KlassArray.java

/*
 * Copyright (c) 2012, 2020, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package sun.jvm.hotspot.utilities;

import sun.jvm.hotspot.debugger.Address;
import sun.jvm.hotspot.oops.Metadata;
import sun.jvm.hotspot.oops.Klass;
import sun.jvm.hotspot.runtime.VM;
import sun.jvm.hotspot.types.Type;
import sun.jvm.hotspot.types.TypeDataBase;
import sun.jvm.hotspot.types.WrongTypeException;
import sun.jvm.hotspot.utilities.Observable;
import sun.jvm.hotspot.utilities.Observer;

public class KlassArray extends GenericArray {
  static {
    VM.registerVMInitializedObserver(new Observer() {
      public void update(Observable o, Object data) {
        initialize(VM.getVM().getTypeDataBase());
      }
    });
  }

  private static synchronized void initialize(TypeDataBase db) throws WrongTypeException {
    elemType = db.lookupType("Klass*");

    Type type = db.lookupType("Array<Klass*>");
    dataFieldOffset = type.getAddressField("_data").getOffset();
  }

  private static long dataFieldOffset;
  protected static Type elemType;

  public KlassArray(Address addr) {
    super(addr, dataFieldOffset);
  }

  public Klass getAt(int i) {
    return (Klass) Metadata.instantiateWrapperFor(getAddressAt(i));
  }

  public Type getElemType() {
    return elemType;
  }
}