Kerosene ORM: a dynamic, configuration-less and self-adaptive ORM for POCO objects supporting a SQL-like syntax from C#

// ======================================================== 
namespace Kerosene.ORM.Direct.Concrete
{
	using Kerosene.ORM.Core;
	using Kerosene.ORM.Core.Concrete;
	using System;
	using System.Data;
	using System.Transactions;

	// ==================================================== 
	/// <summary>
	/// Represents a nestable transaction in a direct connection scenario.
	/// </summary>
	public class KTransactionDirect : KTransactionBase, IKTransactionDirect
	{
		IDbTransaction _DbTransaction = null;
		TransactionScope _TransactionScope = null;
		bool _LinkOpenedByTransaction = false;
		int _Level = 0;

		internal KTransactionDirect(IKLinkDirect link, KTransactionMode mode) : base(link, mode) { }

		protected override void OnDispose(bool disposing)
		{
			if (!IsDisposed && disposing) { }
			base.OnDispose(disposing);
		}

		/// <summary>
		/// Gets the direct link this transaction is associated with.
		/// </summary>
		public new IKLinkDirect Link
		{
			get { return (IKLinkDirect)base.Link; }
		}
		IKLink IKTransaction.Link
		{
			get { return this.Link; }
		}

		/// <summary>
		/// Gets the active database transaction in use by this instance, or null.
		/// </summary>
		public IDbTransaction DbTransaction
		{
			get { return _DbTransaction; }
		}

		/// <summary>
		/// Gets the active transaction scope in use by this instance, or null.
		/// </summary>
		public TransactionScope TransactionScope
		{
			get { return _TransactionScope; }
		}

		/// <summary>
		/// Starts a new physical transaction, or if it was already active, increases its nesting level.
		/// </summary>
		public override void Start()
		{
			if (IsDisposed) throw new ObjectDisposedException(this.ToString());
			if (Link == null) throw new InvalidOperationException(string.Format("This '{0}' is not associated with any link.", this));
			if (Link.IsDisposed) throw new ObjectDisposedException(Link.ToString());

			if (_Level > 0) _Level++;
			else
			{
				if (Mode == KTransactionMode.Database)
				{
					if (!Link.IsOpen) { Link.Open(); _LinkOpenedByTransaction = true; }
					_DbTransaction = Link.Connection.BeginTransaction();
				}
				if (Mode == KTransactionMode.GlobalScope)
				{
					_TransactionScope = new TransactionScope();
					if (!Link.IsOpen) { Link.Open(); _LinkOpenedByTransaction = true; }
				}
				_Level = 1;
			}
		}

		/// <summary>
		/// Commits the underlying physical transaction, or if it nesting level is greater than one, decreases it.
		/// <para>This method is merely ignored is the transaction was not active.</para>
		/// </summary>
		public override void Commit()
		{
			if (IsDisposed) throw new ObjectDisposedException(this.ToString());
			if (Link == null) throw new InvalidOperationException(string.Format("This '{0}' is not associated with any link.", this));
			if (Link.IsDisposed) throw new ObjectDisposedException(Link.ToString());

			if (_Level == 0) return;
			if (_Level == 1)
			{
				if (Mode == KTransactionMode.Database)
				{
					_DbTransaction.Commit(); _DbTransaction.Dispose(); _DbTransaction = null;
					if (_LinkOpenedByTransaction) { Link.Close(); _LinkOpenedByTransaction = false; }
				}
				if (Mode == KTransactionMode.GlobalScope)
				{
					_TransactionScope.Complete(); _TransactionScope.Dispose(); _TransactionScope = null;
					if (_LinkOpenedByTransaction) { Link.Close(); _LinkOpenedByTransaction = false; }
				}
				_Level = 0;
			}
			else _Level--;
		}

		/// <summary>
		/// Aborts the underlying physical transaction regardless of the nesting level of this instance.
		/// <para>This method is merely ignored is the transaction was not active.</para>
		/// </summary>
		public override void Abort()
		{
			if (IsDisposed) return;
			if (Link == null || Link.IsDisposed) return;

			if (_DbTransaction != null)
			{
				_DbTransaction.Rollback(); _DbTransaction.Dispose(); _DbTransaction = null;
				if (_LinkOpenedByTransaction) Link.Close();
			}
			if (_TransactionScope != null)
			{
				_TransactionScope.Dispose(); _TransactionScope = null;
				if (_LinkOpenedByTransaction) Link.Close();
			}

			_LinkOpenedByTransaction = false;
			_Level = 0;
		}

		/// <summary>
		/// Gets the nesting level of this transaction. A value of cero indicates that this transaction is not
		/// active.
		/// </summary>
		public override int Level
		{
			get { return _Level; }
		}
	}
}
// ========================================================