設計模式(2)-工廠方法模式

2019-11-08 01:54:35

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工廠方法模式

　　工廠方法模式屬于創建型的設計模式，把簡單工廠模式中的工廠類，做了進一步的抽象為接口或抽象類，給各個功能創建一個對應的工廠類，然后在這個工廠類里面去創建對應的實例。　　優點：滿足開放-封閉原則　　缺點：當新增一個功能類，就需要創建對于的工廠類，相比簡單工廠模式，免去了判斷創建那個具體實例，但會創建過多的類，還不如策略模式。

代碼

　　此處利用”+”,”-“,”*”,”/”這4個Operation來生成不同的Operation對象來說明工廠方法模式，注意與簡單工廠模式的區別。

C++代碼

　　文件構成：　　—include 　　——Operation.h 　　——Add.h 　　——Subtraction.h 　　——Multiply.h 　　——Division.h 　　——OperationFactory.h 　　——AddFactory.h 　　——SubtractionFactory.h 　　——MultiplyFactory.h 　　——DivisionFactory.h 　　—src 　　——Add.cpp 　　——Subtraction.cpp 　　——Multiply.cpp 　　——Division.cpp 　　——AddFactory.cpp 　　——SubtractionFactory.cpp 　　——MultiplyFactory.cpp 　　——DivisionFactory.cpp

　　代碼如下：　　—include/Operation.h

#ifndef _OPERATION_H_#define _OPERATION_H_class Operation{public: virtual double GetResult(double A, double B)=0;};#endif

　　—include/Add.h

#ifndef _ADD_H_#define _ADD_H_#include"Operation.h"class Add:public Operation{public: double GetResult(double A, double B);};#endif

　　 —include/Subtraction.h

#ifndef _SUBTRACTION_H_#define _SUBTRACTION_H_#include"Operation.h"class Subtraction:public Operation{public: double GetResult(double A, double B);};#endif

　　 —include/Multiply.h

#ifndef _MULTIPLY_H_#define _MULTIPLY_H_#include"Operation.h"class Multiply:public Operation{public: double GetResult(double A, double B);};#endif

　　 —include/Division.h

#ifndef _DIVISION_H_#define _DIVISION_H_#include"Operation.h"class Division:public Operation{public: double GetResult(double A, double B);};#endif

　　—include/OperationFactory.h

#ifndef _OPERATIONFACTORY_H_#define _OPERATIONFACTORY_H_#include"Operation.h"class OperationFactory{public: virtual Operation* CreateInstance()=0;};#endif

　　—include/AddFactory.h

#ifndef _ADDFACTORY_H_#define _ADDFACTORY_H_#include"OperationFactory.h"class AddFactory:public OperationFactory{public: Operation* CreateInstance();};#endif

　　—include/SubtractionFactory.h

#ifndef _SUBTRACTIONFACTORY_H_#define _SUBTRACTIONFACTORY_H_#include"OperationFactory.h"class SubtractionFactory:public OperationFactory{public: Operation* CreateInstance();};#endif

　　—include/MultiplyFactory.h

#ifndef _MULTIPLYFACTORY_H_#define _MULTIPLYFACTORY_H_#include"OperationFactory.h"class MultiplyFactory:public OperationFactory{public: Operation* CreateInstance();};#endif

　　—include/DivisionFactory.h

#ifndef _DIVISIONFACTORY_H_#define _DIVISIONFACTORY_H_#include"OperationFactory.h"class DivisionFactory:public OperationFactory{public: Operation* CreateInstance();};#endif

　　—src/Add.cpp

#include"Add.h"double Add::GetResult(double A, double B){ return A+B;}

　　—src/Subtraction.cpp

#include"Subtraction.h"double Subtraction::GetResult(double A, double B){ return A-B;}

　　—src/Multiply.cpp

#include"Multiply.h"double Multiply::GetResult(double A, double B){ return A*B;}

　　—src/Division.cpp

#include"Division.h"double Division::GetResult(double A, double B){ return A-B;}

　　—src/AddFactory.cpp

#include"AddFactory.h"#include"Add.h"Operation* AddFactory::CreateInstance(){ return new Add();}

　　—src/SubtractionFactory.cpp

#include"SubtractionFactory.h"#include"Subtraction.h"Operation* SubtractionFactory::CreateInstance(){ return new Subtraction();}

　　—src/MultiplyFactory.cpp

#include"MultiplyFactory.h"#include"Multiply.h"Operation* MultiplyFactory::CreateInstance(){ return new Multiply();}

　　—src/DivisionFactory.cpp

#include<iostream>#include"AddFactory.h"#include"SubtractionFactory.h"#include"MultiplyFactory.h"#include"DivisionFactory.h"using namespace std;int main(){ double value1=10; double value2=2; OperationFactory* addFac=new AddFactory(); Operation* add=addFac->CreateInstance(); OperationFactory* subFac=new SubtractionFactory(); Operation* sub=subFac->CreateInstance(); OperationFactory* mulFac=new MultiplyFactory(); Operation* mul=mulFac->CreateInstance(); OperationFactory* divFac=new DivisionFactory(); Operation* div=divFac->CreateInstance(); cout<<"Add Operation: "<<"value1: "<<value1<<" "<<"value2: "<<value2<<" "<<"ans: "<<add->GetResult(value1,value2)<<endl; cout<<"Subtraction Operation: "<<"value1: "<<value1<<" "<<"value2: "<<value2<<" "<<"ans: "<<sub->GetResult(value1,value2)<<endl; cout<<"Multiply Operation: "<<"value1: "<<value1<<" "<<"value2: "<<value2<<" "<<"ans: "<<mul->GetResult(value1,value2)<<endl; cout<<"Division Operation: "<<"value1: "<<value1<<" "<<"value2: "<<value2<<" "<<"ans: "<<div->GetResult(value1,value2)<<endl; delete add; delete addFac; delete sub; delete subFac; delete mul; delete mulFac; delete div; delete divFac; return 0;}

Python代碼

　　文件構成：　　—Operation.py 　　—OperationFactory.py 　　代碼如下：　　—Operation.py

# -*- coding:utf-8 -*-class Operation(): def GetResult(self, A, B): passclass Add(Operation): def GetResult(self, A, B): return A + Bclass Subtraction(Operation): def GetResult(self, A, B): return A - B class Multiply(Operation): def GetResult(self, A, B): return A * Bclass Division(Operation): def GetResult(self, A, B): return A / B

　　—OperationFactory.py

# -*- coding:utf-8 -*-from Operation import *class OperationFactory(): def CreateInstance(self): passclass AddFactory(OperationFactory): def CreateInstance(self): return Add()class SubtractionFactory(OperationFactory): def CreateInstance(self): return Subtraction()class MultiplyFactory(OperationFactory): def CreateInstance(self): return Multiply()class DivisionFactory(OperationFactory): def CreateInstance(self): return Division()if "__main__" == __name__: addFac = AddFactory() addOp = addFac.CreateInstance() subFac = SubtractionFactory() subOp = subFac.CreateInstance() mulFac = MultiplyFactory() mulOp = mulFac.CreateInstance() divFac = DivisionFactory() divOp = divFac.CreateInstance() value1 = 10. value2 = 2.