设计模式之代理类

//抽象类 
public abstract class Subject 
{
     public abstract void Request(); 
}

// 实际类RealSubject 
public override void Request() 
{ 
    Console.WriteLine("is realsubject request");
 } 

//代理类 
class Proxy:Subject 
{ 
    RealSubject realSubject; 
    public override void Request() 
    {
         if (realSubject == null) 
        {
             realSubject = new RealSubject(); 
        }
         realSubject.Request(); 
    } 
} 
//客户端：
 Proxy proxy = new Proxy(); proxy.Request();     

个人体会：客户端调用了代理类，实际上调用的是实际类。