/* This file is part of the db4o object database http://www.db4o.com

Copyright (C) 2004 - 2010  Versant Corporation http://www.versant.com

db4o is free software; you can redistribute it and/or modify it under
the terms of version 3 of the GNU General Public License as published
by the Free Software Foundation.

db4o is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License along
with this program.  If not, see http://www.gnu.org/licenses/. */
using Db4objects.Db4o.Foundation;
using Db4objects.Db4o.Internal;
using Db4objects.Db4o.Internal.Btree;

namespace Db4objects.Db4o.Internal.Btree
{
	/// <exclude></exclude>
	public class BTreeAdd : BTreePatch
	{
		public BTreeAdd(Transaction transaction, object obj) : base(transaction, obj)
		{
		}

		protected virtual object RolledBack(BTree btree)
		{
			btree.NotifyRemoveListener(new TransactionContext(_transaction, GetObject()));
			return No4.Instance;
		}

		public override string ToString()
		{
			return "(+) " + base.ToString();
		}

		public override object Commit(Transaction trans, BTree btree, BTreeNode node)
		{
			if (_transaction == trans)
			{
				return GetObject();
			}
			return this;
		}

		public override BTreePatch ForTransaction(Transaction trans)
		{
			if (_transaction == trans)
			{
				return this;
			}
			return null;
		}

		public override object Key(Transaction trans)
		{
			if (_transaction != trans)
			{
				return No4.Instance;
			}
			return GetObject();
		}

		public override object Rollback(Transaction trans, BTree btree)
		{
			if (_transaction == trans)
			{
				return RolledBack(btree);
			}
			return this;
		}

		public override bool IsAdd()
		{
			return true;
		}

		public override int SizeDiff(Transaction trans)
		{
			return _transaction == trans ? 1 : 0;
		}
	}
}
