命令设计模式

//只有在需要撤销或恢复功能时，写为命令模式才用意义。
namespace ConsoleApplication1
{
 //摘要：
 //当一个请求被封装为对象时，从而使得可以用不同的请求对客户端进行参数化；对请求排队或记录请求日志，以及支持撤销的操作。
 public abstract class CommandPattern
 {
  protected Hashtable hash;

  protected Receiver receiver;

  public CommandPattern(Receiver r)
  {
   receiver = r;
  }

  public abstract void Excute();

  public abstract void RollBack();

  public abstract void SortCommand();
 }

 public class ConcreteCommand : CommandPattern
 {
  public ConcreteCommand(Receiver r) : base(r) { }

  public override void Excute()
  {
   receiver.Action();
  }

  public override void RollBack()
  {
   throw new NotImplementedException();
  }

  public override void SortCommand()
  {
   throw new NotImplementedException();
  }
 }

 //摘要：
 //命令的执行者
 public class Receiver
 {
  public void Action()
  {
   Console.WriteLine("I am excuting an command!");
  }
 }

 //摘要：
 //发出命令的对象
 public class Invoker
 {
  private CommandPattern command;

  public void SetCommand(CommandPattern c)
  {
   this.command = c;
  }

  public void EecudeCommand()
  {
   this.command.Excute();
  }
 }

 public class Client
 {
  public void Test()
  {
   Receiver r = new Receiver();
   CommandPattern c = new ConcreteCommand(r);
   Invoker q = new Invoker();
   q.SetCommand(c);
   q.EecudeCommand();
  }
  
 }
}