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.cluster;
22:
23: import com.db4o.*;
24: import com.db4o.internal.cluster.*;
25: import com.db4o.query.*;
26:
27: /**
28: * allows running Queries against multiple ObjectContainers.
29: * @exclude
30: */
31: public class Cluster {
32:
33: public final ObjectContainer[] _objectContainers;
34:
35: /**
36: * use this constructor to create a Cluster and call
37: * add() to add ObjectContainers
38: */
39: public Cluster(ObjectContainer[] objectContainers) {
40: if (objectContainers == null) {
41: throw new NullPointerException();
42: }
43: if (objectContainers.length < 1) {
44: throw new IllegalArgumentException();
45: }
46: for (int i = 0; i < objectContainers.length; i++) {
47: if (objectContainers[i] == null) {
48: throw new IllegalArgumentException();
49: }
50: }
51: _objectContainers = objectContainers;
52: }
53:
54: /**
55: * starts a query against all ObjectContainers in
56: * this Cluster.
57: * @return the Query
58: */
59: public Query query() {
60: synchronized (this ) {
61: Query[] queries = new Query[_objectContainers.length];
62: for (int i = 0; i < _objectContainers.length; i++) {
63: queries[i] = _objectContainers[i].query();
64: }
65: return new ClusterQuery(this , queries);
66: }
67: }
68:
69: /**
70: * returns the ObjectContainer in this cluster where the passed object
71: * is stored or null, if the object is not stored to any ObjectContainer
72: * in this cluster
73: * @param obj the object
74: * @return the ObjectContainer
75: */
76: public ObjectContainer objectContainerFor(Object obj) {
77: synchronized (this ) {
78: for (int i = 0; i < _objectContainers.length; i++) {
79: if (_objectContainers[i].ext().isStored(obj)) {
80: return _objectContainers[i];
81: }
82: }
83: }
84: return null;
85: }
86:
87: }
|