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/*
* Copyright (c) 2008, 2020 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v. 2.0, which is available at
* http://www.eclipse.org/legal/epl-2.0.
*
* This Source Code may also be made available under the following Secondary
* Licenses when the conditions for such availability set forth in the
* Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
* version 2 with the GNU Classpath Exception, which is available at
* https://www.gnu.org/software/classpath/license.html.
*
* SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
*/
package org.glassfish.grizzly.attributes;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import java.util.function.Supplier;
/**
* A non thread-safe {@link AttributeHolder} implementation.
*
* @author Alexey Stashok
*/
final class UnsafeAttributeHolder implements AttributeHolder {
// the associated AttributeBuilder
final DefaultAttributeBuilder attributeBuilder;
// the associated IndexedAttributeAccessorImpl
final IndexedAttributeAccessorImpl indexedAttributeAccessor;
// list of "optimistic" holders to be used before going to a slower Map storage
private final Holder h1 = new Holder();
private final Holder h2 = new Holder();
private final Holder h3 = new Holder();
private final Holder h4 = new Holder();
// the Map storage
private Map valueMap;
// true, if at least one element has been set
private boolean isSet;
UnsafeAttributeHolder(final DefaultAttributeBuilder attributeBuilder) {
this.attributeBuilder = attributeBuilder;
indexedAttributeAccessor = new IndexedAttributeAccessorImpl();
}
@Override
public Object getAttribute(final String name) {
return getAttribute(name, null);
}
@Override
public Object getAttribute(final String name, final Supplier initializer) {
if (!isSet && initializer == null) {
return null;
}
final Attribute attribute = attributeBuilder.getAttributeByName(name);
if (attribute != null) {
return indexedAttributeAccessor.getAttribute(attribute, initializer);
}
return initializer != null ? initializer.get() : null;
}
@Override
public void setAttribute(final String name, final Object value) {
Attribute attribute = attributeBuilder.getAttributeByName(name);
if (attribute == null) {
attribute = attributeBuilder.createAttribute(name);
}
indexedAttributeAccessor.setAttribute(attribute, value);
}
@Override
public Object removeAttribute(final String name) {
if (!isSet) {
return null;
}
final Attribute attribute = attributeBuilder.getAttributeByName(name);
if (attribute != null) {
return indexedAttributeAccessor.removeAttribute(attribute);
}
return null;
}
@Override
public Set getAttributeNames() {
if (!isSet) {
return null;
}
final Set tmpSet = new HashSet<>(4);
if (h1.isSet && h1.value != null) {
tmpSet.add(attributeBuilder.getAttributeByIndex(h1.idx).name());
}
if (h2.isSet && h2.value != null) {
tmpSet.add(attributeBuilder.getAttributeByIndex(h2.idx).name());
}
if (h3.isSet && h3.value != null) {
tmpSet.add(attributeBuilder.getAttributeByIndex(h3.idx).name());
}
if (h4.isSet && h4.value != null) {
tmpSet.add(attributeBuilder.getAttributeByIndex(h4.idx).name());
}
if (valueMap != null) {
for (Integer idx : valueMap.keySet()) {
tmpSet.add(attributeBuilder.getAttributeByIndex(idx).name());
}
}
return tmpSet;
}
@Override
public void clear() {
if (!isSet) {
return;
}
isSet = false;
h1.clear();
h2.clear();
h3.clear();
h4.clear();
valueMap = null;
}
@Override
public void recycle() {
clear();
}
@Override
public AttributeBuilder getAttributeBuilder() {
return attributeBuilder;
}
@Override
public IndexedAttributeAccessor getIndexedAttributeAccessor() {
return indexedAttributeAccessor;
}
@Override
public void copyFrom(final AttributeHolder srcAttributes) {
if (srcAttributes == null) {
throw new NullPointerException("srcAttributes can't be null");
}
if (srcAttributes instanceof UnsafeAttributeHolder) {
// optimistic case
final UnsafeAttributeHolder srcUnsafe = (UnsafeAttributeHolder) srcAttributes;
if (!srcUnsafe.isSet) {
clear();
return;
}
isSet = true;
h1.copyFrom(srcUnsafe.h1);
h2.copyFrom(srcUnsafe.h2);
h3.copyFrom(srcUnsafe.h3);
h4.copyFrom(srcUnsafe.h4);
if (valueMap != null || srcUnsafe.valueMap != null) {
MapperAccessor.copy(srcUnsafe, this);
}
} else {
// pessimistic case (slow)
clear();
final Set names = srcAttributes.getAttributeNames();
for (String name : names) {
setAttribute(name, srcAttributes.getAttribute(name));
}
}
}
@Override
public void copyTo(final AttributeHolder dstAttributes) {
if (dstAttributes == null) {
throw new NullPointerException("dstAttributes can't be null");
}
if (!isSet) {
dstAttributes.clear();
return;
}
if (dstAttributes instanceof UnsafeAttributeHolder) {
// optimistic case
final UnsafeAttributeHolder dstUnsafe = (UnsafeAttributeHolder) dstAttributes;
dstUnsafe.isSet = true;
dstUnsafe.h1.copyFrom(h1);
dstUnsafe.h2.copyFrom(h2);
dstUnsafe.h3.copyFrom(h3);
dstUnsafe.h4.copyFrom(h4);
if (valueMap != null || dstUnsafe.valueMap != null) {
MapperAccessor.copy(this, dstUnsafe);
}
} else {
// pessimistic case (slow)
dstAttributes.clear();
final Set names = getAttributeNames();
for (String name : names) {
dstAttributes.setAttribute(name, getAttribute(name));
}
}
}
/**
* {@link IndexedAttributeAccessor} implementation.
*/
protected final class IndexedAttributeAccessorImpl implements IndexedAttributeAccessor {
@Override
public Object getAttribute(final int index) {
return getAttribute(index, null);
}
@Override
public Object getAttribute(final int index, final Supplier initializer) {
if (!isSet && initializer == null) {
return null;
}
return getAttribute(attributeBuilder.getAttributeByIndex(index), initializer);
}
@Override
public void setAttribute(final int index, final Object value) {
setAttribute(attributeBuilder.getAttributeByIndex(index), value);
}
@Override
public Object removeAttribute(final int index) {
return removeAttribute(attributeBuilder.getAttributeByIndex(index));
}
private Object getAttribute(final Attribute attribute, final Supplier initializer) {
final int idx = attribute.index();
final Holder h = holderByIdx(idx);
if (h != null) {
if (h.value == null && initializer != null) {
h.value = initializer.get();
}
return h.value;
}
Object value = valueMap != null ? MapperAccessor.getValue(UnsafeAttributeHolder.this, idx) : null;
if (value == null && initializer != null) {
value = initializer.get();
setAttribute(attribute, value);
}
return value;
}
private Object setAttribute(final Attribute attribute, final Object value) {
if (!isSet) {
if (value != null) {
// optimized first value set
isSet = true;
h1.set(attribute.index(), value);
}
return null;
}
isSet = true;
final int idx = attribute.index();
Holder h = holderByIdx(idx);
if (h != null) {
return h.set(idx, value);
}
if (valueMap != null &&
// we could use valueMap.contains(idx), but weak comparison is even better.
// strong equals comparison will be executed inside MapperAccessor.setValue
valueMap.get(idx) != value) {
// we go here only if we're sure the element is already in the map
// and we need to update it
return MapperAccessor.setValue(UnsafeAttributeHolder.this, idx, value);
}
// if the value is null - it means we supposed to remove the attribute.
// but it wasn't found - so we can return
if (value == null) {
return null;
}
// Now we know there is no old value associated with the attribute
// so we can find an empty holder to store the value
h = emptyHolder();
if (h != null) {
h.set(idx, value);
return null;
}
// there's no empty holder
// check if there's a holder caching null value
h = nullHolder();
if (h != null) {
// if yes - override it
h.set(idx, value);
return null;
}
// and finally if there's no other way around - just store the
// value in the map
return MapperAccessor.setValue(UnsafeAttributeHolder.this, idx, value);
}
private Object removeAttribute(final Attribute attribute) {
return setAttribute(attribute, null);
}
private Holder holderByIdx(final int idx) {
if (h1.is(idx)) {
return h1;
}
if (h2.is(idx)) {
return h2;
}
if (h3.is(idx)) {
return h3;
}
if (h4.is(idx)) {
return h4;
}
return null;
}
private Holder emptyHolder() {
if (!h1.isSet) {
return h1;
}
if (!h2.isSet) {
return h2;
}
if (!h3.isSet) {
return h3;
}
if (!h4.isSet) {
return h4;
}
return null;
}
// we call this method, when we're sure all the holders are set
private Holder nullHolder() {
if (h1.value == null) {
return h1;
}
if (h2.value == null) {
return h2;
}
if (h3.value == null) {
return h3;
}
if (h4.value == null) {
return h4;
}
return null;
}
}
private static final class Holder {
int idx;
Object value;
boolean isSet;
Object set(final int idx, final Object value) {
final Object oldValue = this.value;
this.idx = idx;
this.value = value;
isSet = true;
return oldValue;
}
void clear() {
if (isSet) {
idx = -1;
value = null;
isSet = false;
}
}
private boolean is(final int idx) {
return isSet && this.idx == idx;
}
private void copyFrom(final Holder src) {
isSet = src.isSet;
idx = src.idx;
value = src.value;
}
}
private static final class MapperAccessor {
private static Object getValue(final UnsafeAttributeHolder holder, final Integer idx) {
return holder.valueMap.get(idx);
}
private static Object setValue(final UnsafeAttributeHolder holder, final Integer idx, final Object value) {
if (value == null) {
if (holder.valueMap != null) {
return holder.valueMap.remove(idx);
}
return null;
}
if (holder.valueMap == null) {
holder.valueMap = new HashMap<>(4);
}
return holder.valueMap.put(idx, value);
}
private static void copy(final UnsafeAttributeHolder src, final UnsafeAttributeHolder dst) {
if (src.valueMap != null) {
if (dst.valueMap == null) {
dst.valueMap = new HashMap<>(src.valueMap.size());
} else {
dst.valueMap.clear();
}
dst.valueMap.putAll(src.valueMap);
} else {
dst.valueMap = null;
}
}
}
}
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