设计模式-代理模式

普通代理：访问真实对象，通过代理对象来放问真实对象；
实现方法：
（1）创建代理对象时，传递一个真实对象的引用；
（2）在代理类内部实现，在代理类创建时，由代理类决定创建一个真实角色；

// 签字
class ISign{
public:

virtual void doSomeThing(string msg) = 0;    

};

// 老板
class Boss : public ISign{
public:

virtual void doSomeThing(string msg){
    cout << "Boss: " << msg << endl;
}    

};

// 秘书代理
class SecretaryProxy : public ISign{
public:

// 普通代理: 方法1 
SecretaryProxy(){
    boss = new Boss();
}

SecretaryProxy(Boss* boss){
    this->boss = boss;
}    

virtual void doSomeThing(string msg){
    cout << "SecretaryProxy: do pre something: " << endl;
    boss->doSomeThing(msg);
    cout << "SecretaryProxy: do after something: " << endl;
}

private:

Boss* boss;    

};

int main(){

SecretaryProxy* proxy_1 = new SecretaryProxy();
proxy_1->doSomeThing("hello");

Boss* boss = new Boss();
SecretaryProxy* proxy_2 = new SecretaryProxy(boss);
proxy_2->doSomeThing("hello");

return 0;

}