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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* 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).
*
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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 PropertyMap
s with the PropertyMap.sharedProtoMap
field set to the expected shared prototype map. When an instance of this class is evolved because a property is added, removed, or modified in an object using it, the 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is invoked to signal to all callsites and inheriting objects that the assumption of a single shared prototype map is no longer valid.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.
/**
* 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* objects that the assumption of a single shared prototype map is no longer valid.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 map
. Params: - map – property map to copy
/**
* 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.
/**
* 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;
}
}
}