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.convert;
22:
23: import com.db4o.foundation.*;
24: import com.db4o.internal.*;
25: import com.db4o.internal.convert.conversions.*;
26:
27: /**
28: * @exclude
29: */
30: public class Converter {
31:
32: public static final int VERSION = FieldIndexesToBTrees_5_7.VERSION;
33:
34: private static Converter _converter;
35:
36: private Hashtable4 _conversions;
37:
38: private Converter() {
39: _conversions = new Hashtable4();
40:
41: // TODO: There probably will be Java and .NET conversions
42: // Create Platform4.registerConversions() method ann
43: // call from here when needed.
44: CommonConversions.register(this );
45: }
46:
47: public static boolean convert(ConversionStage stage) {
48: if (!needsConversion(stage.systemData())) {
49: return false;
50: }
51: if (_converter == null) {
52: _converter = new Converter();
53: }
54: return _converter.runConversions(stage);
55: }
56:
57: private static boolean needsConversion(SystemData systemData) {
58: return systemData.converterVersion() < VERSION;
59: }
60:
61: public void register(int idx, Conversion conversion) {
62: if (_conversions.get(idx) != null) {
63: throw new IllegalStateException();
64: }
65: _conversions.put(idx, conversion);
66: }
67:
68: public boolean runConversions(ConversionStage stage) {
69: SystemData systemData = stage.systemData();
70: if (!needsConversion(systemData)) {
71: return false;
72: }
73: for (int i = systemData.converterVersion(); i <= VERSION; i++) {
74: Conversion conversion = (Conversion) _conversions.get(i);
75: if (conversion != null) {
76: stage.accept(conversion);
77: }
78: }
79: return true;
80: }
81:
82: }
|