01: /* Copyright (C) 2004 - 2007 db4objects Inc. http://www.db4o.com
02:
03: This file is part of the db4o open source object database.
04:
05: db4o is free software; you can redistribute it and/or modify it under
06: the terms of version 2 of the GNU General Public License as published
07: by the Free Software Foundation and as clarified by db4objects' GPL
08: interpretation policy, available at
09: 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.internal;
22:
23: import com.db4o.foundation.*;
24:
25: /**
26: * @exclude
27: */
28: public class LockedTree {
29:
30: private Tree _tree;
31:
32: private int _version;
33:
34: public void add(Tree tree) {
35: changed();
36: _tree = _tree == null ? tree : _tree.add(tree);
37: }
38:
39: private void changed() {
40: _version++;
41: }
42:
43: public void clear() {
44: changed();
45: _tree = null;
46: }
47:
48: public Tree find(int key) {
49: return TreeInt.find(_tree, key);
50: }
51:
52: public void read(Buffer buffer, Readable template) {
53: clear();
54: _tree = new TreeReader(buffer, template).read();
55: changed();
56: }
57:
58: public void traverseLocked(Visitor4 visitor) {
59: int currentVersion = _version;
60: Tree.traverse(_tree, visitor);
61: if (_version != currentVersion) {
62: throw new IllegalStateException();
63: }
64: }
65:
66: public void traverseMutable(Visitor4 visitor) {
67: final Collection4 currentContent = new Collection4();
68: traverseLocked(new Visitor4() {
69: public void visit(Object obj) {
70: currentContent.add(obj);
71: }
72: });
73: Iterator4 i = currentContent.iterator();
74: while (i.moveNext()) {
75: visitor.visit(i.current());
76: }
77: }
78:
79: }
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