1 /*
 2  * * Copyright Amazon.com Inc. 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.gc.shenandoah;
26 
27 import sun.jvm.hotspot.utilities.Observable;
28 import sun.jvm.hotspot.utilities.Observer;
29 
30 import sun.jvm.hotspot.debugger.Address;
31 import sun.jvm.hotspot.runtime.VM;
32 import sun.jvm.hotspot.runtime.VMObject;
33 import sun.jvm.hotspot.types.CIntegerField;
34 import sun.jvm.hotspot.types.Type;
35 import sun.jvm.hotspot.types.TypeDataBase;
36 
37 public class ShenandoahGeneration extends VMObject {
38     private static CIntegerField used;
39     static {
40         VM.registerVMInitializedObserver(new Observer() {
41             public void update(Observable o, Object data) {
42                 initialize(VM.getVM().getTypeDataBase());
43             }
44         });
45     }
46 
47     private static synchronized void initialize(TypeDataBase db) {
48         Type type = db.lookupType("ShenandoahGeneration");
49         used = type.getCIntegerField("_used");
50     }
51 
52     public ShenandoahGeneration(Address addr) {
53         super(addr);
54     }
55 
56     public long used() {
57         return used.getValue(addr);
58     }
59 }