C＃3.0 - 监视器的应用 - 建议

为了解监视器，我实现了下面的代码。但我不确定代码是否线程安全。C＃3.0 - 监视器的应用 - 建议

namespace MonitorExample 
{ 
    public delegate void WaterLevelInformer(object sender,WaterLevelArgs e); 

    class WaterLevelListener 
    { 
     //listener will print information 
     // when WaterTank is reaching its empty level or full 
     public void ShowResult(object sender, WaterLevelArgs e) 
     { 
      Console.WriteLine("Water Level is :{0}", e.Level); 
     } 
    } 

    class WaterTank 
    { 
     //starting level is empty 
     static int level=0; 
     //capacity of the WaterTank is 2000 liters 
     const int capacity = 2000; 
     private WaterLevelListener lst = new WaterLevelListener(); 

     public event WaterLevelInformer levelHandler; 

     public WaterTank(WaterLevelListener lstn) 
     { 
      this.lst = lstn; 
      this.levelHandler +=new WaterLevelInformer(lst.ShowResult); 
     } 

     public void FillWater() 
     { 
      lock (this) 
      { 
       if (level >= capacity) 
       { 
        Monitor.Wait(this); 
       } 
       Console.WriteLine("....WaterTank is gettig filled..."); 
       for (int i = 100; i <= 2000; i+=100) 
       { 
        Console.WriteLine("Current Water Level {0}", i); 
        level = i; 
        Thread.Sleep(1000); 
        if (i == 1700) 
        { 
         WaterLevelInformation(level); 
         Thread.Sleep(1000); 
        } 
       } 

       Monitor.Pulse(this); 
      } 
     } 

     public void ConsumeWater() 
     { 
      lock (this) 
      { 
       if (level<=0) 
       { 
        Monitor.Wait(this); 
       } 
       Console.WriteLine("...Water is being consumed...."); 
       for (int i =2000; i >= 0; i -= 100) 
       { 
        Console.WriteLine("Current Water Level {0}", i); 
        Thread.Sleep(1000); 
        level = i; 
        if (i == 100) 
        { 
         WaterLevelInformation(i); 
         Thread.Sleep(1000); 
        } 
       } 

       Monitor.Pulse(this); 
      } 
     } 

     //WaterLevelInformation is used to raise the event 
     // When WaterTank reaching its empty level 
     //or WaterTank is full 
     public void WaterLevelInformation(int i) 
     { 
      if (levelHandler != null) 
      { 
       WaterLevelArgs waterArgs=new WaterLevelArgs(i); 
       levelHandler(this,waterArgs); 
      } 
     } 
    } 

    // WaterLevelArgs class stores the level of 
    // the water 
    public class WaterLevelArgs : EventArgs 
    { 
     public int Level 
     { 
      get; 
      set; 
     } 
     public WaterLevelArgs(int level) 
     { 
      Level = level; 
     } 
    } 

    class WaterLevelSimulator 
    { 

     static void Main() 
     { 
      WaterLevelListener lst = new WaterLevelListener(); 
      WaterTank tnk = new WaterTank(lst); 
      Thread thd1 = new Thread(new ThreadStart(tnk.ConsumeWater)); 
      Thread thd2 = new Thread(new ThreadStart(tnk.FillWater)); 
      thd1.Start(); 
      thd2.Start(); 
      Console.ReadKey(); 
     } 
    } 

}

问题：

1）是上面的代码是线程安全的？

2）由于C＃2.0和3.0引入了Action <>，Predicate <>，lambdas我该如何改进我的代码？

3）什么是最好的方式我可以为了使用出版商，Observer模式可循，我的意思是我应该需要单独设计类（I）定制的EventArgs （II）监听（三）发行（iv）链接器 - （链接监听器，发布者，自定义EventArgs）？

来源

2009-11-26 user215675