Java example source code file (PlaceholderTable.java)

This example Java source code file (PlaceholderTable.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

class, fieldtype, klass, objectheap, placeholderentry, placeholdertable, symbol, twooophashtable

The PlaceholderTable.java Java example source code

/*
 * Copyright (c) 2003, 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
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 *
 */

package sun.jvm.hotspot.memory;

import sun.jvm.hotspot.debugger.*;
import sun.jvm.hotspot.oops.*;
import sun.jvm.hotspot.runtime.*;
import sun.jvm.hotspot.utilities.*;

public class PlaceholderTable extends TwoOopHashtable {
  public PlaceholderTable(Address addr) {
    super(addr);
  }

  // this is overriden here so that Hashtable.bucket will return
  // object of PlacholderEntry.class
  protected Class getHashtableEntryClass() {
    return PlaceholderEntry.class;
  }

  /** All array classes of primitive type, and their class loaders */
  public void primArrayClassesDo(SystemDictionary.ClassAndLoaderVisitor v) {
    ObjectHeap heap = VM.getVM().getObjectHeap();
    int tblSize = tableSize();
    for (int index = 0; index < tblSize; index++) {
      for (PlaceholderEntry probe = (PlaceholderEntry) bucket(index); probe != null;
                                          probe = (PlaceholderEntry) probe.next()) {
        Symbol sym = probe.klass();
        // array of primitive arrays are stored in system dictionary as placeholders
        FieldType ft = new FieldType(sym);
        if (ft.isArray()) {
          FieldType.ArrayInfo info = ft.getArrayInfo();
          if (info.elementBasicType() != BasicType.getTObject()) {
            Klass arrayKlass = heap.typeArrayKlassObj(info.elementBasicType());
            arrayKlass = arrayKlass.arrayKlassOrNull(info.dimension());
            v.visit(arrayKlass, probe.loader());
          }
        }
      }
    }
  }
}