1 /*
   2  * Copyright (c) 2003, 2011, 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.debugger.*;
  29 import sun.jvm.hotspot.oops.*;
  30 import sun.jvm.hotspot.types.*;
  31 import sun.jvm.hotspot.runtime.*;
  32 import sun.jvm.hotspot.utilities.*;
  33 
  34 public class LoaderConstraintEntry extends sun.jvm.hotspot.utilities.HashtableEntry {
  35   static {
  36     VM.registerVMInitializedObserver(new Observer() {
  37         public void update(Observable o, Object data) {
  38           initialize(VM.getVM().getTypeDataBase());
  39         }
  40       });
  41   }
  42 
  43   private static synchronized void initialize(TypeDataBase db) {
  44     Type type = db.lookupType("LoaderConstraintEntry");
  45     nameField = type.getAddressField("_name");
  46     numLoadersField = type.getCIntegerField("_num_loaders");
  47     maxLoadersField = type.getCIntegerField("_max_loaders");
  48     loadersField = type.getAddressField("_loaders");
  49   }
  50 
  51   // Fields
  52   private static AddressField nameField;
  53   private static CIntegerField numLoadersField;
  54   private static CIntegerField maxLoadersField;
  55   private static AddressField loadersField;
  56 
  57   // Accessors
  58 
  59   public Symbol name() {
  60     return Symbol.create(nameField.getValue(addr));
  61   }
  62 
  63   public int numLoaders() {
  64     return (int) numLoadersField.getValue(addr);
  65   }
  66 
  67   public int maxLoaders() {
  68     return (int) maxLoadersField.getValue(addr);
  69   }
  70 
  71   public Oop initiatingLoader(int i) {
  72     if (Assert.ASSERTS_ENABLED) {
  73       Assert.that(i >= 0 && i < numLoaders(), "invalid index");
  74     }
  75     Address loaders = loadersField.getValue(addr);
  76     OopHandle loader = loaders.addOffsetToAsOopHandle(i * VM.getVM().getOopSize());
  77     return VM.getVM().getObjectHeap().newOop(loader);
  78   }
  79 
  80   public LoaderConstraintEntry(Address addr) {
  81     super(addr);
  82   }
  83 
  84   /* covariant return type :-(
  85   public LoaderConstraintEntry next() {
  86     return (LoaderConstraintEntry) super.next();
  87   }
  88   For now, let the caller cast it ..
  89   */
  90 }