1 /*
   2  * Copyright (c) 2003, 2012, 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.memory;
  26 
  27 import java.util.*;
  28 import sun.jvm.hotspot.classfile.ClassLoaderData;
  29 import sun.jvm.hotspot.debugger.*;
  30 import sun.jvm.hotspot.oops.*;
  31 import sun.jvm.hotspot.types.*;
  32 import sun.jvm.hotspot.runtime.*;
  33 import sun.jvm.hotspot.utilities.*;
  34 
  35 public class PlaceholderEntry extends sun.jvm.hotspot.utilities.HashtableEntry {
  36   static {
  37     VM.registerVMInitializedObserver(new Observer() {
  38         public void update(Observable o, Object data) {
  39           initialize(VM.getVM().getTypeDataBase());
  40         }
  41       });
  42   }
  43 
  44   private static synchronized void initialize(TypeDataBase db) {
  45     Type type = db.lookupType("PlaceholderEntry");
  46     loaderDataField = type.getAddressField("_loader_data");
  47   }
  48 
  49   // Field
  50   private static AddressField loaderDataField;
  51 
  52   // Accessor
  53   public Oop loader() {
  54     return loaderData().getClassLoader();
  55   }
  56 
  57   public ClassLoaderData loaderData() {
  58     return ClassLoaderData.instantiateWrapperFor(loaderDataField.getValue(addr));
  59   }
  60 
  61   public PlaceholderEntry(Address addr) {
  62     super(addr);
  63   }
  64 
  65   public Symbol klass() {
  66     return Symbol.create(literalValue());
  67   }
  68 
  69   /* covariant return type :-(
  70   public PlaceholderEntry next() {
  71     return (PlaceholderEntry) super.next();
  72   }
  73   For now, let the caller cast it ..
  74   */
  75 }