| /* |
| * Copyright (c) 2015, 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. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * 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 jdk.nashorn.internal.runtime; |
| |
| import java.lang.invoke.SwitchPoint; |
| |
| /** |
| * This class represents a property map that can be shared among multiple prototype objects, allowing all inheriting |
| * top-level objects to also share one property map. This class is only used for prototype objects, the |
| * top-level objects use ordinary {@link PropertyMap}s with the {@link PropertyMap#sharedProtoMap} field |
| * set to the expected shared prototype map. |
| * |
| * <p>When an instance of this class is evolved because a property is added, removed, or modified in an object |
| * using it, the {@link #invalidateSwitchPoint()} method is invoked to signal to all callsites and inheriting |
| * objects that the assumption of a single shared prototype map is no longer valid. The property map resulting |
| * from the modification will no longer be an instance of this class.</p> |
| */ |
| public final class SharedPropertyMap extends PropertyMap { |
| |
| private SwitchPoint switchPoint; |
| |
| private static final long serialVersionUID = 2166297719721778876L; |
| |
| /** |
| * Create a new shared property map from the given {@code map}. |
| * @param map property map to copy |
| */ |
| public SharedPropertyMap(final PropertyMap map) { |
| super(map); |
| this.switchPoint = new SwitchPoint(); |
| } |
| |
| @Override |
| public void propertyAdded(final Property property, final boolean isSelf) { |
| if (isSelf) { |
| invalidateSwitchPoint(); |
| } |
| super.propertyAdded(property, isSelf); |
| } |
| |
| @Override |
| public void propertyDeleted(final Property property, final boolean isSelf) { |
| if (isSelf) { |
| invalidateSwitchPoint(); |
| } |
| super.propertyDeleted(property, isSelf); |
| } |
| |
| @Override |
| public void propertyModified(final Property oldProperty, final Property newProperty, final boolean isSelf) { |
| if (isSelf) { |
| invalidateSwitchPoint(); |
| } |
| super.propertyModified(oldProperty, newProperty, isSelf); |
| } |
| |
| @Override |
| synchronized boolean isValidSharedProtoMap() { |
| return switchPoint != null; |
| } |
| |
| @Override |
| synchronized SwitchPoint getSharedProtoSwitchPoint() { |
| return switchPoint; |
| } |
| |
| /** |
| * Invalidate the shared prototype switch point if this is a shared prototype map. |
| */ |
| synchronized void invalidateSwitchPoint() { |
| if (switchPoint != null) { |
| assert !switchPoint.hasBeenInvalidated(); |
| SwitchPoint.invalidateAll(new SwitchPoint[]{ switchPoint }); |
| switchPoint = null; |
| } |
| } |
| } |