在模板模式中,一个抽象类公开定义了执行它的方法的方式/模板。它的子类可以按需要重写方法实现,但调用将以抽象类中定义的方式进行。
创建一个抽象类,它的模板方法被设置为 final:
public abstract class Game {
abstract void initialize();
abstract void startPlay();
abstract void endPlay();
//模板
public final void play(){
//初始化游戏
initialize();
//开始游戏
startPlay();
//结束游戏
endPlay();
}
}
扩展了上述类的实体类:
public class Cricket extends Game {
@Override
void endPlay() {
System.out.println("Cricket Game Finished!");
}
@Override
void initialize() {
System.out.println("Cricket Game Initialized! Start playing.");
}
@Override
void startPlay() {
System.out.println("Cricket Game Started. Enjoy the game!");
}
}
public class Football extends Game {
@Override
void endPlay() {
System.out.println("Football Game Finished!");
}
@Override
void initialize() {
System.out.println("Football Game Initialized! Start playing.");
}
@Override
void startPlay() {
System.out.println("Football Game Started. Enjoy the game!");
}
}
使用 Game 类的模板方法 play() 来演示游戏的定义方式。
public class Client {
public static void main(String[] args) {
Game game = new Cricket();
game.play();
System.out.println();
game = new Football();
game.play();
}
}
输出:
Cricket Game Initialized! Start playing.
Cricket Game Started. Enjoy the game!
Cricket Game Finished!
Football Game Initialized! Start playing.
Football Game Started. Enjoy the game!
Football Game Finished!