建造者(生成器)模式(Builder)是用于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。
在建造者模式中主要拥有以下角色:
Builder: 为创建产品各个部分,统一抽象接口
CouncreteBuilder: 具体的创建产品的各个部分
Director: 构造一个使用Builder接口的对象
Product: 表示被构造的复杂对象
以下代码以建造房子为例,对建造者模式进行举例说明:
Builder.h
#pragma once
#include<iostream>
#include<string>
class House
{
public:
void setDoor(std::string door) { m_door = door; }
void setWall(std::string wall) { m_wall = wall; }
void setWindow(std::string window) { m_window = window; }
std::string getDoor(void) { return m_door ; }
std::string getWall(void) { return m_wall ; }
std::string getWindow(void) { return m_window ; }
private:
std::string m_door;
std::string m_wall;
std::string m_window;
protected:
};
// 抽象的建造者
class Builder
{
public:
virtual void buildDoor() = 0;
virtual void buildWall() = 0;
virtual void buildWindow() = 0;
virtual House* getHouse() = 0;
private:
protected:
};
// 具体的建造者,公寓建造者
class FlatBuilder: public Builder
{
public:
FlatBuilder() { m_house = new House; };
~FlatBuilder() { delete m_house; };
void buildDoor() { m_house->setDoor("公寓门"); }
void buildWall() { m_house->setWall("公寓地板"); }
void buildWindow() { m_house->setWindow("公寓窗户"); }
House* getHouse() { return m_house; }
private:
House * m_house;
protected:
};
// 具体的建造者,别墅建造者
class VillaBuilder : public Builder
{
public:
VillaBuilder() { m_house = new House; };
~VillaBuilder() { delete m_house; };
void buildDoor() { m_house->setDoor("别墅门"); }
void buildWall() { m_house->setWall("别墅地板"); }
void buildWindow() { m_house->setWindow("别墅窗户"); }
House* getHouse() { return m_house; }
private:
House * m_house;
protected:
};
class Director
{
public:
Director(Builder* builder){m_builder = builder;}
~Director() { delete m_builder; }
void Construct()
{
m_builder->buildWall();
m_builder->buildDoor();
m_builder->buildWindow();
}
private:
Builder * m_builder;
protected:
};
Builder.cpp
#include "Builder.h"
mainTest.cpp
#include<iostream>
#include"Builder.h"
int main(void)
{
// 实例化一个工程队和一个设计师
VillaBuilder* villaBuilder = new VillaBuilder;
Director* director = new Director(villaBuilder);
// 让工程师指挥工程队施工
director->Construct();
// 施工队完成房子建造
House* house = villaBuilder->getHouse();
// 查看施工队完成建造的房子
std::cout<<house->getWall()<<std::endl;
std::cout << house->getDoor() << std::endl;
std::cout << house->getWindow() << std::endl;
delete house;
FlatBuilder* flatBuilder = new FlatBuilder;
director = new Director(flatBuilder);
director->Construct();
house = flatBuilder->getHouse();
// 查看施工队完成建造的房子
std::cout << house->getWall() << std::endl;
std::cout << house->getDoor() << std::endl;
std::cout << house->getWindow() << std::endl;
delete house;
delete villaBuilder;
delete flatBuilder;
delete director;
system("pause");
return 0;
}