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Easy Redis Java client and Real-Time Data Platform. Valkey compatible. Sync/Async/RxJava3/Reactive API. Client side caching. Over 50 Redis based Java objects and services: JCache API, Apache Tomcat, Hibernate, Spring, Set, Multimap, SortedSet, Map, List, Queue, Deque, Semaphore, Lock, AtomicLong, Map Reduce, Bloom filter, Scheduler, RPC
/*
* Copyright (c) 2016-2022 VMware Inc. or its affiliates, All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package reactor.util.concurrent;
import java.util.Collection;
import java.util.Iterator;
import java.util.Objects;
import java.util.Queue;
import java.util.concurrent.atomic.AtomicLongFieldUpdater;
import java.util.concurrent.atomic.AtomicReferenceArray;
import reactor.util.annotation.Nullable;
/**
* A bounded, array backed, single-producer single-consumer queue.
*
* This implementation is based on JCTools' SPSC algorithms:
* SpscArrayQueue
* and SpscAtomicArrayQueue
* of which the {@code SpscAtomicArrayQueue} was contributed by one of the authors of this library. The notable difference
* is that this class inlines the AtomicReferenceArray directly and there is no lookahead cache involved;
* item padding has a toll on short lived or bursty uses and lookahead doesn't really matter with small queues.
*
* @param the value type
*/
final class SpscArrayQueue extends SpscArrayQueueP3 implements Queue {
/** */
private static final long serialVersionUID = 494623116936946976L;
SpscArrayQueue(int capacity) {
super(Queues.ceilingNextPowerOfTwo(capacity));
}
@Override
public boolean offer(T e) {
Objects.requireNonNull(e, "e");
long pi = producerIndex;
int offset = (int)pi & mask;
if (get(offset) != null) {
return false;
}
lazySet(offset, e);
PRODUCER_INDEX.lazySet(this, pi + 1);
return true;
}
@Override
@Nullable
public T poll() {
long ci = consumerIndex;
int offset = (int)ci & mask;
T v = get(offset);
if (v != null) {
lazySet(offset, null);
CONSUMER_INDEX.lazySet(this, ci + 1);
}
return v;
}
@Override
@Nullable
public T peek() {
int offset = (int)consumerIndex & mask;
return get(offset);
}
@Override
public boolean isEmpty() {
return producerIndex == consumerIndex;
}
@Override
public void clear() {
while (poll() != null && !isEmpty());
}
@Override
public int size() {
long ci = consumerIndex;
for (;;) {
long pi = producerIndex;
long ci2 = consumerIndex;
if (ci == ci2) {
return (int)(pi - ci);
}
ci = ci2;
}
}
@Override
public boolean contains(Object o) {
throw new UnsupportedOperationException();
}
@Override
public Iterator iterator() {
throw new UnsupportedOperationException();
}
@Override
public Object[] toArray() {
throw new UnsupportedOperationException();
}
@Override
public R[] toArray(R[] a) {
throw new UnsupportedOperationException();
}
@Override
public boolean remove(Object o) {
throw new UnsupportedOperationException();
}
@Override
public boolean containsAll(Collection> c) {
throw new UnsupportedOperationException();
}
@Override
public boolean addAll(Collection extends T> c) {
throw new UnsupportedOperationException();
}
@Override
public boolean removeAll(Collection> c) {
throw new UnsupportedOperationException();
}
@Override
public boolean retainAll(Collection> c) {
throw new UnsupportedOperationException();
}
@Override
public boolean add(T e) {
throw new UnsupportedOperationException();
}
@Override
public T remove() {
throw new UnsupportedOperationException();
}
@Override
public T element() {
throw new UnsupportedOperationException();
}
}
class SpscArrayQueueCold extends AtomicReferenceArray {
/** */
private static final long serialVersionUID = 8491797459632447132L;
final int mask;
public SpscArrayQueueCold(int length) {
super(length);
mask = length - 1;
}
}
@SuppressWarnings("unused")
class SpscArrayQueueP1 extends SpscArrayQueueCold {
/** */
private static final long serialVersionUID = -4461305682174876914L;
byte pad000,pad001,pad002,pad003,pad004,pad005,pad006,pad007;// 8b
byte pad010,pad011,pad012,pad013,pad014,pad015,pad016,pad017;// 16b
byte pad020,pad021,pad022,pad023,pad024,pad025,pad026,pad027;// 24b
byte pad030,pad031,pad032,pad033,pad034,pad035,pad036,pad037;// 32b
byte pad040,pad041,pad042,pad043,pad044,pad045,pad046,pad047;// 40b
byte pad050,pad051,pad052,pad053,pad054,pad055,pad056,pad057;// 48b
byte pad060,pad061,pad062,pad063,pad064,pad065,pad066,pad067;// 56b
byte pad070,pad071,pad072,pad073,pad074,pad075,pad076,pad077;// 64b
byte pad100,pad101,pad102,pad103,pad104,pad105,pad106,pad107;// 72b
byte pad110,pad111,pad112,pad113,pad114,pad115,pad116,pad117;// 80b
byte pad120,pad121,pad122,pad123,pad124,pad125,pad126,pad127;// 88b
byte pad130,pad131,pad132,pad133,pad134,pad135,pad136,pad137;// 96b
byte pad140,pad141,pad142,pad143,pad144,pad145,pad146,pad147;//104b
byte pad150,pad151,pad152,pad153,pad154,pad155,pad156,pad157;//112b
byte pad160,pad161,pad162,pad163,pad164,pad165,pad166,pad167;//120b
byte pad170,pad171,pad172,pad173,pad174,pad175,pad176,pad177;//128b
byte pad200,pad201,pad202,pad203; //132b
SpscArrayQueueP1(int length) {
super(length);
}
}
class SpscArrayQueueProducer extends SpscArrayQueueP1 {
/** */
private static final long serialVersionUID = 1657408315616277653L;
SpscArrayQueueProducer(int length) {
super(length);
}
volatile long producerIndex;
@SuppressWarnings("rawtypes")
static final AtomicLongFieldUpdater PRODUCER_INDEX =
AtomicLongFieldUpdater.newUpdater(SpscArrayQueueProducer.class, "producerIndex");
}
@SuppressWarnings("unused")
class SpscArrayQueueP2 extends SpscArrayQueueProducer {
/** */
private static final long serialVersionUID = -5400235061461013116L;
byte pad000,pad001,pad002,pad003,pad004,pad005,pad006,pad007;// 8b
byte pad010,pad011,pad012,pad013,pad014,pad015,pad016,pad017;// 16b
byte pad020,pad021,pad022,pad023,pad024,pad025,pad026,pad027;// 24b
byte pad030,pad031,pad032,pad033,pad034,pad035,pad036,pad037;// 32b
byte pad040,pad041,pad042,pad043,pad044,pad045,pad046,pad047;// 40b
byte pad050,pad051,pad052,pad053,pad054,pad055,pad056,pad057;// 48b
byte pad060,pad061,pad062,pad063,pad064,pad065,pad066,pad067;// 56b
byte pad070,pad071,pad072,pad073,pad074,pad075,pad076,pad077;// 64b
byte pad100,pad101,pad102,pad103,pad104,pad105,pad106,pad107;// 72b
byte pad110,pad111,pad112,pad113,pad114,pad115,pad116,pad117;// 80b
byte pad120,pad121,pad122,pad123,pad124,pad125,pad126,pad127;// 88b
byte pad130,pad131,pad132,pad133,pad134,pad135,pad136,pad137;// 96b
byte pad140,pad141,pad142,pad143,pad144,pad145,pad146,pad147;//104b
byte pad150,pad151,pad152,pad153,pad154,pad155,pad156,pad157;//112b
byte pad160,pad161,pad162,pad163,pad164,pad165,pad166,pad167;//120b
byte pad170,pad171,pad172,pad173,pad174,pad175,pad176,pad177;//128b
SpscArrayQueueP2(int length) {
super(length);
}
}
class SpscArrayQueueConsumer extends SpscArrayQueueP2 {
/** */
private static final long serialVersionUID = 4075549732218321659L;
SpscArrayQueueConsumer(int length) {
super(length);
}
volatile long consumerIndex;
@SuppressWarnings("rawtypes")
static final AtomicLongFieldUpdater CONSUMER_INDEX =
AtomicLongFieldUpdater.newUpdater(SpscArrayQueueConsumer.class, "consumerIndex");
}
@SuppressWarnings("unused")
class SpscArrayQueueP3 extends SpscArrayQueueConsumer {
/** */
private static final long serialVersionUID = -2684922090021364171L;
byte pad000,pad001,pad002,pad003,pad004,pad005,pad006,pad007;// 8b
byte pad010,pad011,pad012,pad013,pad014,pad015,pad016,pad017;// 16b
byte pad020,pad021,pad022,pad023,pad024,pad025,pad026,pad027;// 24b
byte pad030,pad031,pad032,pad033,pad034,pad035,pad036,pad037;// 32b
byte pad040,pad041,pad042,pad043,pad044,pad045,pad046,pad047;// 40b
byte pad050,pad051,pad052,pad053,pad054,pad055,pad056,pad057;// 48b
byte pad060,pad061,pad062,pad063,pad064,pad065,pad066,pad067;// 56b
byte pad070,pad071,pad072,pad073,pad074,pad075,pad076,pad077;// 64b
byte pad100,pad101,pad102,pad103,pad104,pad105,pad106,pad107;// 72b
byte pad110,pad111,pad112,pad113,pad114,pad115,pad116,pad117;// 80b
byte pad120,pad121,pad122,pad123,pad124,pad125,pad126,pad127;// 88b
byte pad130,pad131,pad132,pad133,pad134,pad135,pad136,pad137;// 96b
byte pad140,pad141,pad142,pad143,pad144,pad145,pad146,pad147;//104b
byte pad150,pad151,pad152,pad153,pad154,pad155,pad156,pad157;//112b
byte pad160,pad161,pad162,pad163,pad164,pad165,pad166,pad167;//120b
byte pad170,pad171,pad172,pad173,pad174,pad175,pad176,pad177;//128b
SpscArrayQueueP3(int length) {
super(length);
}
}
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