Imports System Imports System.Threading Imports System.Text Imports System.Windows.Forms
Public Class MainClass
Public Shared Sub Main() Dim Tom As New Philosopher("Tom") Dim Bob As New Philosopher("Bob") Dim aThreadStart As New ThreadStart(AddressOf Tom.Eat) Dim aThread As New Thread(aThreadStart)
aThread.Name = "Tom"
Dim bThreadStart As New ThreadStart(AddressOf Bob.Eat) Dim bThread As New Thread(bThreadStart)
bThread.Name = "Bob"
aThread.Start()
bThread.Start() End Sub
End Class
Public Class Fork Private Shared mForkAvailable As Boolean = True Private Shared OwnerName As String = "Nobody"
Public Sub GrabFork(ByVal a As Philosopher)
Console.WriteLine(Thread.CurrentThread.Name & " trying to grab the fork.")
Console.WriteLine(Me.OwnerName & " has the fork.")
Monitor.Enter(Me) 'SyncLock (aFork) ' If mForkAvailable Then
a.HasFork = True
OwnerName = a.MyName
mForkAvailable = False
Console.WriteLine(a.MyName & " just got the fork, waiting")
Thread.Sleep(100) End If
Monitor.Exit(Me) 'End SyncLock End Sub End Class
Public Class Knife Private Shared mKnifeAvailable As Boolean = True Private Shared OwnerName As String = "Nobody"
Public Sub GrabKnife(ByVal a As Philosopher)
Console.WriteLine(Thread.CurrentThread.Name & " trying to grab the knife.")
Console.WriteLine(Me.OwnerName & " has the knife.")
Monitor.Enter(Me) 'SyncLock (aKnife) ' If mKnifeAvailable Then
mKnifeAvailable = False
a.HasKnife = True
OwnerName = a.MyName
Console.WriteLine(a.MyName & " just got the knife, waiting")
Thread.Sleep(100) End If
Monitor.Exit(Me) End Sub End Class Public Class Philosopher Public MyName As String Private Shared mFork As Fork Private Shared mKnife As Knife Public HasKnife As Boolean Public HasFork As Boolean
Shared Sub New()
mFork = New Fork()
mKnife = New Knife() End Sub Public Sub New(ByVal theName As String)
MyName = theName End Sub
Public Sub Eat()
Do Until Me.HasKnife And Me.HasFork
Console.WriteLine(Thread.CurrentThread.Name & " is in the thread.") If Rnd() < 0.5 Then
mFork.GrabFork(Me)
Else
mKnife.GrabKnife(Me) End If
Loop
MessageBox.Show(Me.MyName & " can eat!")
mKnife = New Knife()
mFork = New Fork() End Sub End Class
