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.ext;
22:
23: /**
24: * interface to the internal reference that an ObjectContainer
25: * holds for a stored object.
26: */
27: public interface ObjectInfo {
28:
29: /**
30: * returns the internal db4o ID.
31: */
32: public long getInternalID();
33:
34: /**
35: * returns the object that is referenced.
36: * <br><br>This method may return null, if the object has
37: * been garbage collected.
38: * @return the referenced object or null, if the object has
39: * been garbage collected.
40: */
41: public Object getObject();
42:
43: /**
44: * returns a UUID representation of the referenced object.
45: * UUID generation has to be turned on, in order to be able
46: * to use this feature:
47: * {@link com.db4o.config.Configuration#generateUUIDs(int)}
48: * @return the UUID of the referenced object.
49: */
50: public Db4oUUID getUUID();
51:
52: /**
53: * returns the transaction serial number ("version") the
54: * referenced object was stored with last.
55: * Version number generation has to be turned on, in order to
56: * be able to use this feature:
57: * {@link com.db4o.config.Configuration#generateVersionNumbers(int)}
58: * @return the version number.
59: */
60: public long getVersion();
61:
62: }
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