zhexuejia.txt

哲学家进餐问题实现

//DiningPhilosophers.cs----------code:seafrog----------------------------------------------------- 
using System; 
using System.Threading; 
using System.Windows.Forms; 

using seafrog.Threading; 
using seafrog.Philosopher; 

namespace DiningPhilosophers 
{ 
public class Form1 : System.Windows.Forms.Form 
{ 
private System.Windows.Forms.Button button1; 
private System.ComponentModel.Container components = null; 
private System.Windows.Forms.ListBox listBox1; 
private Philosopher[] p=new Philosopher[5]; 
public Form1() 
{ 
InitializeComponent(); 

Mutex[] chopSticks=new Mutex[5]; 
for(int i=0;i<5;i++) 
{ 
chopSticks[i]=new Mutex(false); 
} 
for(int i=0;i<5;i++) 
{ 
PhilosopherData pd; 
pd.PhilosopherId=i; 
pd.RightChopStick=chopSticks[(i+1)%5]; 
pd.LeftChopStick=chopSticks[(i+4)%5]; 
pd.AmountToEat=5; 
pd.TotalFood=35; 
p[i]=new Philosopher(pd); 
p[i].MessageArrival+=new Philosopher.MessageArrivedHandler(ShowMessage); 
} 
} 
protected override void Dispose( bool disposing ) 
{ 
if( disposing ) 
{ 
if (components != null) 
{ 
components.Dispose(); 
} 
} 
base.Dispose( disposing ); 
} 

#region Windows Form Designer generated code 

private void InitializeComponent() 
{ 
this.button1 = new System.Windows.Forms.Button(); 
this.listBox1 = new System.Windows.Forms.ListBox(); 
this.SuspendLayout(); 
// 
// button1 
// 
this.button1.Location = new System.Drawing.Point(8, 224); 
this.button1.Name = "button1"; 
this.button1.Size = new System.Drawing.Size(272, 40); 
this.button1.TabIndex = 1; 
this.button1.Text = "Go To Restaurant"; 
this.button1.Click += new System.EventHandler(this.button1_Click); 
// 
// listBox1 
// 
this.listBox1.ItemHeight = 12; 
this.listBox1.Name = "listBox1"; 
this.listBox1.Size = new System.Drawing.Size(296, 220); 
this.listBox1.TabIndex = 2; 
// 
// Form1 
// 
this.AutoScaleBaseSize = new System.Drawing.Size(6, 14); 
this.ClientSize = new System.Drawing.Size(292, 273); 
this.Controls.AddRange(new System.Windows.Forms.Control[] { 
this.listBox1, 
this.button1}); 
this.Name = "Form1"; 
this.Text = "Form1"; 
this.ResumeLayout(false); 

} 
#endregion 
[STAThread] 
static void Main() 
{ 
Application.Run(new Form1()); 
} 

private void button1_Click(object sender, System.EventArgs e) 
{ 
for(int i=0;i<5;i++) 
p[i].Start(); 
} 

public void ShowMessage(object sender,MessageArrivedEventArgs e) 
{ 
switch(e.type) 
{ 
case Philosopher.READY: 
listBox1.Items.Add("Philosopher("+e.philosopherData.PhilosopherId+") ready."); 
break; 
case Philosopher.EATING: 
listBox1.Items.Add("Philosopher("+ 
e.philosopherData.PhilosopherId+") eating "+ 
e.philosopherData.AmountToEat+" of "+ 
e.philosopherData.TotalFood+" food."); 
break; 
case Philosopher.THINKING: 
listBox1.Items.Add("Philosopher("+e.philosopherData.PhilosopherId+") thinking."); 
break; 
case Philosopher.FINISHED: 
listBox1.Items.Add("Philosopher("+e.philosopherData.PhilosopherId+") finished."); 
break; 
} 
} 
} 
} 

//BaseThread.cs----------code:seafrog-------------------------------------------------------- 
using System; 
using System.Threading; 
namespace seafrog.Threading 
{ 
//工作线程抽象类，作为对线程操作的封装。 
public abstract class WorkerThread 
{ 
private object ThreadData; 
private Thread thisThread; 

public object Data 
{ 
get{return ThreadData;} 
set{ThreadData=value;} 
} 
public object IsAlive 
{ 
get{return thisThread==null?false:thisThread.IsAlive;} 
} 
public WorkerThread(object data) 
{ 
this.ThreadData=data; 
} 
public WorkerThread() 
{ 
ThreadData=null; 
} 
public void Start() 
{ 
thisThread=new Thread(new ThreadStart(this.Run)); 
thisThread.Start(); 
} 
public void Stop() 
{ 
thisThread.Abort(); 
while(thisThread.IsAlive); 
thisThread=null; 
} 
protected abstract void Run(); 
} 
} 

//Philosophers.cs----------code:seafrog-------------------------------------------------------- 
using System; 
using System.Threading; 
using seafrog.Threading; 
namespace seafrog.Philosopher 
{ 
//封装哲学家数据的结构 
public struct PhilosopherData 
{ 
public int PhilosopherId; 
public Mutex RightChopStick; 
public Mutex LeftChopStick; 
public int AmountToEat; 
public int TotalFood; 
} 

public class Philosopher : seafrog.Threading.WorkerThread 
{ 
public const int READY=0; 
public const int EATING=1; 
public const int THINKING=2; 
public const int FINISHED=3; 

public Philosopher(object data):base(data){} 
public delegate void MessageArrivedHandler(Object sender,MessageArrivedEventArgs args); 
public event MessageArrivedHandler MessageArrival; 
public static int finished=0; 

protected override void Run() 
{ 
PhilosopherData pd=(PhilosopherData)Data; 
Random r=new Random(pd.PhilosopherId); 
MessageArrival(this,new MessageArrivedEventArgs(READY,pd)); 
WaitHandle[] chopSticks=new WaitHandle[]{pd.LeftChopStick,pd.RightChopStick}; 

while(pd.TotalFood>0) 
{ 
//如果两边的哲学家拿着筷子，则等待。 
WaitHandle.WaitAll(chopSticks); 
//否则，吃饭。 
MessageArrival(this,new MessageArrivedEventArgs(EATING,pd)); 
//把饭吃掉一部分。 
pd.TotalFood-=pd.AmountToEat; 
Thread.Sleep(r.Next(1000,5000)); 

MessageArrival(this,new MessageArrivedEventArgs(THINKING,pd)); 
//放下左边和右边的筷子。 
pd.RightChopStick.ReleaseMutex(); 
pd.LeftChopStick.ReleaseMutex(); 

Thread.Sleep(r.Next(1000,5000)); 
} 
//饭都吃完了。 
MessageArrival(this,new MessageArrivedEventArgs(FINISHED,pd)); 
if(++finished==4) 
System.Windows.Forms.MessageBox.Show("All Finished!"); 
} 
} 

//事件：用来通知主窗体现在哲学家的状态。 
public class MessageArrivedEventArgs : EventArgs 
{ 
public int type; 
public PhilosopherData philosopherData; 
public MessageArrivedEventArgs(int t,PhilosopherData pd) 
{ 
type=t; 
philosopherData=pd; 
} 
} 
}