1 /*
 2  * Copyright (c) 2000, 2020, 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.oops;
26 
27 import java.io.*;
28 import java.util.*;
29 import sun.jvm.hotspot.debugger.*;
30 import sun.jvm.hotspot.runtime.*;
31 import sun.jvm.hotspot.types.*;
32 import sun.jvm.hotspot.utilities.Observable;
33 import sun.jvm.hotspot.utilities.Observer;
34 
35 // An Instance is an instance of a Java Class
36 
37 public class Instance extends Oop {
38   static {
39     VM.registerVMInitializedObserver(new Observer() {
40         public void update(Observable o, Object data) {
41           initialize(VM.getVM().getTypeDataBase());
42         }
43       });
44   }
45   private static long typeSize;
46 
47   private static synchronized void initialize(TypeDataBase db) throws WrongTypeException {
48     Type type = db.lookupType("instanceOopDesc");
49     typeSize = type.getSize();
50   }
51 
52   Instance(OopHandle handle, ObjectHeap heap) {
53     super(handle, heap);
54   }
55 
56   // Returns header size in bytes.
57   public static long getHeaderSize() {
58     if (VM.getVM().isCompactObjectHeadersEnabled()) {
59       return Oop.getHeaderSize();
60     }
61     if (VM.getVM().isCompressedKlassPointersEnabled()) {
62       return typeSize - VM.getVM().getIntSize();
63     } else {
64       return typeSize;
65     }
66   }
67 
68   public boolean isInstance()          { return true; }
69 
70   public void iterateFields(OopVisitor visitor, boolean doVMFields) {
71     super.iterateFields(visitor, doVMFields);
72     ((InstanceKlass) getKlass()).iterateNonStaticFields(visitor, this);
73   }
74 
75   public void printValueOn(PrintStream tty) {
76     // Special-case strings.
77     // FIXME: would like to do this in more type-safe fashion (need
78     // SystemDictionary analogue)
79     if (getKlass().getName().asString().equals("java/lang/String")) {
80       tty.print("\"" + OopUtilities.stringOopToString(this) + "\"");
81     } else {
82       super.printValueOn(tty);
83     }
84   }
85 }