抽象工厂模式

情景:

随着业务的扩大，原来的工厂除了生产cpu,也开始生产硬盘了。如果继续使用简单工厂模式、工厂方法模式，就有些鞭长莫及了。此时就轮到抽象工厂模式登场了。

定义:为提供一个创建一系列相关或相互依赖对象的接口，而无需指定它们具体的类(将类的实例化推迟到了子类实现)

工厂方法和抽象工厂的比较:

工厂方法模式：一个工厂只定义一个接口，负责生产一类产品

抽向工厂模式: 一个工厂定义多个相关接口，每一个接口对应生产一类产品

#include <iostream>
using namespace std;

class CPU
{
public:
    virtual void show() = 0;
    virtual ~CPU(){}  // 抽象基类的析构函数必须是虚析构，以保证delete基类指针的时候,子类的析构函数能被调用，实现内存的完全清理
};

class CPUA : public CPU
{
public:
    virtual void show()
    {
        cout << "I am CPUA" << endl;
    }
    ~CPUA()
    {
        cout << "CPUA 被析构" << endl;
    }
};

class CPUB : public CPU
{
public:
    virtual void show()
    {
        cout << "I am CPUB" << endl;
    }
    ~CPUB()
    {
        cout << "CPUB被析构" << endl;
    }
};

class HardDisk
{
public:
    virtual void show() = 0;
    virtual ~HardDisk() {}
};

class HardDiskA : public HardDisk
{
public:
    virtual void show()
    {
        cout << "I am HardDiskA" << endl;;
    }

    ~HardDiskA()
    {
        cout << "HardDiskA 被析构" << endl;
    }
};

class HardDiskB : public HardDisk
{
public:
    virtual void show()
    {
        cout << "I am HardDiskB" << endl;
    }

    ~HardDiskB()
    {
        cout << "HardDiskB 被析构" << endl;
    }
};

class Factory
{
public:
    virtual CPU * produceCPU() = 0;
    virtual HardDisk *produceHardDisk() = 0;
    virtual ~Factory() {}
};

class FactoryA : public Factory
{
public:
    virtual CPU *produceCPU()
    {
        return new CPUA();
    }

    virtual HardDisk *produceHardDisk()
    {
        return new HardDiskA();
    }

    ~FactoryA() { cout << "FactoryA被析构" << endl; }
};

class FactoryB : public Factory
{
public:
    virtual CPU *produceCPU()
    {
        return new CPUB();
    }

    virtual HardDisk *produceHardDisk()
    {
        return new HardDiskB();
    }

    ~FactoryB() { cout << "FactoryB被析构" << endl; }
};

void test()
{
    Factory *f = NULL;
    CPU *cpu = NULL;
    HardDisk *disk = NULL;
    f = new FactoryA();
    cpu = f->produceCPU();
    cpu->show();
    disk = f->produceHardDisk();
    disk->show();
    delete cpu;
    delete disk;
    delete f;
    f = new FactoryB();
    cpu = f->produceCPU();
    cpu->show();
    disk = f->produceHardDisk();
    disk->show();
    delete cpu;
    delete disk;
    delete f;
}

int main()
{
    test();
    cin.get();
    return 0;
}

效果: