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Java > Open Source Codes > com > db4o > inside > btree > BTreePatch


1 /* Copyright (C) 2004 - 2006 db4objects Inc. http://www.db4o.com
2
3 This file is part of the db4o open source object database.
4
5 db4o is free software; you can redistribute it and/or modify it under
6 the terms of version 2 of the GNU General Public License as published
7 by the Free Software Foundation and as clarified by db4objects' GPL
8 interpretation policy, available at
9 http://www.db4o.com/about/company/legalpolicies/gplinterpretation/
10 Alternatively you can write to db4objects, Inc., 1900 S Norfolk Street,
11 Suite 350, San Mateo, CA 94403, USA.
12
13 db4o is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 for more details.
17
18 You should have received a copy of the GNU General Public License along
19 with this program; if not, write to the Free Software Foundation, Inc.,
20 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
21 package com.db4o.inside.btree;
22
23 import com.db4o.Transaction;
24
25
26 public abstract class BTreePatch {
27     
28     protected final Transaction _transaction;
29     
30     protected Object JavaDoc _object;
31
32     public BTreePatch(Transaction transaction, Object JavaDoc obj) {
33         _transaction = transaction;
34         _object = obj;
35     }
36     
37     public abstract Object JavaDoc commit(Transaction trans, BTree btree);
38
39     public boolean isRemove() {
40         return false;
41     }
42
43     public abstract BTreePatch forTransaction(Transaction trans);
44     
45     public Object JavaDoc getObject() {
46         return _object;
47     }
48     
49     public abstract Object JavaDoc rollback(Transaction trans, BTree btree);
50     
51     public String JavaDoc toString(){
52         if(_object == null){
53             return "[NULL]";
54         }
55         return _object.toString();
56     }
57     
58     public boolean isAdd() {
59         return false;
60     }
61     
62     public abstract Object JavaDoc key(Transaction trans);
63 }
64
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