Template Method Pattern Example

/**
 * 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 : */
    final void playOneGame(int playersCount) {
        this.playersCount = playersCount;
        initializeGame();
        int j = 0;
        while (!endOfGame()) {
            makePlay(j);
            j = (j + 1) % playersCount;
        }
        printWinner();
    }
}
 
//Now we can extend this class in order to implement actual games:
 
class Monopoly extends Game {
 
    /* Implementation of necessary concrete methods */
 
    void initializeGame() {
        // Initialize money
    }
 
    void makePlay(int player) {
        // Process one turn of player
    }
 
    boolean endOfGame() {
        // Return true if game is over according to Monopoly rules
    }
 
    void printWinner() {
        // Display who won
    }
 
    /* Specific declarations for the Monopoly game. */
 
    // ...
 
}
 
class Chess extends Game {
 
    /* Implementation of necessary concrete methods */
 
    void initializeGame() {
        // 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
    }
 
    void printWinner() {
        // Display the winning player
    }
 
    /* Specific declarations for the chess game. */
 
    // ...
 
}
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