介绍
模板方法模式( ),也称为模板模式,是一种行为模式。 它定义了一个抽象公共类,其中包含基本算法骨架,并将一些步骤推迟到子类中。 模板方法允许子类在不改变算法结构的情况下重新定义算法的一些具体步骤。 不同的子类以不同的方式实现这些抽象方法,因此剩余逻辑的实现也不同。 这样,基于公共模板,就可以实现不同的功能。
模板模式适合一些复杂的操作进行步骤划分,提取抽象父类要实现的公共部分,在父类中定义不同部分的抽象实现,由子类完成具体的实现过程。 对于多个具有公共方法、相同逻辑的子类,可以认为是模板方法。
部分具有相同功能的父类提供统一模板,子类大量复用,从而节省代码,复用逻辑。 封装不变部分,扩展可变部分,行为由父类控制,子类可以灵活实现,易于维护和扩展。 实现步骤创建一个抽象模板类,定义基本流程,并定义一些基本方法供子类实现。 创建多个子类继承抽象模板并覆盖父类的相关动作和方法。 统一建模语言
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Java代码抽象模板类
// GameTemplate.java 定义抽象模板类,有抽象方法和具体方法
public abstract class GameTemplate {
// 抽象方法待子类来实现
abstract void init();
abstract void start();
abstract void end();
// 可复用的算法流程
public void play() {
System.out.println(this.getClass().getSimpleName() + "::play()");
// 初始化游戏
init();
// 开始游戏
start();
// 结束游戏
end();
}
}
具体业务类,继承抽象模板
// Basketball.java 定义子类覆写父类抽象方法
public class Basketball extends GameTemplate {
@Override
void init() {
System.out.println("Basketball::init() [Basketball Game Initialized! Start playing.]");
}
@Override
void start() {
System.out.println("Basketball::start() [Basketball Game Started. Enjoy the game!]");
}
@Override
void end() {
System.out.println("Basketball::end() [Basketball Game Finished!]");
}
}
// Football.java 定义子类覆写父类抽象方法
public class Football extends GameTemplate {
@Override
void init() {
System.out.println("Football::init() [Football Game Initialized! Start playing.]");
}
@Override
void start() {
System.out.println("Football::start() [Football Game Started. Enjoy the game!]");
}
@Override
void end() {
System.out.println("Football::end() [Football Game Finished!]");
}
}
// Tennis.java 定义子类覆写父类抽象方法
public class Tennis extends GameTemplate {
@Override
void init() {
System.out.println("Tennis::init() [Tennis Game Initialized! Start playing.]");
}
@Override
void start() {
System.out.println("Tennis::start() [Tennis Game Started. Enjoy the game!]");
}
@Override
void end() {
System.out.println("Tennis::end() [Tennis Game Finished!]");
}
// 在调用父类play之前,如果要执行自己的行为,也可以覆盖父类方法
// 先执行自己的,再调用父类的方法
@Override
public void play() {
System.out.println("Tennis::play() [Tennis Game play!]");
super.play();
}
}
测试通话
GameTemplate football = new Football();
football.play();
System.out.println("===");
GameTemplate basketball = new Basketball();
basketball.play();
System.out.println("===");
GameTemplate tennis = new Tennis();
tennis.play();
C语言代码头文件
// 函数.h
#include
#include
#include
#include
#include
typedef struct GameTemplate GameTemplate;
typedef struct Football Football;
typedef struct Basketball Basketball;
typedef struct Tennis Tennis;
// 定义抽象模板,包括各种动作和公共流程
typedef struct GameTemplate
{
char name[50];
void (*init)(GameTemplate *game);
void (*start)(GameTemplate *game);
void (*end)(GameTemplate *game);
void (*play)(GameTemplate *game);
} GameTemplate;
void template_play(GameTemplate *game);
GameTemplate *game_template_constructor(char *name);
// 定义子类覆写父类抽象方法
typedef struct Football
{
char name[50];
void (*init)(Football *game);
void (*start)(Football *game);
void (*end)(Football *game);
void (*play)(Football *game);
} Football;
Football *football_constructor(char *name);
// 定义子类覆写父类抽象方法
typedef struct Basketball
{
char name[50];
void (*init)(Basketball *game);
void (*start)(Basketball *game);
void (*end)(Basketball *game);
void (*play)(Basketball *game);
} Basketball;
Basketball *basketball_constructor(char *name);
// 定义子类覆写父类抽象方法
typedef struct Tennis
{
char name[50];
void (*init)(Tennis *game);
void (*start)(Tennis *game);
void (*end)(Tennis *game);
void (*play)(Tennis *game);
} Tennis;
Tennis *tennis_constructor(char *name);
抽象模板类
// game_template.c 定义抽象模板类,有抽象方法和具体方法
#include "func.h"
// 定义抽象模板类的公共部分,这里用struct替代
// 抽象方法待子类来实现
void template_init(GameTemplate *game) {}
void template_start(GameTemplate *game)
{
printf("\r\n GameTemplate::start() [GameTemplate Initialized! Start playing.]");
}
void template_end(GameTemplate *game) {}
// 可复用的算法流程
void template_play(GameTemplate *game)
{
printf("\r\n GameTemplate::play() [name=%s]", game->name);
// 初始化游戏
game->init(game);
// 开始游戏
game->start(game);
// 结束游戏
game->end(game);
}
GameTemplate *game_template_constructor(char *name)
{
// printf("\r\n game_template_constructor() [构建GameTemplate]");
GameTemplate *game = (GameTemplate *)malloc(sizeof(GameTemplate));
strcpy(game->name, name);
game->init = &template_init;
game->start = &template_start;
game->end = &template_end;
game->play = &template_play;
return game;
}
具体业务类,继承抽象模板
// basketball.c 定义子类覆写父类抽象方法
#include "func.h"
// 定义子类覆写父类抽象方法
void basketball_init(Basketball *game)
{
printf("\r\n Basketball::init() [Basketball Game Initialized! Start playing.]");
}
void basketball_start(Basketball *game)
{
printf("\r\n Basketball::start() [Basketball Game Started. Enjoy the game!]");
}
void basketball_end(Basketball *game)
{
printf("\r\n Basketball::end() [Basketball Game Finished!]");
}
Basketball *basketball_constructor(char *name)
{
printf("\r\n basketball_constructor() [构建Basketball]");
GameTemplate *template = game_template_constructor(name);
Basketball *game = (Basketball *)template;
game->init = &basketball_init;
// 如果不覆盖则使用基类的函数
// game->start = &basketball_start;
game->end = &basketball_end;
return game;
}
// football.c 定义子类覆写父类抽象方法
#include "func.h"
// 定义子类覆写父类抽象方法
void football_init(Football *game)
{
printf("\r\n Football::init() [Football Game Initialized! Start playing.]");
}
void football_start(Football *game)
{
printf("\r\n Football::start() [Football Game Started. Enjoy the game!]");
}
void football_end(Football *game)
{
printf("\r\n Football::end() [Football Game Finished!]");
}
Football *football_constructor(char *name)
{
printf("\r\n football_constructor() [构建Football]");
GameTemplate *template = game_template_constructor(name);
Football *game = (Football *)template;
game->init = &football_init;
game->start = &football_start;
game->end = &football_end;
return game;
}
// tennis.c 定义子类覆写父类抽象方法
#include "func.h"
// 定义子类覆写父类抽象方法
void tennis_init(Tennis *game)
{
printf("\r\n Tennis::init() [Tennis Game Initialized! Start playing.]");
}
void tennis_start(Tennis *game)
{
printf("\r\n Tennis::start() [Tennis Game Started. Enjoy the game!]");
}
void tennis_end(Tennis *game)
{
printf("\r\n Tennis::end() [Tennis Game Finished!]");
}
// 在调用父类play之前,如果要执行自己的行为,也可以覆盖父类方法
void tennis_play(Tennis *game)
{
// 先执行自己的内容,再调用基类的函数
printf("\r\n Tennis::play() [Tennis Game Play!]");
template_play((GameTemplate *)game);
}
Tennis *tennis_constructor(char *name)
{
printf("\r\n tennis_constructor() [构建Tennis]");
GameTemplate *template = game_template_constructor(name);
Tennis *game = (Tennis *)template;
game->init = &tennis_init;
game->start = &tennis_start;
game->end = &tennis_end;
game->play = &tennis_play;
return game;
}
测试通话
#include "../src/func.h"
int main(void)
{
printf("test start:\r\n");
Football *football = football_constructor("football");
football->play(football);
printf("\r\n ===");
Basketball *basketball = basketball_constructor("basketball");
basketball->play(basketball);
printf("\r\n ===");
Tennis *tennis = tennis_constructor("basketball");
tennis->play(tennis);
}
更多语言版本
不同语言设计模式的源码: