01: /*
02: * $RCSfile: IndexedObject.java,v $
03: *
04: * Copyright 2001-2008 Sun Microsystems, Inc. All Rights Reserved.
05: * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
06: *
07: * This code is free software; you can redistribute it and/or modify it
08: * under the terms of the GNU General Public License version 2 only, as
09: * published by the Free Software Foundation. Sun designates this
10: * particular file as subject to the "Classpath" exception as provided
11: * by Sun in the LICENSE file that accompanied this code.
12: *
13: * This code is distributed in the hope that it will be useful, but WITHOUT
14: * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
15: * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16: * version 2 for more details (a copy is included in the LICENSE file that
17: * accompanied this code).
18: *
19: * You should have received a copy of the GNU General Public License version
20: * 2 along with this work; if not, write to the Free Software Foundation,
21: * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
22: *
23: * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
24: * CA 95054 USA or visit www.sun.com if you need additional information or
25: * have any questions.
26: *
27: * $Revision: 1.5 $
28: * $Date: 2008/02/28 20:17:24 $
29: * $State: Exp $
30: */
31:
32: package javax.media.j3d;
33:
34: /**
35: * Class used for IndexedUnorderedList
36: */
37:
38: abstract class IndexedObject extends Object {
39:
40: /**
41: * A 2D array listIdx[3][len] is used.
42: * The entry listIdx[0][], listIdx[0][1] is used for each VirtualUniverse.
43: * The entry listIdx[2][0] is used for index to which one to use.
44: *
45: * This is used to handle the case the Node Object move from
46: * one VirtualUniverse A to another VirtualUniverse B.
47: * It is possible that another Structures in B may get the add
48: * message first before the Structures in A get the remove
49: * message to clear the entry. This cause MT problem. So a
50: * 2D array is used to resolve it.
51: */
52: int[][] listIdx;
53:
54: abstract VirtualUniverse getVirtualUniverse();
55:
56: synchronized int getIdxUsed(VirtualUniverse u) {
57: int idx = listIdx[2][0];
58: if (u == getVirtualUniverse()) {
59: return idx;
60: }
61: return (idx == 0 ? 1 : 0);
62: }
63:
64: void incIdxUsed() {
65: if (listIdx[2][0] == 0) {
66: listIdx[2][0] = 1;
67: } else {
68: listIdx[2][0] = 0;
69: }
70: }
71: }
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