《设计模式02》-工厂方法

1、第二部分 创建型设计模式v工厂方法模式(Factory Method Pattern)v简单工厂模式(Simple Factory Pattern)v单件模式(Singleton Pattern)v构造器模式(Builder Pattern)v原型模式(Prototype Pattern)v抽象工厂模式(Abstract Factory Pattern)工厂方法模式CreateAndUse()class Clientpublic:void CreateAndUse() int sum = 0;Dog * dog = new Dog;sum+= dog-Sale();delete dog;Cat

2、 * cat = new Cat;sum+= cat-Sale();delete cat;Fish * fish = new Fish;sum+= fish-Sale();delete fish;coutsumSale(); delete ani ; IAnimal * ani = new Cat;sum+= cat-Sale();delete ani ; IAnimal * ani = new Fish;sum+= ani Sale();delete ani ;coutsumSale();delete ani;IAnimal * ani = CreateCat();sum+= ani-Sal

3、e();delete ani;IAnimal * ani = CreateFish();sum+= ani-Sale();delete ani;cout“Total Sale:”Sale();delete ani;IAnimal * ani = fac. CreateCat();sum+= ani-Sale();delete ani;IAnimal * ani = fac. CreateFish();sum+= ani-Sale();delete ani;cout“Total Sale:”Sale();delete ani;IAnimal * ani = fac. CreateAnimal(C

4、);sum+= ani-Sale();delete ani;IAnimal * ani = fac. CreateAnimal(F);sum+= ani-Sale();delete ani;cout“Total Sale:”Crete课程(1); 课程 * c2 = fac-Crete课程(2); .工厂方法模式例-多工厂课 程英 语软 件 工 程学 生+Sduty()Factory+Create课程()return new 软件工程();void 学生:Study( ) Factory * fac1 = new 软件工程Factory( ); 课程 * c1 = fac1-Crete课程()

5、; Factory * fac2 = new 专业英语Factory( ); 课程 * c2 = fac-Crete课程(); .基 础 英 语专 业 英 语英 语 Factory+Create课程()软 件 工 程 Factory+Create课程()基 础 英 语 Factory+Create课程()专 业 英 语 Factory+Create课程()return new 英语();return new 基础英语();return new 专业英语();工厂方法模式结构Client-fac1: Creator-fac2: Creator-prod1: Product-prod2: Prod

6、uct+CreateAndUse()Creator+FactoryMethod(): ProductConcreteCreator1+FactoryMethod(): ProductConcreteCreator2+FactoryMethod(): ProductProductProductAProductBreturn new ProductBreturn new ProductA工厂方法模式总结v定义一个创建产品的接口（顶层工厂类），而由该接口的子类（具体工厂类），决定具体实例化哪种产品。v即将产品的实例化延迟到接口的子类（具体工厂类）中。v也称多态性工厂方法多态性工厂方法模式或虚拟构造子

7、虚拟构造子模式工厂方法模式的适用性v优点扩展产品时，完全支持开闭原则；v新增子类产品v新增产品树v用同构的产品树替换原有产品树具有对应的层次结构，Client只通过产品的抽象接口交互，不必明确知道具体的产品v不足子类数量可能较多（有时可用类模版减少子类数量）迷宫游戏例-工厂方法模式Class MazeFactoryPublic： Maze * CreateMaze( ) ; /工厂方法 virtual Maze * MakeMaze() const return new Maze; /模版方法模式 virtual Room * MakeRoom() const return new Room;

8、 virtual Wall * MakeRoom(int n) return new Room(n); virtual Door * MakeDoor( Room* r1,Room * r2) const return new Door(r1,r2); ； Maze * CreateMaze( ) Maze * aMaze = MakeMaze(); Room * r1 = MakeRoom(1); Room * r1 =.MakeRoom(2); Door * door =MakeDoor(r1,r2); aMaze-AddRoom(r1); aMaze-AddRoom(r2); r1-Se

9、tSide(North,makeWall(); r1-SetSide(East,door); r1-SetSide(South,makeWall(); r1-SetSide(West,makeWall(); r2-SetSide(North,makeWall(); r2-SetSide(East, makeWall(); r2-SetSide(South,makeWall(); r2-SetSide(West,door); return aMaze； MazeFactory的子类BombedMazeFactoryclass BombedMazeFactory:public MazeFactor

10、 Public: BombedMazeFactory(); virtual Wall * MakeWall() const return new BombedWall; virtual Room * MakeRoom(int n) const return new RoomWithABomb(n); ;MazeFactory的子类EnchantedMazeFactoryclass EnchantedMazeFactory:public MazeFactroy public: EnchantedMazeFactory(); virtual Room* MakeRoom(int n) const

11、return new EnchantedRoom(n,CastSpell(); Virtual Door * MakeDoor(Room * r1,Room * r2) const return new DoorNeedingSpell(r1,r2); protected: Spell * CastSpell() const;Factory的使用Class GamePublic: Game(MazeFactory & fac ) aMaze = fac.CreateMaze(); Private: Maze * aMaze;Factory中的CreateMaze也可以放到Game中。Class GamePublic: Game(MazeFactory & fac ) aMaze = CreateMaze(fac); Protected: Maze * CreateMaze(MazeFactory & fac ) /将例中的MakeRoom等改成 /fac.MakeRoom。略Pri