1200字范文 > C++设计模式--抽象工厂模式

C++设计模式--抽象工厂模式

时间：2021-03-03 05:06:32

相关推荐

C++设计模式--抽象工厂模式

前言

前面有两篇文章分别介绍了简单工厂模式和工厂方法模式，这两种模式都比较常见，今天介绍工厂模式的最后一种，抽象工厂模式。

抽象工厂模式（Abstract Factory Pattern）是所有形态的工厂模式中最为抽象和最具一般性的一种形态。抽象工厂模式是指当有多个抽象角色时，使用的一种工厂模式。抽象工厂模式可以向客户端提供一个接口，使客户端在不必指定产品的具体的情况下，创建多个产品族中的产品对象。

UML 类图

来看一下抽象工厂模式的类图结构。

IFactory : 抽象工厂基类ConcreteFactory1：具体产品的工厂类，继承于IFactory，并实现基类中的产品接口ProductA ：产品基类ConcreteProductA ：具体的产品类，由具体的产品工厂创建

适用场景

可以在不必指定产品的具体的情况下，创建多个产品族中的产品对象。

示例

我们还是根据前两节的示例来进行扩展：

factory.h

#include "product.h"class IFactory{public:enum FactoryType{RECTANGLE,CIRCLE,TRIANGE};IFactory();virtual ~IFactory();virtual IShape * createShape() = 0;virtual IColor * createColor() = 0;static IFactory * createFactor(FactoryType type);};class RectangleFactory : public IFactory{public:RectangleFactory() {}~RectangleFactory();IShape * createShape();IColor * createColor();};class CircleFactory : public IFactory{public:CircleFactory() {}~CircleFactory();IShape * createShape();IColor * createColor();};class TriangeFactory : public IFactory{public:TriangeFactory() {}~TriangeFactory();IShape * createShape();IColor * createColor();};

factory.cpp

#include "factory.h"IFactory::IFactory(){}IFactory::~IFactory(){}IFactory *IFactory::createFactor(IFactory::FactoryType type){IFactory * factory = nullptr;switch (type) {case RECTANGLE:factory = new RectangleFactory();break;case CIRCLE:factory = new CircleFactory();break;case TRIANGE:factory = new TriangeFactory();break;default:break;}return factory;}RectangleFactory::~RectangleFactory(){}IShape *RectangleFactory::createShape(){return new Rectangle();}IColor *RectangleFactory::createColor(){return new RectangleColor();}CircleFactory::~CircleFactory(){}IShape *CircleFactory::createShape(){return new Circle();}IColor *CircleFactory::createColor(){return new CircleColor();}TriangeFactory::~TriangeFactory(){}IShape *TriangeFactory::createShape(){return new Triange();}IColor *TriangeFactory::createColor(){return new TriangeColor();}

product.h

#include <iostream>using namespace std;class IShape{public:IShape();virtual ~IShape();virtual void draw() = 0;};class IColor{public:IColor();virtual ~IColor();virtual void brush() = 0;};class Rectangle : public IShape{public:Rectangle(){}~Rectangle(){}void draw();};class Circle : public IShape{public:Circle(){}~Circle(){}void draw();};class Triange : public IShape{public:Triange(){}~Triange(){}void draw();};class RectangleColor : public IColor{public:RectangleColor(){}~RectangleColor(){}void brush();};class CircleColor : public IColor{public:CircleColor(){}~CircleColor(){}void brush();};class TriangeColor : public IColor{public:TriangeColor(){}~TriangeColor(){}void brush();};

product.cpp

#include "product.h"IShape::IShape(){}IShape::~IShape(){}void Triange::draw(){cout << "draw Triange.." << endl;}void Circle::draw(){cout << "draw Circle.." << endl;}void Rectangle::draw(){cout << "draw Rectangle.." << endl;}IColor::IColor(){}IColor::~IColor(){}void RectangleColor::brush(){cout << "Rectangle brush Red.."<< endl;}void CircleColor::brush(){cout << "Circle brush Blue.."<< endl;}void TriangeColor::brush(){cout << "Triange brush green.."<< endl;}

main.cpp

#include <iostream>#include "factory.h"using namespace std;#define DELETE(x) {if(x){delete(x);(x) = nullptr;}}int main(){//RectangleIFactory * pFactory = IFactory::createFactor(IFactory::RECTANGLE);IShape * pShape = pFactory->createShape();IColor * pColor = pFactory->createColor();pShape->draw();pColor->brush();DELETE(pFactory);DELETE(pShape);DELETE(pColor);//CirclepFactory = IFactory::createFactor(IFactory::CIRCLE);pShape = pFactory->createShape();pColor = pFactory->createColor();pShape->draw();pColor->brush();DELETE(pFactory);DELETE(pShape);DELETE(pColor);//TriangepFactory = IFactory::createFactor(IFactory::TRIANGE);pShape = pFactory->createShape();pColor = pFactory->createColor();pShape->draw();pColor->brush();DELETE(pFactory);DELETE(pShape);DELETE(pColor);return 0;}

从以上代码可以看到，我们要通过一个静态函数来创建不同的工厂类型，这用法有点类似简单工厂模式的用法，原理差不多的，那么在用的时候只需要传入不同类型就可以创建对应的工厂了，而在每一个具体的工厂中又会对应创建不同的产品出来。