抽象工厂模式

【1】什么是抽象工厂模式？

为创建一组相关或相互依赖的对象提供一个接口，而且无需指定他们的具体类

【2】抽象工厂模式的代码示例：

代码示例：

#include <iostream>
#include <string>
using namespace std;

class IUser
{
public:
    virtual void getUser() = 0;
    virtual void setUser() = 0;
};

class SqlUser : public IUser
{
public:
    void getUser()
    {
        cout << "在sql中返回user" << endl;
    }
    void setUser()
    {
        cout << "在sql中设置user" << endl;
    }
};

class AccessUser : public IUser
{
public:
    void getUser()
    {
        cout << "在Access中返回user" << endl;
    }
    void setUser()
    {
        cout << "在Access中设置user" << endl;
    }
};

class IDepartment
{
public:
    virtual void getDepartment() = 0;
    virtual void setDepartment() = 0;
};

class SqlDepartment : public IDepartment
{
public:
    void getDepartment()
    {
        cout << "在sql中返回Department" << endl;
    }
    void setDepartment()
    {
        cout << "在sql中设置Department" << endl;
    }
};

class AccessDepartment : public IDepartment
{
public:
    void getDepartment()
    {
        cout << "在Access中返回Department" << endl;
    }
    void setDepartment()
    {
        cout << "在Access中设置Department" << endl;
    }
};

class IFactory
{
public:
    virtual IUser *createUser() = 0;
    virtual IDepartment *createDepartment() = 0;
};

class SqlFactory : public IFactory
{
public:
    IUser *createUser() 
    {
        return new SqlUser();
    }
    IDepartment *createDepartment() 
    {
        return new SqlDepartment();
    }
};

class AccessFactory : public IFactory
{
public:
    IUser *createUser()
    {
        return new AccessUser();
    }
    IDepartment *createDepartment() 
    {
        return new AccessDepartment();
    }
};

/*************************************************************/

class DataAccess
{
private:
    static string db;
public:
    static IUser *createUser()
    {
        if (db == "access")
        {
            return new AccessUser();
        }
        else if (db == "sql")
        {
            return new SqlUser();
        }
    }
    static IDepartment *createDepartment()
    {
        if (db == "access")
        {
            return new AccessDepartment();
        }
        else if (db == "sql")
        {
            return new SqlDepartment();
        }    
    }
};

string DataAccess::db = "sql";

/*************************************************************/

int main()
{
    IFactory *factory;
    IUser *user;
    IDepartment *department;

    factory = new AccessFactory();
    user = factory->createUser();
    department = factory->createDepartment();
    
    user->getUser();
    user->setUser();
    department->getDepartment();
    department->setDepartment();

    user = DataAccess::createUser();
    department = DataAccess::createDepartment();

    user->getUser();
    user->setUser();
    department->getDepartment();
    department->setDepartment();

    return 0;
}

http://www.cnblogs.com/Braveliu/p/3946808.html