? ? ? ? 建造者模式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。建造这模式是一种对象创建型模式。
myclass.h
//
// Created by yuwp on 2024/1/12.
//
#ifndef DESIGNPATTERNS_MYCLASS_H
#define DESIGNPATTERNS_MYCLASS_H
#include <iostream>
class Product {
};
class Builder {
public:
virtual void buildPartA() = 0;
virtual void buildPartB() = 0;
virtual void buildPartC() = 0;
virtual Product *getResult();
protected:
Product *m_product;
};
class ConcreteBuilder : public Builder { // 具体建造者，负责产品的具体建造过程
public:
void buildPartA() override;
void buildPartB() override;
void buildPartC() override;
};
class Director { // 指挥者，负责指挥建造者进行产品建造
public:
Director(Builder *builder);
Product *construct();
private:
Builder *m_builder;
};
#endif //DESIGNPATTERNS_MYCLASS_H
myclass.cpp
//
// Created by yuwp on 2024/1/12.
//
#include "myclass.h"
Product* Builder::getResult() {
return m_product;
}
void ConcreteBuilder::buildPartA() {
std::cout << "ConcreteBuilder构建A部分" << std::endl;
}
void ConcreteBuilder::buildPartB() {
std::cout << "ConcreteBuilder构建B部分" << std::endl;
}
void ConcreteBuilder::buildPartC() {
std::cout << "ConcreteBuilder构建C部分" << std::endl;
}
Director::Director(Builder *builder) {
m_builder = builder;
}
Product* Director::construct() {
if (m_builder) {
m_builder->buildPartA();
m_builder->buildPartC();
m_builder->buildPartB();
return m_builder->getResult();
}
return nullptr;
}main.cpp
#include <iostream>
#include <mutex>
#include "myclass.h"
int main() {
Builder *builder = new ConcreteBuilder();
Director *director = new Director(builder);
Product *product = director->construct();
delete builder;
delete director;
delete product;
return 0;
}? ? ? ? 优点：
? ? ? ? 1.?在建造者模式中，客户端不必知道产品内部组成的细节，将产品本身与产品的创建过程解耦，使得相同的创建过程可以创建不同的产品对象。
? ? ? ? 2.?每个具体建造者都相对独立，而与其他具体建造者无关。因此，可以很方便地替换具体建造者或增加新的具体建造者，用户使用不同的具体建造者即可得到不同的产品对象。由于指挥者类针对抽象建造者编程，增加新的具体建造者无须修改原有类库的代码，系统扩展方便，符合开闭原则。
? ? ? ? 3.?可以更加精细地控制产品的创建过程。将复杂产品的创建步骤分解在不同的方法中，使得创建过程更加清晰，也更方便使用程序来控制创建过程。
? ? ? ? 缺点：
? ? ? ? 1.?建造者模式所创建的产品一般具有较多的共同点，其组成部分相似。如果产品之间的差异性很大，例如很多组成部分都不相同，就不适合使用建造者模式，因此其使用范围受到一定的限制。
? ? ? ? 2.?如果产品的内部结构复杂且多变，可能会需要定义很多具体建造者类来实现这种变化，这就导致系统变得很庞大，增加系统的理解难度和运行成本。
? ? ? ? 适用场景：
? ? ? ? 1.?需要生成的产品对象有复杂的内部结构，这些产品对象通常包含多个成员变量。
? ? ? ? 2.?需要生成的产品对象的属性相互依赖，需要指定其生成顺序。
? ? ? ? 3.?对象的创建过程独立于创建该对象的类。在建造者模式中通过引入指挥者类，将创建过程封装在指挥者类中，而不在建造者类和客户类中。
? ? ? ? 4.?隔离复杂对象的创建和使用，并使得相同的创建过程可以创建不同的产品。
myclass.h
//
// Created by yuwp on 2024/1/12.
//
#ifndef DESIGNPATTERNS_MYCLASS_H
#define DESIGNPATTERNS_MYCLASS_H
#include <iostream>
class VideoPlayer {
public:
const std::string &getMMode() const;
void setMMode(const std::string &mMode);
bool isMIsShowMenu() const;
void setMIsShowMenu(bool mIsShowMenu);
bool isMIsPlayList() const;
void setMIsPlayList(bool mIsPlayList);
bool isMIsMainWindow() const;
void setMIsMainWindow(bool mIsMainWindow);
bool isMIsController() const;
void setMIsController(bool mIsController);
bool isMIsCollectList() const;
void setMIsCollectList(bool mIsCollectList);
void play();
private:
std::string m_mode;
bool m_isShowMenu;
bool m_isPlayList;
bool m_isMainWindow;
bool m_isController;
bool m_isCollectList;
};
class VideoPlayerBuilder {
public:
VideoPlayerBuilder();
~VideoPlayerBuilder();
virtual void buildMode() = 0;
virtual void buildMenu() = 0;
virtual void buildPlayList() = 0;
virtual void buildMainWindow() = 0;
virtual void buildController() = 0;
virtual void buildCollectList() = 0;
VideoPlayer *construct();
protected:
VideoPlayer *m_player;
};
class CompletePlayerBuiler : public VideoPlayerBuilder {
public:
void buildMode() override;
void buildMenu() override;
void buildPlayList() override;
void buildMainWindow() override;
void buildController() override;
void buildCollectList() override;
};
class SimplePlayerBuilder : public VideoPlayerBuilder {
public:
void buildMode() override;
void buildMenu() override;
void buildPlayList() override;
void buildMainWindow() override;
void buildController() override;
void buildCollectList() override;
};
class MemoryPlayerBuilder : public VideoPlayerBuilder {
public:
void buildMode() override;
void buildMenu() override;
void buildPlayList() override;
void buildMainWindow() override;
void buildController() override;
void buildCollectList() override;
};
#endif //DESIGNPATTERNS_MYCLASS_H
myclass.cpp
//
// Created by yuwp on 2024/1/12.
//
#include "myclass.h"
const std::string &VideoPlayer::getMMode() const {
return m_mode;
}
void VideoPlayer::setMMode(const std::string &mMode) {
m_mode = mMode;
}
bool VideoPlayer::isMIsShowMenu() const {
return m_isShowMenu;
}
void VideoPlayer::setMIsShowMenu(bool mIsShowMenu) {
m_isShowMenu = mIsShowMenu;
}
bool VideoPlayer::isMIsPlayList() const {
return m_isPlayList;
}
void VideoPlayer::setMIsPlayList(bool mIsPlayList) {
m_isPlayList = mIsPlayList;
}
bool VideoPlayer::isMIsMainWindow() const {
return m_isMainWindow;
}
void VideoPlayer::setMIsMainWindow(bool mIsMainWindow) {
m_isMainWindow = mIsMainWindow;
}
bool VideoPlayer::isMIsController() const {
return m_isController;
}
void VideoPlayer::setMIsController(bool mIsController) {
m_isController = mIsController;
}
bool VideoPlayer::isMIsCollectList() const {
return m_isCollectList;
}
void VideoPlayer::setMIsCollectList(bool mIsCollectList) {
m_isCollectList = mIsCollectList;
}
void VideoPlayer::play() {
std::cout << "------ " << getMMode() << " ------" << std::endl;
if (m_isShowMenu) {
std::cout << "显示菜单" << std::endl;
}
if (m_isPlayList) {
std::cout << "显示播放列表" << std::endl;
}
if (m_isMainWindow) {
std::cout << "显示主窗口" << std::endl;
}
if (m_isController) {
std::cout << "显示控制条" << std::endl;
}
if (m_isCollectList) {
std::cout << "显示收藏列表" << std::endl;
}
}
VideoPlayerBuilder::VideoPlayerBuilder() {
m_player = new VideoPlayer();
}
VideoPlayerBuilder::~VideoPlayerBuilder() {
if (m_player) {
delete m_player;
}
}
VideoPlayer* VideoPlayerBuilder::construct() {
buildMode();
buildMenu();
buildPlayList();
buildMainWindow();
buildController();
buildCollectList();
return m_player;
}
void CompletePlayerBuiler::buildMode() {
m_player->setMMode("完整模式");
}
void CompletePlayerBuiler::buildMenu() {
m_player->setMIsShowMenu(true);
}
void CompletePlayerBuiler::buildPlayList() {
m_player->setMIsPlayList(true);
}
void CompletePlayerBuiler::buildMainWindow() {
m_player->setMIsMainWindow(true);
}
void CompletePlayerBuiler::buildController() {
m_player->setMIsController(true);
}
void CompletePlayerBuiler::buildCollectList() {
m_player->setMIsCollectList(false);
}
void SimplePlayerBuilder::buildMode() {
m_player->setMMode("精简模式");
}
void SimplePlayerBuilder::buildMenu() {
m_player->setMIsShowMenu(false);
}
void SimplePlayerBuilder::buildPlayList() {
m_player->setMIsPlayList(false);
}
void SimplePlayerBuilder::buildMainWindow() {
m_player->setMIsMainWindow(true);
}
void SimplePlayerBuilder::buildController() {
m_player->setMIsController(true);
}
void SimplePlayerBuilder::buildCollectList() {
m_player->setMIsCollectList(false);
}
void MemoryPlayerBuilder::buildMode() {
m_player->setMMode("记忆模式");
}
void MemoryPlayerBuilder::buildMenu() {
m_player->setMIsShowMenu(false);
}
void MemoryPlayerBuilder::buildPlayList() {
m_player->setMIsPlayList(false);
}
void MemoryPlayerBuilder::buildMainWindow() {
m_player->setMIsMainWindow(true);
}
void MemoryPlayerBuilder::buildController() {
m_player->setMIsController(true);
}
void MemoryPlayerBuilder::buildCollectList() {
m_player->setMIsCollectList(true);
}
main.cpp
#include <iostream>
#include <mutex>
#include "myclass.h"
int main() {
VideoPlayerBuilder *builder = new CompletePlayerBuiler();
VideoPlayer *player = builder->construct();
player->play();
delete builder;
builder = new SimplePlayerBuilder();
player = builder->construct();
player->play();
delete builder;
builder = new MemoryPlayerBuilder();
player = builder->construct();
player->play();
delete builder;
return 0;
}