设计模式读书笔记：Factory Method（工厂方法）

2015-07-03 11:28:46

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意图：

定义一个用于创建对象的接口，让子类决定实例化哪一个类。Factory Method 使一个类的实例化延迟到其子类。

结构图：来自《23种设计模式 - 郗晓勇》

实现：https://github.com/panshiqu/patterns/tree/master/FactoryMethod

Creator

namespace NS_FACTORY_METHOD {

class Product;
class Creator {
public:
	Creator() {}
	virtual ~Creator() {}
	virtual Product *createProduct(void) = 0;
};

template <class TheProduct>
class StandardCreator : public Creator {
public:
	StandardCreator() {}
	virtual ~StandardCreator() {}
	virtual Product *createProduct(void);
};

template <class TheProduct>
Product *StandardCreator<TheProduct>::createProduct(void) {
	return new TheProduct;
}

} /* namespace NS_FACTORY_METHOD */

Product

namespace NS_FACTORY_METHOD {

class Product {
public:
	Product() {}
	virtual ~Product() {}
	virtual void printSelf(void) = 0;
};

} /* namespace NS_FACTORY_METHOD */

ConcreteProduct

#include <iostream>

#include "Creator.h"
#include "Product.h"

namespace NS_FACTORY_METHOD {

class ConcreteProduct : public Product
{
public:
	ConcreteProduct() {}
	virtual ~ConcreteProduct() {}
	virtual void printSelf(void)
	{
		std::cout << "ConcreteProduct" << std::endl;
	}
};

StandardCreator<ConcreteProduct> ConcreteCreator;

} /* namespace NS_FACTORY_METHOD */

main

#include "FactoryMethod/ConcreteProduct.h"
using namespace NS_FACTORY_METHOD;
int main(void)
{
	Product *product = ConcreteCreator.createProduct();
	product->printSelf();
	delete product;
}

附加：