漫谈设计模式之享元模式（Flyweight）

#include <iostream>
#include <map>
#include <iterator>

using namespace std;

/**
* @brief The Person class
* 享元对象
*/
class Person
{
public:
Person(string name,int age) {
m_name = name;
m_age = age;
}

virtual ~Person() {}
virtual void printType()=0;

protected:
string m_name;
int m_age;
};

/**
* @brief The Teacher class
* 享元细粒度对象
*/
class Teacher : public Person
{
public:
Teacher(string id,string name,int age) : Person(name, age) {
m_id = id;
}

void printType() {
cout<<"name:"<<m_name<<" age:"<<m_age<<" id:"<<m_id<<endl;
}

private:
string m_id;

};

/**
* @brief The FlyWeightFactory class
* 享元工厂，在这个案例中我们通过享元工厂要获得
* 的享元细粒度对象是Teacher
*/
class FlyWeightFactory
{
public:
FlyWeightFactory() {
m_map.clear();
}

~FlyWeightFactory() {
while(!m_map.empty()) {
Person* tmp = NULL;
map<string , Person*>::iterator it = m_map.begin();

tmp = it->second;
m_map.erase(it);  //把结点从map容器中删除
delete tmp;
}
}

Person* getTeacher(string id) {
Person* tmp = NULL;
map<string ,Person*>::iterator it;
it = m_map.find(id);
if(it == m_map.end()) { //没有找到相同id的老师
string name;
int age;
cout<<"请输入老师的名字："<<endl;
cin>>name;
cout<<"请输入老师的年龄："<<endl;
cin>>age;
tmp = new Teacher(id,name,age);
m_map.insert(pair<string,Person*>(id,tmp));

} else {
tmp = it->second;
}

return tmp;
}

private:
map<string ,Person*> m_map;
};

int main(int /*argc*/, char */*argv*/[])
{

Person* p1 = NULL;
Person* p2 = NULL;
FlyWeightFactory* fwf = new FlyWeightFactory;
p1 = fwf->getTeacher("001");
p1->printType();

p2 = fwf->getTeacher("001");
p2->printType();

delete fwf;
fwf = NULL;

return 0;
}