设计模式的学习之路，工厂模式加桥模式

   设计模式暂时只看到适配器模式，逛“设计模式”版的时候看到了一道题目，拿来练练手。废话不多说，题目如下：

 "假设是原始社会,有石头,2块石头互磨可以变成石刀,石刀可以去砍木头,木头被砍成木材,木材可以组成椅子,请你用oo的  
  思想把这些事物和他们之间的关系表达出来,但是要考虑到以后可能我会增加以下几点: 

  "1.有可能我还想让石刀去砍椅子,把椅子砍成木材,
  2.可能我还想让石头增加关系,例如互相砸,互相摔,而不只是磨,也可以变成石刀,
  3也许我又要多添一百种不同的事物,再多添120种不同的关系..." 

  也就是说我的要求可能是不断变化的,所以你要怎么样设计这个oo的模型,可以让我在实行1,2,3条的时候只做最小的修改.... 

   先上uml图

 

代码，时间不多回家加注释。

//主要接口是材料，工具也可以当做材料 //工具接口继承材料 //所有的操作都继承自option //不同材料的属性不同，属性改变则材料被改变了 //工具的特有属性，改变能力 //操作的特有属性，改变能力 //执行操作的时候必须要有材料和操作对象，工具可以没有。 //执行操作的最终结果是改变材料的属性，当然也可能操作后属性不变。 //改变属性的程度由材料的属性，工具的改变能力和操作的改变能力决定。 #include "stdio.h" #include <string.h> #include <iostream> //定义不同材料的type值，用于工厂创建不同对象 #define STONE 0 #define WOOD 1 #define LUMBER 2 #define CHAIR 3 #define STONEKNIFE 4 //定义不同操作的type，用于工厂创建不同操作 #define CUT 0 #define COMPOSE 1 #define MILL 2 using namespace std; //材料类，可以看成一个接口 class Material { public: virtual ~Material(){}; int GetProperty() { return mProperty; } protected: Material(){}; int mProperty; }; class Tool:public Material { public: virtual ~Tool(){}; int GetChangeAbility(){return mChangeAbility;} protected: Tool(){}; int mChangeAbility; private: }; class Option { public: virtual ~Option(){}; int GetChange(Tool* aTool,Material* aMaterial){ //该函数内容用来决定经过操作后，属性改变的程度，这部分代码没有借鉴性，为了测试用的。 if (aTool->GetChangeAbility() == 1)//ʯµ¶ { if (aMaterial->GetProperty() == 1)//ľͷ { if (mChageAbility ==0) { return 1; } } } if (aTool->GetChangeAbility() == 0)//ʯͷ { if (aMaterial->GetProperty() == 0)//ʯͷ { if (mChageAbility ==2) { return 4; } } } if ((aTool == NULL)&&(aMaterial->GetProperty()==2)&&(mChageAbility == 1)) { return 1; } return 0; } int DoOption(Tool* aTool,Material* aMaterial){ int numChange = GetChange(aTool,aMaterial); return aMaterial->GetProperty()+numChange; } int getChageAbility(){return mChageAbility;} int mChageAbility; protected: Option(){}; private: }; class stone:public Tool { public: stone(){ cout<<"stone construct"<<endl; mProperty = 0; mChangeAbility = 0; } ~stone(){ cout<<"stone destroy"<<endl; } }; class Wood:public Material { public: Wood(){ cout<<"wood construct"<<endl; mProperty = 1; } ~Wood(){ cout<<"Wood destroy"<<endl; } }; class Lumber:public Material { public: Lumber(){ cout<<"Lumber construct"<<endl; mProperty = 1; } ~Lumber(){ cout<<"Lumber destroy"<<endl; } }; class Chair:public Material { public: Chair(){ cout<<"Chair construct"<<endl; mProperty = 1; } ~Chair(){ cout<<"Chair destroy"<<endl; } }; class StoneKnife:public Tool { public: StoneKnife(){ cout<<"StoneKnife construct"<<endl; mChangeAbility = 1; } ~StoneKnife(){ cout<<"StoneKnife destroy"<<endl; } }; class Cut:public Option { public: Cut(){ cout<<"Cut construct"<<endl; mChageAbility = 0; } ~Cut(){ cout<<"Cut destroy"<<endl; } }; class Compose:public Option { public: Compose(){ cout<<"Compose construct"<<endl; mChageAbility = 1; } ~Compose(){ cout<<"Compose destroy"<<endl; } }; class Mill:public Option { public: Mill(){ cout<<"Mill construct"<<endl; mChageAbility = 2; } ~Mill(){ cout<<"Mill destroy"<<endl; } }; //工厂模式，用于创建材料和操作 class Factroy { public: Factroy(){cout<<"Factroy construct"<<endl;} ~Factroy(){cout<<"Factroy destory"<<endl;} Material* CreateMaterial(int aMaterialType) { Material* retMaterial=NULL; switch (aMaterialType) { case STONE: retMaterial = new stone(); break; case WOOD: retMaterial = new Wood(); break; case LUMBER: retMaterial = new Lumber(); break; case CHAIR: retMaterial = new Chair(); break; case STONEKNIFE: retMaterial = new StoneKnife(); } return retMaterial; } Option* CreateOption(int aOptionType) { Option* retOption = NULL; switch(aOptionType) { case CUT: retOption = new Cut(); break; case COMPOSE: retOption = new Compose(); break; case MILL: retOption = new Mill(); break; } return retOption; } void DistoryMaterial(Material* aMaterial) { delete aMaterial; aMaterial = NULL; } void DistoryOption(Option* aOption) { delete aOption; aOption = NULL; } }; //用户端，以上代码用户可见的仅为材料，工具和操作三个接口,从而保证了封装性。 //用户只需要把材料，工具和操作交给模块，就可以得到输出。 void main() { Factroy fac; Material* ret; Material* stone1 = fac.CreateMaterial(STONE); Tool* stone2 = (Tool*)(fac.CreateMaterial(STONE)); Option* mill = fac.CreateOption(MILL); int MaterialType = mill->DoOption(stone2,stone1); fac.DistoryMaterial(stone1); ret = fac.CreateMaterial(MaterialType); fac.DistoryMaterial((Material*)stone2); fac.DistoryMaterial(ret); fac.DistoryOption(mill); }