    public final void playOneGame(int playersCount) {
        this.playersCount = playersCount;
        initializeGame();
        int j = 0;
        while (!endOfGame()) {
            makePlay(j);
            j = (j + 1) % playersCount;
        }
        printWinner();
    }
}


class Chess extends Game {
	 
    /** Implementation of necessary concrete methods */
    void initializeGame() {
        // Initialize players
        // Put the pieces on the board
    }
    void makePlay(int player) {
        // Process a turn for the player
    }
    boolean endOfGame() {
        // Return true if in Checkmate or 
        // Stalemate has been reached
    	return true;
    }
    void printWinner() {
        // Display the winning player
    }
    /** Specific declarations for the chess game. */
 
    // ...
}


//Now we can extend this class in order 
//to implement actual games:

class Monopoly extends Game {

  /** Implementation of necessary concrete methods */
  void initializeGame() {
      // Initialize players
      // Initialize money
  }
  void makePlay(int player) {
      // Process one turn of player
  }
  boolean endOfGame() {
      // Return true if game is over 
      // according to Monopoly rules
	  return true;
  }
  void printWinner() {
      // Display who won
  }
  /** Specific declarations for the Monopoly game. */

  // ...
}

참고자료

http://en.wikipedia.org/wiki/Template_method_pattern