Oracle Advance Queue or Advanced Queuing from .NET (C#/VB/MC++)

//
//  THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY
//  KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
//  IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR
//  PURPOSE. IT CAN BE DISTRIBUTED FREE OF CHARGE AS LONG AS THIS HEADER 
//  REMAINS UNCHANGED.
//
//  Email:  gustavo_franco@hotmail.com
//
//  Copyright (C) 2005 Franco, Gustavo 
//
using System;
using System.Threading;
using System.Windows.Forms;

using AQLib;
using DBTypes;

namespace OracleAQ
{
	public class PreConsumer : AQConsumer	
	{
		#region Variables Declaration
		private int	mPerformanceCounter = 0;
		
		//All the following data can be filled before the payload is called,
		//When payload arrive this info can be use to help payload to be procesed.
		private string mInternalInformation = "";
		#endregion

		#region Constructors
		public PreConsumer()
		{
		}
		#endregion

		#region Properties
		public string InternalInformation
		{
			get{return mInternalInformation;}
			set{mInternalInformation = value;}
		}
		#endregion

		#region Methods
		public override void ProcessPayload(object payload)
		{
			try
			{
				if (Form1.MainInstance != null && !Form1.MainInstance.IsDisposing)
					Form1.MainInstance.AddItemToMessagesList(
						"Got a payload with type: [" + payload.GetType().FullName + 
						"] HashCode: [" + payload.GetHashCode() + 
						"] Thread Id: [" + Thread.CurrentThread.GetHashCode() +
						"] Counter: [" + (mPerformanceCounter++) + "] and extra info is [" +
						mInternalInformation +
						"]");

				// Lets add a little delay between (0 and 2 secons) to allow dispatcher see that this consumer 
				// is busy and send next message to different consumer.
				Thread.Sleep(new Random().Next(2000));

				// THIS IS HOW IN REAL LIFE WILL BE, YOU WILL CAST THE INCOMING PAYLOAD TO THE EXPECTED TYPE
				// AFTER THAT YOU CAN START PROCESS IT.
				// Tm_Message_Payload_Ty tm_payload = (Tm_Message_Payload_Ty) payload;
			}
			catch(AQException ex)
			{
				if (Form1.MainInstance != null)
					Form1.MainInstance.ShowAQExceptionMessage(ex);
			}
			catch(Exception ex)
			{
				//This will happend when user close the main form without Stop Producer first.
				//OnClosing event call producer stop, but it is too late because now Form1 has to wait
				//for all consumer to finish, means the message queue is stopped, and so this consumer cannot 
				//insert a message in the list box then it is a dead lock.
				//On real life this will never happend if you finalize the producer properly, also in real life 
				//usually the Main Form is not used to interactive with consumers.
				if (ex.GetType() == typeof(System.Threading.ThreadAbortException))
					return;

				//There are several ways to finish it properly, but if I get ObjectDisposedException is beacuse
				//User closed the form when consumers still were running.
				//Just ignore this error... (see above)
				if (ex.GetType() == typeof(System.ObjectDisposedException))
					return;

				if (Form1.MainInstance != null)
					Form1.MainInstance.ShowExceptionMessage(ex);
			}
		}
		#endregion
	}
}