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Java > Open Source Codes > com > db4o > foundation > Collection4Iterator


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.foundation;
22
23 /**
24  * @exclude
25  */
26 public class Collection4Iterator extends Iterator4Impl {
27
28     private final Collection4 _collection;
29     private final int _initialVersion;
30
31     public Collection4Iterator(Collection4 collection, List4 first) {
32         super(first);
33         _collection = collection;
34         _initialVersion = currentVersion();
35     }
36     
37     public boolean moveNext() {
38         validate();
39         return super.moveNext();
40     }
41     
42     public Object JavaDoc current() {
43         validate();
44         return super.current();
45     }
46
47     private void validate() {
48         if (_initialVersion != currentVersion()) {
49             throw new InvalidIteratorException();
50         }
51     }
52     
53     private int currentVersion() {
54         return _collection.version();
55     }
56 }
57
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