Using NHibernate in COM+ (.NET Enterprise Services) Distributed Transactions

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.EnterpriseServices;
using System.Reflection;
using NHibernate;
using NHibernate.Cfg;

namespace ComPlusNHibernateTest
{
	/// <summary>
	/// Controls the use of <see cref="Table1"/> and <see cref="Table2"/>.
	/// </summary>
	[Transaction(TransactionOption.Supported)]
	public class OrmManager : ServicedComponent
	{
		private ISessionFactory _SessionFactory;
		
		/// <summary>
		/// Gets the session factory for this assembly.
		/// </summary>
		private ISessionFactory SessionFactory 
		{
			get 
			{
				if (_SessionFactory == null) 
				{
					Configuration cfg = new Configuration();
					cfg.Properties = GetConfigProps();
					cfg.AddAssembly(this.GetType().Assembly);
					_SessionFactory = cfg.BuildSessionFactory();
				}
				return _SessionFactory;
			}
		}

		public OrmManager()
		{
		}

		private Hashtable GetConfigProps() 
		{
			Hashtable props = new Hashtable();
			props.Add("hibernate.connection.provider", "NHibernate.Connection.DriverConnectionProvider");
			props.Add("hibernate.dialect", "NHibernate.Dialect.MsSql2000Dialect");
			props.Add("hibernate.connection.driver_class", "NHibernate.Driver.SqlClientDriver");
			props.Add("hibernate.connection.connection_string", ConfigurationSettings.AppSettings["ConnectionString"]);
			return props;
		}

		/// <summary>
		/// This method uses reflection to enlist in the distributed transaction.
		/// </summary>
		/// <param name="conn"></param>
		private static void EnlistIfPossible(System.Data.IDbConnection conn) 
		{
			if (ContextUtil.IsInTransaction) 
			{
				MethodInfo mi = conn.GetType().GetMethod("EnlistDistributedTransaction", BindingFlags.Public | BindingFlags.Instance);
				if (mi != null) 
				{
					mi.Invoke(conn, new object[] { (System.EnterpriseServices.ITransaction)ContextUtil.Transaction });
				}
			}
		}

		public void Save(object obj) 
		{
			ISession session = SessionFactory.OpenSession();
			try 
			{
				EnlistIfPossible(session.Connection);
				session.SaveOrUpdate(obj);
				session.Flush();
				if (ContextUtil.IsInTransaction)
					ContextUtil.MyTransactionVote = TransactionVote.Commit;
			}
			catch 
			{
				if (ContextUtil.IsInTransaction)
					ContextUtil.MyTransactionVote = TransactionVote.Abort;
				throw;
			}
			finally 
			{
				if (session != null && session.IsOpen)
					session.Close();
			}
		}

		public void Delete(object obj) 
		{
			ISession session = SessionFactory.OpenSession();
			try 
			{
				EnlistIfPossible(session.Connection);
				session.Delete(obj);
				session.Flush();
				if (ContextUtil.IsInTransaction)
					ContextUtil.MyTransactionVote = TransactionVote.Commit;
			}
			catch 
			{
				if (ContextUtil.IsInTransaction)
					ContextUtil.MyTransactionVote = TransactionVote.Abort;
				throw;
			}
			finally 
			{
				if (session != null && session.IsOpen)
					session.Close();
			}
		}

		public IList GetAll(Type t) 
		{
			ISession session = SessionFactory.OpenSession();
			try 
			{
				IList lst = session.CreateCriteria(t).List();
				return lst;
			}
			finally 
			{
				if (session != null && session.IsOpen)
					session.Close();
			}
		}
	}
}