抽象工厂的初次尝试 （(15c++ Homework) polymorphic and OOP design pattern Abstract Factory）

  首先介绍我通过这题所理解的抽象工厂：所谓抽象工厂，就是把一些类看做工厂类，专门用来new产品类，而产品类所要实现的就是构造函数，和一些简单的方法。这种写法的好处在于，有效地提高了代码的封装性，符合面向对象的需求。

下面是题目的代码。

Client.cpp

#include <iostream>#include <string> #include "Factory.hpp"#include "Product.hpp" int main() {  UIFactory* ui = 0;   int choose;   std::cin >> choose;   switch (choose) {    case 0:      ui = new MFCUIFactory();      break;    case 1:      ui = new GtkUIFactory();      break;    case 2:    default:      ui = new QtUIFactory();  }   /* Use the factory to build interface. */  Window* toolbox = ui->getToolboxWindow();  Window* layers = ui->getLayersWindow();  Window* main = ui->getMainWindow();   /* See what have we recieved. */  std::cout << toolbox->getToolkit() << ":" << toolbox->getType() << std::endl;  std::cout << layers->getToolkit() << ":" << layers->getType() << std::endl;  std::cout << main->getToolkit() << ":" << main->getType() << std::endl;   ui->deleteWindow(toolbox);  ui->deleteWindow(layers);  ui->deleteWindow(main);   delete ui;}

从中可以分辨出， Window这个类，明显是通过其他类的方法所生成的，那么Window这个类就是产品类（Product），而生成它的类，就是工厂类（factory）

factory,hpp

#ifndef FACTORY#define FACTORY#include "Product.hpp" class UIFactory { public:  virtual Window* getToolboxWindow() = 0;  virtual Window* getLayersWindow() = 0;  virtual Window* getMainWindow() = 0;  void deleteWindow(Window* w) {    if (w != NULL) {      delete w;    }  }}; /* Factory for Gtk toolkit */class GtkUIFactory : public UIFactory { public:  Window* getToolboxWindow() { return new GtkToolboxWindow(); }  Window* getLayersWindow() { return new GtkLayersWindow(); }  Window* getMainWindow() { return new GtkMainWindow(); }}; /* Factory for Qt toolkit */class QtUIFactory : public UIFactory { public:  Window* getToolboxWindow() { return new QtToolboxWindow(); }  Window* getLayersWindow() { return new QtLayersWindow(); }  Window* getMainWindow() { return new QtMainWindow(); }}; /* Factory for MFC toolkit */class MFCUIFactory : public UIFactory { public:  Window* getToolboxWindow() { return new MFCToolboxWindow(); }  Window* getLayersWindow() { return new MFCLayersWindow(); }  Window* getMainWindow() { return new MFCMainWindow(); }}; #endif

Product.hpp

#ifndef PRODUCT#define PRODUCT #include <iostream>#include <string> class Window { protected:  int width;  int height;  std::string toolkit;  std::string type;   Window(std::string usedToolkit, std::string windowType)      : toolkit(usedToolkit), type(windowType) {}  public:  virtual ~Window() {}  std::string getToolkit() { return toolkit; }  std::string getType() { return type; }}; class GtkToolboxWindow : public Window { public:  GtkToolboxWindow() : Window("Gtk", "ToolboxWindow") {}}; class GtkLayersWindow : public Window { public:  GtkLayersWindow() : Window("Gtk", "LayersWindow") {}}; class GtkMainWindow : public Window { public:  GtkMainWindow() : Window("Gtk", "MainWindow") {}}; class QtToolboxWindow : public Window { public:  QtToolboxWindow() : Window("Qt", "ToolboxWindow") {}}; class QtLayersWindow : public Window { public:  QtLayersWindow() : Window("Qt", "LayersWindow") {}}; class QtMainWindow : public Window { public:  QtMainWindow() : Window("Qt", "MainWindow") {}}; class MFCToolboxWindow : public Window { public:  MFCToolboxWindow() : Window("MFC", "ToolboxWindow") {}}; class MFCLayersWindow : public Window { public:  MFCLayersWindow() : Window("MFC", "LayersWindow") {}}; class MFCMainWindow : public Window { public:  MFCMainWindow() : Window("MFC", "MainWindow") {}}; #endif

以上是+7大神的十分透彻的代码， 但是一开始我对这个的理解不透彻，故此只是实现了功能，但是没有体现出抽象工厂，毕竟提前了太多。

一下是我的实现方法

My.hpp

#include <iostream>using namespace std;class Window {    public:    string kit;    string type;    Window(string _kit, string _type) {        kit = _kit;        type = _type;    }    string getToolkit() {return kit;}    string getType() {return type;}};class UIFactory {    public:    virtual Window* getToolboxWindow() =0;    virtual Window* getLayersWindow() =0;    virtual Window* getMainWindow() =0;    void deleteWindow(Window *type) {        delete type;    }};class MFCUIFactory : public UIFactory {    virtual Window* getToolboxWindow() {        Window* a = new Window("MFC", "ToolboxWindow");        return a;    }    virtual Window* getLayersWindow() {        Window* a = new Window("MFC", "LayersWindow");        return a;    }    virtual Window* getMainWindow() {        Window* a = new Window("MFC", "MainWindow");        return a;    }};class GtkUIFactory : public UIFactory {    virtual Window* getToolboxWindow() {        Window* a = new Window("Gtk", "ToolboxWindow");        return a;    }    virtual Window* getLayersWindow() {        Window* a = new Window("Gtk", "LayersWindow");        return a;    }    virtual Window* getMainWindow() {        Window* a = new Window("Gtk", "MainWindow");        return a;    }};class QtUIFactory : public UIFactory {    virtual Window* getToolboxWindow() {        Window* a = new Window("Qt", "ToolboxWindow");        return a;    }    virtual Window* getLayersWindow() {        Window* a = new Window("Qt", "LayersWindow");        return a;    }    virtual Window* getMainWindow() {        Window* a = new Window("Qt", "MainWindow");        return a;    }};

我的代码不够优美， 很多地方可以直接一句 return new Window("xxx", "xxx"); 

可以解决的，但是多写了一些。

总的来说这题不难，主要是在于掌握抽象工厂的概念。