| /* |
| * Copyright (c) 2000, 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 java.util.*; |
| |
| import sun.jvm.hotspot.debugger.*; |
| import sun.jvm.hotspot.runtime.*; |
| import sun.jvm.hotspot.types.*; |
| |
| /** A space that supports compaction operations. This is usually, but |
| not necessarily, a space that is normally contiguous. But, for |
| example, a free-list-based space whose normal collection is a |
| mark-sweep without compaction could still support compaction in |
| full GC's. */ |
| |
| public abstract class CompactibleSpace extends Space { |
| private static AddressField compactionTopField; |
| |
| static { |
| VM.registerVMInitializedObserver(new Observer() { |
| public void update(Observable o, Object data) { |
| initialize(VM.getVM().getTypeDataBase()); |
| } |
| }); |
| } |
| |
| private static synchronized void initialize(TypeDataBase db) { |
| Type type = db.lookupType("CompactibleSpace"); |
| |
| compactionTopField = type.getAddressField("_compaction_top"); |
| } |
| |
| public CompactibleSpace(Address addr) { |
| super(addr); |
| } |
| |
| /** May be used temporarily during a compaction phase. */ |
| public Address compactionTop() { |
| return compactionTopField.getValue(addr); |
| } |
| } |