--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Pml/Channels/PassivePmlChannel.cs	Tue Sep 11 16:28:53 2012 +0200
@@ -0,0 +1,59 @@
+using System;
+using UCIS.Pml;
+using System.Collections.Generic;
+using System.Threading;
+
+namespace UCIS.Pml {
+	public abstract class PassivePmlChannel : IPmlChannel {
+		private bool _isOpen = true;
+
+		public virtual bool IsOpen { get { return _isOpen; } }
+		public abstract void WriteMessage(PmlElement message);
+
+		public void Dispose() {
+			Close();
+		}
+		public virtual void Close() {
+			_isOpen = false;
+		}
+
+		public abstract PmlElement ReadMessage();
+
+		public IAsyncResult BeginReadMessage(AsyncCallback callback, object state) {
+			ReadMessageAsyncResult ar = new ReadMessageAsyncResult();
+			ar.Callback = callback;
+			ar.State = state;
+			UCIS.ThreadPool.RunCall(AsyncReadMessage, ar);
+			return ar;
+		}
+		public PmlElement EndReadMessage(IAsyncResult asyncResult) {
+			ReadMessageAsyncResult ar = (ReadMessageAsyncResult)asyncResult;
+			if (ar.Error != null) throw new Exception("The asynchronous operation could not be completed", ar.Error);
+			return ar.Message;
+		}
+
+		private struct ReadMessageAsyncResult : IAsyncResult {
+			internal object State;
+			internal PmlElement Message;
+			internal AsyncCallback Callback;
+			internal Exception Error;
+			internal bool Completed;
+
+			public bool CompletedSynchronously { get { return false; } }
+			public object AsyncState { get { return State; } }
+			public WaitHandle AsyncWaitHandle { get { return null; } }
+			public bool IsCompleted { get { return Completed; } }
+		}
+		private void AsyncReadMessage(object state) {
+			ReadMessageAsyncResult ar = (ReadMessageAsyncResult)state;
+			try {
+				ar.Message = ReadMessage();
+				ar.Error = null;
+			} catch (Exception ex) {
+				ar.Error = ex;
+			}
+			ar.Completed = true;
+			ar.Callback.Invoke(ar);
+		}
+	}
+}