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.utilities; 26 27 import java.util.*; 28 import sun.jvm.hotspot.debugger.*; 29 import sun.jvm.hotspot.oops.Oop; 30 import sun.jvm.hotspot.oops.ObjectHeap; 31 import sun.jvm.hotspot.types.*; 32 import sun.jvm.hotspot.runtime.*; 33 34 public class BasicHashtableEntry extends VMObject { 35 static { VM.registerVMInitializedObserver(new Observer() { public void update(Observable o, Object data) { initialize(VM.getVM().getTypeDataBase()); } })36 VM.registerVMInitializedObserver(new Observer() { 37 public void update(Observable o, Object data) { 38 initialize(VM.getVM().getTypeDataBase()); 39 } 40 }); 41 } 42 initialize(TypeDataBase db)43 private static synchronized void initialize(TypeDataBase db) { 44 Type type = db.lookupType("BasicHashtableEntry<mtInternal>"); 45 hashField = type.getCIntegerField("_hash"); 46 nextField = type.getAddressField("_next"); 47 } 48 49 // Fields 50 private static CIntegerField hashField; 51 private static AddressField nextField; 52 53 // Accessors hash()54 public long hash() { 55 return hashField.getValue(addr) & 0xFFFFFFFFL; 56 } 57 nextAddressValue()58 private long nextAddressValue() { 59 Debugger dbg = VM.getVM().getDebugger(); 60 Address nextValue = nextField.getValue(addr); 61 return (nextValue != null) ? dbg.getAddressValue(nextValue) : 0L; 62 } 63 isShared()64 public boolean isShared() { 65 return (nextAddressValue() & 1L) != 0; 66 } 67 next()68 public BasicHashtableEntry next() { 69 Address nextValue = nextField.getValue(addr); 70 Address next = (nextValue != null)? nextValue.andWithMask(-2L) : null; 71 // using this.getClass so that return type will be as expected in 72 // subclass context. But, because we can't use covariant return type 73 // caller has to use this next and cast the result to correct type. 74 return (BasicHashtableEntry) VMObjectFactory.newObject(this.getClass(), next); 75 } 76 BasicHashtableEntry(Address addr)77 public BasicHashtableEntry(Address addr) { 78 super(addr); 79 } 80 } 81