浅尝DesignPattern_Proxy

UML:

Proxy   (MathProxy)

• maintains a reference that lets the proxy access the real subject. Proxy may refer to a Subject if the RealSubject and Subject interfaces are the same.
• 维持一个引用让代理访问真正的Subject。代理可以引用一个Subject，如果RealSubject和Subject接口是相同的。
• provides an interface identical to Subject's so that a proxy can be substituted for for the real subject.
• 提供等同于Subject 的接口,这样代理就能替代真正的Subject 
• controls access to the real subject and may be responsible for creating and deleting it.
• 控制进入真正的Subject 而且负责创建和删除它
• other responsibilites depend on the kind of proxy:其他责任取决于代理的类型
  • remote proxies are responsible for encoding a request and its arguments and for sending the encoded request to the real subject in a different address space.
  • 远程代理是负责编码空间的要求，其参数和真正的问题在一个不同的地址编码发送请求。
  • virtual proxies may cache additional information about the real subject so that they can postpone accessing it. For example, the ImageProxy from the Motivation caches the real images's extent.
  • 虚拟代理可缓存的其他信息的真正Subject ，使他们可以推迟访问它。例如，ImageProxy的用处就是缓存实际图像的。
  • protection proxies check that the caller has the access permissions required to perform a request.
  • 保护代理检查调用方拥有访问权限的规定要求执行。

Subject   (IMath)

• defines the common interface for RealSubject and Proxy so that a Proxy can be used anywhere a RealSubject is expected.
• 定义RealSubject和代理的共同界面，使代理可以在任何地方使用RealSubject。

RealSubject   (Math)

• defines the real object that the proxy represents. 
• 定义了真正的对象，是代理代表的对象。

Sample:

IMath.cs

 

1 public interface IMath
2 {
3 double Add(double x, double y);
4 double Sub(double x, double y);
5 double Mul(double x, double y);
6 double Div(double x, double y);
7 }

 

 

 

Math.cs

 

1 class Math:IMath
2 {
3 #region IMath 成员
4
5 public double Add(double x, double y)
6 {
7 return x + y;
8 }
9
10 public double Sub(double x, double y)
11 {
12 return x - y;
13 }
14
15 public double Mul(double x, double y)
16 {
17 return x * y;
18 }
19
20 public double Div(double x, double y)
21 {
22 return x / y;
23 }
24
25 #endregion
26 }

 

 

MathProxy.cs

1 class MathProxy:IMath
2 {
3 private Math math = new Math();
4 #region IMath 成员
5
6 public double Add(double x, double y)
7 {
8 return math.Add(x, y);
9 }
10
11 public double Sub(double x, double y)
12 {
13 return math.Sub(x, y);
14 }
15
16 public double Mul(double x, double y)
17 {
18 return math.Mul(x, y);
19 }
20
21 public double Div(double x, double y)
22 {
23 return math.Div(x, y);
24 }
25
26 #endregion
27 }

 

Program.cs

1 #region Proxy
2 MathProxy proxy = new MathProxy();
3 Console.WriteLine("4 + 2 = " + proxy.Add(4, 2));
4 Console.WriteLine("4 - 2 = " + proxy.Sub(4, 2));
5 Console.WriteLine("4 * 2 = " + proxy.Mul(4, 2));
6 Console.WriteLine("4 / 2 = " + proxy.Div(4, 2));
7 #endregion

 

转载于:https://www.cnblogs.com/TivonStone/archive/2010/04/24/1719294.html