[Java] [Design Pattern] An example for Template Method Pattern

Here has four steps to demonstrate template method pattern:

1. Create an abstract class with a template method being final.

package com.example.pattern.template;

public abstract class Game {

    abstract void initializeGame();
    abstract void playGame();
    abstract void endGame();

    /**
     * template method
     */
    public final void play() {
        initializeGame();
        playGame();
        endGame();
    }

}

2. Create concrete classes extending the above class.

package com.example.pattern.template;

import lombok.extern.slf4j.Slf4j;

@Slf4j
public class FishingStrike extends Game {

    @Override
    void initializeGame() {
        log.debug("Fishing Strike initialized!");
    }

    @Override
    void playGame() {
        log.debug("Fishing Strike started! Enjoy the game!");
    }

    @Override
    void endGame() {
        log.debug("Fishing Strike finished! See you!");
    }
}

package com.example.pattern.template;

import lombok.extern.slf4j.Slf4j;

@Slf4j
public class MiniGolfKing extends Game {

    @Override
    void initializeGame() {
        log.debug("Mini Golf King initialized!");
    }

    @Override
    void playGame() {
        log.debug("Mini Golf King started! Enjoy the game!");
    }

    @Override
    void endGame() {
        log.debug("Mini Golf King finished! See you!");
    }
}

3. Create a demo class to use the Game's template method play() to demonstrate a defined way of playing game.

package com.example.pattern.template;

import org.springframework.stereotype.Component;

@Component
public class TemplatePatternDemo {

    /**
     * play fishing strike game
     */
    public void playFishingStrike() {
        Game fishingStrike = new FishingStrike();
        fishingStrike.play();
    }

    /**
     * play mini golf king game
     */
    public void playMiniGolfKing() {
        Game miniGolfKing = new MiniGolfKing();
        miniGolfKing.play();
    }

}

4. Autowired TemplatePatternDemo to play execute methods and verify output

package com.example.test;

import com.example.pattern.template.TemplatePatternDemo;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;

@SpringBootApplication
@ComponentScan(basePackages = "com.example")
public class TestApplication {

    public static void main(String[] args) {
        SpringApplication.run(TestApplication.class, args);
    }

    @Bean
    CommandLineRunner run(TemplatePatternDemo demo) {
        return args -> {
            demo.playFishingStrike();
            demo.playMiniGolfKing();
        };
    }
}

[main] c.e.pattern.template.FishingStrike       : Fishing Strike initialized!
[main] c.e.pattern.template.FishingStrike       : Fishing Strike started! Enjoy the game!
[main] c.e.pattern.template.FishingStrike       : Fishing Strike finished! See you!
[main] c.example.pattern.template.MiniGolfKing  : Mini Golf King initialized!
[main] c.example.pattern.template.MiniGolfKing  : Mini Golf King started! Enjoy the game!
[main] c.example.pattern.template.MiniGolfKing  : Mini Golf King finished! See you!