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Java > Open Source Codes > org > objectweb > jalisto > se > impl > lock > AccessController


1 /*
2  * Jalisto - JAva LIght STOrage
3  * Copyright (C) 2000-2005 Xcalia http://www.xcalia.com
4  *
5  * This library is free software; you can redistribute it and/or
6  * modify it under the terms of the GNU Lesser General Public
7  * License as published by the Free Software Foundation; either
8  * version 2.1 of the License, or (at your option) any later version.
9  *
10  * This library is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13  * Lesser General Public License for more details.
14  *
15  * You should have received a copy of the GNU Lesser General Public
16  * License along with this library; if not, write to the Free Software
17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
18  *
19  * Xcalia
20  * 71, rue Desnouettes
21  * 75014 Paris - France
22  * http://www.xcalia.com
23  */
24 package org.objectweb.jalisto.se.impl.lock;
25
26 public class AccessController {
27     public AccessController() {
28         canGetAccess = new boolean[2];
29         canGetAccess[NEW_OID] = true;
30         canGetAccess[COMMIT_ROLLBACK_LOCKMANAGER] = true;
31     }
32
33     public void getAccessControl(int accessIndex) {
34         while (!getAccess(accessIndex)) {
35             Thread.yield();
36         }
37     }
38
39     private synchronized boolean getAccess(int accessIndex) {
40         if (!canGetAccess[accessIndex]) {
41             return false;
42         }
43         canGetAccess[accessIndex] = false;
44         return true;
45     }
46
47     public synchronized void releaseAccessControl(int accessIndex) {
48         canGetAccess[accessIndex] = true;
49     }
50
51     private boolean[] canGetAccess;
52
53     public final static int NEW_OID = 0;
54     public final static int COMMIT_ROLLBACK_LOCKMANAGER = 1;
55 }
56
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