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Java > Open Source Codes > com > db4o > config > ObjectTranslator


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.config;
22
23 import com.db4o.*;
24
25 /**
26  * translator interface to translate objects on storage and activation.
27  * <br><br><b>Examples: ../com/db4o/samples/translators.</b><br><br>
28  * By writing classes that implement this interface, it is possible to
29  * define how application classes are to be converted to be stored more efficiently.
30  * <br><br>
31  * Before starting a db4o session, translator classes need to be registered. An example:<br>
32  * <code>
33  * Configuration config = Db4o.configure();<br>
34  * ObjectClass oc = config.objectClass("package.className");<br>
35  * oc.translate(new FooTranslator());</code><br><br>
36  *
37  */
38 public interface ObjectTranslator {
39
40     /**
41      * db4o calls this method during storage and query evaluation.
42      * @param container the ObjectContainer used
43      * @param applicationObject the Object to be translated
44      * @return return the object to store.<br>It needs to be of the class
45      * {@link #storedClass storedClass()}.
46      */
47     public Object JavaDoc onStore(ObjectContainer container, Object JavaDoc applicationObject);
48
49     /**
50      * db4o calls this method during activation.
51      * @param container the ObjectContainer used
52      * @param applicationObject the object to set the members on
53      * @param storedObject the object that was stored
54      */
55     public void onActivate(ObjectContainer container, Object JavaDoc applicationObject, Object JavaDoc storedObject);
56
57     /**
58      * return the Class you are converting to.
59      * @return the Class of the object you are returning with the method
60      * {@link #onStore onStore()}
61      */
62      public Class JavaDoc storedClass ();
63 }
64
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