设计模式读书笔记：Builder（建造者）

2015-07-03 11:11:52

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意图：

将一个复杂对象的构建与它的表示分离，使得同样的构建过程可以创建不同的表示。

结构图：来自《23种设计模式 - 郗晓勇》

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

Product

#include <iostream>

namespace NS_BUILDER {

class Product {
public:
	Product() : _color("none"), _size("none") {}
	virtual ~Product() {}

	void printSelf(void)
	{
		std::cout << "Build color: " << _color << " size: " << _size << std::endl;
	}

	void setColor(std::string color)	{ _color = color; }
	void setSize(std::string size)	{ _size = size; }

private:
	std::string _color;
	std::string _size;
};

} /* namespace NS_BUILDER */

Builder

#include <iostream>

namespace NS_BUILDER {

class Builder {
public:
	Builder() {}
	virtual ~Builder() {}

	virtual void setColor(std::string color) = 0;
	virtual void setSize(std::string size) = 0;
};

} /* namespace NS_BUILDER */

ConcreteBuilderA

#include "Product.h"
#include "Builder.h"

namespace NS_BUILDER {

class ConcreteBuilderA : public Builder
{
public:
	ConcreteBuilderA()
	{
		_product = new Product();
	}
	virtual ~ConcreteBuilderA() {}

	virtual void setColor(std::string color)
	{
		// do nothing
	}
	virtual void setSize(std::string size)
	{
		_product->setSize(size);
	}
	Product *getIgnoreColorProduct(void)
	{
		return _product;
	}

private:
	Product *_product;
};

} /* namespace NS_BUILDER */

ConcreteBuilderB

#include "Product.h"
#include "Builder.h"

namespace NS_BUILDER {

class ConcreteBuilderB : public Builder
{
public:
	ConcreteBuilderB()
	{
		_product = new Product();
	}
	virtual ~ConcreteBuilderB() {}

	virtual void setColor(std::string color)
	{
		_product->setColor(color);
	}
	virtual void setSize(std::string size)
	{
		_product->setSize(size);
	}
	Product *getCareColorProduct(void)
	{
		return _product;
	}

private:
	Product *_product;
};

} /* namespace NS_BUILDER */

Director

namespace NS_BUILDER {

class Builder;
class Director {
public:
	Director(Builder *builder) : _builder(builder) {}
	virtual ~Director() {}
	void Build(void);

private:
	Builder *_builder;
};

} /* namespace NS_BUILDER */

#include "Director.h"
#include "Builder.h"

namespace NS_BUILDER {

void Director::Build(void)
{
	// 可能配置中读出来的属性
	_builder->setColor("red");
	_builder->setSize("big");
}

} /* namespace NS_BUILDER */

main

#include "Builder/Director.h"
#include "Builder/ConcreteBuilderA.h"
#include "Builder/ConcreteBuilderB.h"
#include "Builder/Product.h"
using namespace NS_BUILDER;
int main(void)
{
	ConcreteBuilderB *builder = new ConcreteBuilderB();
	Director *director = new Director(builder);
	director->Build();

	Product *product = builder->getCareColorProduct();
	product->printSelf();

	delete builder;
	delete director;
	delete product;
}

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