设计模式-工厂模式

工厂模式

本文以下内容为芒果参考菜鸟教程-工厂模式，实现了工厂模式的c++版本以及c#版本，关于工厂模式更多的介绍可以前往菜鸟教程学习。

注：图片来源菜鸟教程

c++实现

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// Copyright https://mangoroom.cn
// License(MIT)
// Author:mango
// This is factory_patter.h

#ifndef FACTORY_PATTERN_H
#define FACTORY_PATTERN_H

#include<iostream>
#include<memory>

namespace dsignpattern
{
	// 1. ch:创建一个接口 | en: Create an interface
	class Shape
	{
	public:
		virtual void Draw() = 0;
	};

	// 2. ch:创建实现接口的实体类 | en: Create an entity class that implements an interface
	class Rectangle : public Shape
	{
	public:
		void Draw() override
		{
			std::cout << "Inside Rectangle::draw() method." << std::endl;
		}
	};

	class Square : public Shape
	{
	public:
		void Draw() override
		{
			std::cout << "Inside Square::draw() method." << std::endl;
		}
	};

	class Circle : public Shape
	{
	public:
		void Draw() override
		{
			std::cout << "Inside Circle::draw() method." << std::endl;
		}
	};

	// 3. ch:创建一个工厂，生成基于给定信息的实体类的对象 | en: Create an factory to generate objects for entity classes based on a given information
	class ShapeFactory
	{
	public:
		// ch: 使用 GetShape 函数获取形状类型的对象 | en: To get an object of a shape type using the GetShape function
		std::unique_ptr<Shape> GetShape(std::string shape_type)
		{
			if (shape_type.empty())
			{
				return nullptr;
			}
			else if (shape_type == "CIRClE")
			{
				return std::unique_ptr<Shape>(new Circle());
			}
			else if (shape_type == "RECTANGLE")
			{
				return std::unique_ptr<Shape>(new Rectangle());
			}
			else if (shape_type == "SQUARE")
			{
				return std::unique_ptr<Shape>(new Square());
			}
			else
			{
				return nullptr;
			}
		}
	};

	// 4. ch: 使用该工厂，通过传递类型信息来获取实体类的对象。 | en: Use the factory to get objects for the entity class by passing type information.
	void FactoryPatternDemo();
}

#endif // FACTORY_PATTERN_H

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// Copyright https://mangoroom.cn
// License(MIT)
// Author:mango
// This is factory_pattern.cpp

#include"factory_pattern.h"

using namespace dsignpattern;

// 4. ch: 使用该工厂，通过传递类型信息来获取实体类的对象。 | en: Use the factory to get objects for the entity class by passing type information.
void dsignpattern::FactoryPatternDemo()
{

	std::unique_ptr<ShapeFactory> shape_factory(new ShapeFactory());

	// ch: 获取 Circle 的对象，并调用它的 Draw函数 | en: Gets the object of the Circle and calls its Draw method
	std::unique_ptr<Shape> cirle(shape_factory->GetShape("CIRClE"));
	cirle->Draw();

	// ch: 获取 Rectangle的对象， 并调用它的 Draw函数 | en: Gets the object of the Rectangle and calls its method
	std::unique_ptr<Shape> rectangle(shape_factory->GetShape("RECTANGLE"));
	rectangle->Draw();

	// ch: 获取 Square的对象， 并调用它的Draw函数 | en: Gets the object of the Square and calls its method
	std::unique_ptr<Shape> square(shape_factory->GetShape("SQUARE"));
	square->Draw();
}

运行结果

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Inside Circle ::draw() method.
Inside Rectangle::draw() method.
Inside Square ::draw() method.

c#实现

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using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

// Copyright https://mangoroom.cn
// License(MIT)
// Author:mango
// DesignPattern: FactoryPatternDemo
namespace DesignPattern
{
    // 1. ch:创建一个接口 | en: Create an interface
    public interface Shape
    {
        void Draw();
    }

    // 2. ch:创建实现接口的实体类 | en: Create an entity class that implements an interface

    public class Rectangle : Shape
    {
        public void Draw()
        {
            Console.WriteLine("Inside Rectangle::draw() method.");
        }
    }

    public class Square : Shape
    {
        public void Draw()
        {
            Console.WriteLine("Inside Square ::draw() method.");
        }
    }

    public class Circle : Shape
    {
        public void Draw()
        {
            Console.WriteLine("Inside Circle ::draw() method.");
        }
    }


    // 3. ch:创建一个工厂，生成基于给定信息的实体类的对象 | en: Create an factory to generate objects for entity classes based on a given information
    public class ShapeFactory
    {
        // ch: 使用 GetShape 函数获取形状类型的对象 | en: To get an object of a shape type using the GetShape function
        public Shape GetShape(string shapeType)
        {
            if(shapeType == null)
            {
                return null;
            }

            if (shapeType.Equals("CIRCLE"))
            {
                return new Circle();
            }
            else if (shapeType.Equals("RECTANGLE"))
            {
                return new Rectangle();
            }
            else if (shapeType.Equals("SQUARE"))
            {
                return new Square();
            }
            return null;
        }
    }

    public class FactoryPatternDemo
    {
        public static void FactoryPatternRun()
        {
             ShapeFactory shapeFactory = new ShapeFactory();
 
            // ch: 获取 Circle 的对象，并调用它的 Draw函数 | en: Gets the object of the Circle and calls its Draw method
	        Shape circle = shapeFactory.GetShape("CIRCLE");
            circle.Draw();

	        // ch: 获取 Rectangle的对象， 并调用它的 Draw函数 | en: Gets the object of the Rectangle and calls its method
            Shape rectangle = shapeFactory.GetShape("RECTANGLE");
            rectangle.Draw();

	        // ch: 获取 Square的对象， 并调用它的Draw函数 | en: Gets the object of the Square and calls its method
            Shape square = shapeFactory.GetShape("SQUARE");
            square.Draw();
        }
    }
}

运行结果

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Inside Circle ::draw() method.
Inside Rectangle::draw() method.
Inside Square ::draw() method.

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