享元模式

概念

Flyweight模式也叫享元模式，是构造型模式之一，它通过与其他类似对象共享数据来减小内存占用。

角色和职责

1）抽象享元角色：
所有具体享元类的父类，规定一些需要实现的公共接口。
2）具体享元角色：
抽象享元角色的具体实现类，并实现了抽象享元角色规定的方法。
3）享元工厂角色：
负责创建和管理享元角色。

使用场景：是以共享的方式，高效的支持大量的细粒度的对象。

案例

#include <iostream>using namespace std;#include "string"#include "map"class Person{public:    Person(string name, int age, int sex)    {        this->name = name;        this->age = age;        this->sex = sex;    }    string getName()    {        return name;    }    int getAge()    {        return age;    }    int getSex()    {        return sex;    }protected:    string  name;    int     age;    int     sex; //1男 2女};class Teacher : public Person{public:    Teacher(string id, string name, int age, int sex) : Person(name, age, sex)    {        this->id = id;    }    string getId()    {        return id;    }    void printT()    {        cout << "id:" <<id << "\t" << "name:" <<name << "\t" << "age:" <<age << "\t" << "sex:" <<sex << "\t" << endl;    }private:    string id;};class TeacherFactory{public:    TeacherFactory()    {        m_tpool.empty();    }    ~TeacherFactory()    {        while (!m_tpool.empty()) //在工厂中创建老师结点，在工厂中销毁老师结点        {            Teacher *tmp = NULL;            map<string, Teacher *>::iterator it = m_tpool.begin();            tmp = it->second;            m_tpool.erase(it);            delete tmp;        }    }    //通过Teacher的pool，来存放老师结点，在TeacherFactory中创建老师、销毁老师    Teacher *getTeacher(string tid)    {        string  name;        int     age;        int     sex;        Teacher *tmp = NULL;        map<string, Teacher*>::iterator it =  m_tpool.find(tid);        if (it == m_tpool.end())        {            cout << "id为: " << tid << " 的老师不存在,系统为你创建该老师，请输入以下信息" <<endl;            cout << "请输入老师姓名：";            cin >> name;            cout << "请输入老师年龄：";            cin >> age;            cout << "请输入老师性别 1男 2女：";            cin >> sex;            tmp = new Teacher(tid, name, age, sex);            m_tpool.insert(pair<string, Teacher*>(tid, tmp));        }        else        {            tmp = (it->second);        }        return tmp;    }private:    map<string, Teacher *> m_tpool;};void main(){    /*    Teacher *t1 = new Teacher("001", "小李", 30, 1);    Teacher *t2 = new Teacher("002", "小张", 30, 1);    Teacher *t3 = new Teacher("001", "小李", 30, 1);    Teacher *t4 = new Teacher("004", "小吴", 30, 1);    //    cout << "t1 t3的 工号一样，应该是同一个人 " << endl;    delete t1;    delete t2;    delete t3;    delete t4;    */    TeacherFactory *teacherFactory = new TeacherFactory;    Teacher *t1 = teacherFactory->getTeacher("001");    t1->printT();    Teacher *t2 = teacherFactory->getTeacher("001");    t2->printT();    delete teacherFactory;    system("pause");    return ;}