/// <summary>
/// Callback function to process read's server' replies
/// <param name="IAsyncResult"A AsyncResult Delgate Object.</param>
/// </summary>
public static void CallbackRead(IAsyncResult ar)
{
RemoteAsyncReadDelegate del = (RemoteAsyncReadDelegate)((AsyncResult)ar).AsyncDelegate;
lock (ReadLock)
{
//Only care about one reply, ignore others
if (_responseRead == null)
{
_responseRead = del.EndInvoke(ar);
readHandles[0].Set();
}
}
}
public Tuple Read(Tuple tuple)
{
readHandles = new AutoResetEvent[1];
readHandles[0] = new AutoResetEvent(false);
View actualView = this.GetView();
List <ITupleSpaceXL> serversObj = new List <ITupleSpaceXL>();
List <string> toRemove = new List <string>();
ITupleSpaceXL tupleSpace = null;
_responseRead = null;
//save remoting objects of all members of the view
foreach (string serverPath in actualView.Servers)
{
try
{
tupleSpace = (ITupleSpaceXL)Activator.GetObject(typeof(ITupleSpaceXL), serverPath);
tupleSpace.ItemCount(); //just to check availability of the server
}
catch (System.Net.Sockets.SocketException) {
tupleSpace = null;
toRemove.Add(serverPath);
}
if (tupleSpace != null)
{
serversObj.Add(tupleSpace);
}
}
if (serversObj.Count > 0)
{
foreach (string crashed in toRemove)
{
//only one can crash so serverObj is obviously online
_view = serversObj[0].Remove(crashed);
}
}
else
{
Console.WriteLine("All servers are dead! Exiting...");
Environment.Exit(1);
}
foreach (ITupleSpaceXL server in serversObj)
{
try
{
RemoteAsyncReadDelegate RemoteDel = new RemoteAsyncReadDelegate(server.read);
AsyncCallback RemoteCallback = new AsyncCallback(CallbackRead);
IAsyncResult RemAr = RemoteDel.BeginInvoke(tuple, CallbackRead, null);
}
catch (System.Net.Sockets.SocketException) { Console.WriteLine("** FRONTEND READ: Cannot invoke read on server!"); }
}
while (_responseRead == null)
{
Console.WriteLine("** FRONTEND READ: Not yet receive any reply let me wait...");
WaitHandle.WaitAny(readHandles);
}
_requestId++;
Console.WriteLine("** FRONTEND READ: Here is a response: " + _responseRead);
return(_responseRead);
}
