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1   /*
2    * Copyright (c) 2001, Oracle and/or its affiliates. All rights reserved.
3    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4    *
5    * This code is free software; you can redistribute it and/or modify it
6    * under the terms of the GNU General Public License version 2 only, as
7    * published by the Free Software Foundation.
8    *
9    * This code is distributed in the hope that it will be useful, but WITHOUT
10   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12   * version 2 for more details (a copy is included in the LICENSE file that
13   * accompanied this code).
14   *
15   * You should have received a copy of the GNU General Public License version
16   * 2 along with this work; if not, write to the Free Software Foundation,
17   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18   *
19   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20   * or visit www.oracle.com if you need additional information or have any
21   * questions.
22   *
23   */
24  
25  package sun.jvm.hotspot.runtime;
26  
27  import java.util.*;
28  
29  import sun.jvm.hotspot.debugger.*;
30  import sun.jvm.hotspot.oops.*;
31  import sun.jvm.hotspot.types.*;
32  
33  public class BasicLock extends VMObject {
34    static {
35      VM.registerVMInitializedObserver(new Observer() {
36          public void update(Observable o, Object data) {
37            initialize(VM.getVM().getTypeDataBase());
38          }
39        });
40    }
41  
42    private static synchronized void initialize(TypeDataBase db) throws WrongTypeException {
43      Type type  = db.lookupType("BasicLock");
44      displacedHeaderField = type.getCIntegerField("_displaced_header");
45    }
46  
47    private static CIntegerField displacedHeaderField;
48  
49    public BasicLock(Address addr) {
50      super(addr);
51    }
52  
53    public Mark displacedHeader() {
54      return new Mark(addr.addOffsetTo(displacedHeaderField.getOffset()));
55    }
56  }