org.apache.pulsar.common.util.collections.ConcurrentLongLongPairHashMap Maven / Gradle / Ivy
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* regarding copyright ownership. The ASF licenses this file
* to you 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
*
* http://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 org.apache.pulsar.common.util.collections;
import static org.apache.pulsar.shade.com.google.common.base.Preconditions.checkArgument;
import org.apache.pulsar.shade.com.google.common.collect.Lists;
import org.apache.pulsar.shade.com.google.common.collect.Maps;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.concurrent.atomic.AtomicIntegerFieldUpdater;
import java.util.concurrent.locks.StampedLock;
/**
* Concurrent hash map where both keys and values are composed of pairs of longs.
*
* (long,long) --> (long,long)
*
*
Provides similar methods as a {@code ConcurrentMap} but since it's an open hash map with linear probing,
* no node allocations are required to store the keys and values, and no boxing is required.
*
* Keys MUST be >= 0.
*/
public class ConcurrentLongLongPairHashMap {
private static final long EmptyKey = -1L;
private static final long DeletedKey = -2L;
private static final long ValueNotFound = -1L;
private static final int DefaultExpectedItems = 256;
private static final int DefaultConcurrencyLevel = 16;
private static final float DefaultMapFillFactor = 0.66f;
private static final float DefaultMapIdleFactor = 0.15f;
private static final float DefaultExpandFactor = 2;
private static final float DefaultShrinkFactor = 2;
private static final boolean DefaultAutoShrink = false;
private final Section[] sections;
public static Builder newBuilder() {
return new Builder();
}
/**
* Builder of ConcurrentLongLongPairHashMap.
*/
public static class Builder {
int expectedItems = DefaultExpectedItems;
int concurrencyLevel = DefaultConcurrencyLevel;
float mapFillFactor = DefaultMapFillFactor;
float mapIdleFactor = DefaultMapIdleFactor;
float expandFactor = DefaultExpandFactor;
float shrinkFactor = DefaultShrinkFactor;
boolean autoShrink = DefaultAutoShrink;
public Builder expectedItems(int expectedItems) {
this.expectedItems = expectedItems;
return this;
}
public Builder concurrencyLevel(int concurrencyLevel) {
this.concurrencyLevel = concurrencyLevel;
return this;
}
public Builder mapFillFactor(float mapFillFactor) {
this.mapFillFactor = mapFillFactor;
return this;
}
public Builder mapIdleFactor(float mapIdleFactor) {
this.mapIdleFactor = mapIdleFactor;
return this;
}
public Builder expandFactor(float expandFactor) {
this.expandFactor = expandFactor;
return this;
}
public Builder shrinkFactor(float shrinkFactor) {
this.shrinkFactor = shrinkFactor;
return this;
}
public Builder autoShrink(boolean autoShrink) {
this.autoShrink = autoShrink;
return this;
}
public ConcurrentLongLongPairHashMap build() {
return new ConcurrentLongLongPairHashMap(expectedItems, concurrencyLevel,
mapFillFactor, mapIdleFactor, autoShrink, expandFactor, shrinkFactor);
}
}
/**
* A BiConsumer Long pair.
*/
public interface BiConsumerLongPair {
void accept(long key1, long key2, long value1, long value2);
}
/**
* A Long pair function.
*/
public interface LongLongPairFunction {
long apply(long key1, long key2);
}
/**
* A Long pair predicate.
*/
public interface LongLongPairPredicate {
boolean test(long key1, long key2, long value1, long value2);
}
private ConcurrentLongLongPairHashMap(int expectedItems, int concurrencyLevel,
float mapFillFactor, float mapIdleFactor,
boolean autoShrink, float expandFactor, float shrinkFactor) {
checkArgument(expectedItems > 0);
checkArgument(concurrencyLevel > 0);
checkArgument(expectedItems >= concurrencyLevel);
checkArgument(mapFillFactor > 0 && mapFillFactor < 1);
checkArgument(mapIdleFactor > 0 && mapIdleFactor < 1);
checkArgument(mapFillFactor > mapIdleFactor);
checkArgument(expandFactor > 1);
checkArgument(shrinkFactor > 1);
int numSections = concurrencyLevel;
int perSectionExpectedItems = expectedItems / numSections;
int perSectionCapacity = (int) (perSectionExpectedItems / mapFillFactor);
this.sections = new Section[numSections];
for (int i = 0; i < numSections; i++) {
sections[i] = new Section(perSectionCapacity, mapFillFactor, mapIdleFactor,
autoShrink, expandFactor, shrinkFactor);
}
}
public long size() {
long size = 0;
for (Section s : sections) {
size += s.size;
}
return size;
}
public long capacity() {
long capacity = 0;
for (Section s : sections) {
capacity += s.capacity;
}
return capacity;
}
public boolean isEmpty() {
for (Section s : sections) {
if (s.size != 0) {
return false;
}
}
return true;
}
long getUsedBucketCount() {
long usedBucketCount = 0;
for (Section s : sections) {
usedBucketCount += s.usedBuckets;
}
return usedBucketCount;
}
/**
* @param key1
* @param key2
* @return the value or -1 if the key was not present.
*/
public LongPair get(long key1, long key2) {
checkBiggerEqualZero(key1);
long h = hash(key1, key2);
return getSection(h).get(key1, key2, (int) h);
}
public boolean containsKey(long key1, long key2) {
return get(key1, key2) != null;
}
public boolean put(long key1, long key2, long value1, long value2) {
checkBiggerEqualZero(key1);
checkBiggerEqualZero(value1);
long h = hash(key1, key2);
return getSection(h).put(key1, key2, value1, value2, (int) h, false);
}
public boolean putIfAbsent(long key1, long key2, long value1, long value2) {
checkBiggerEqualZero(key1);
checkBiggerEqualZero(value1);
long h = hash(key1, key2);
return getSection(h).put(key1, key2, value1, value2, (int) h, true);
}
/**
* Remove an existing entry if found.
*
* @param key1
* @param key2
* @return the value associated with the key or -1 if key was not present.
*/
public boolean remove(long key1, long key2) {
checkBiggerEqualZero(key1);
long h = hash(key1, key2);
return getSection(h).remove(key1, key2, ValueNotFound, ValueNotFound, (int) h);
}
public boolean remove(long key1, long key2, long value1, long value2) {
checkBiggerEqualZero(key1);
checkBiggerEqualZero(value1);
long h = hash(key1, key2);
return getSection(h).remove(key1, key2, value1, value2, (int) h);
}
private Section getSection(long hash) {
// Use 32 msb out of long to get the section
final int sectionIdx = (int) (hash >>> 32) & (sections.length - 1);
return sections[sectionIdx];
}
public void clear() {
for (Section s : sections) {
s.clear();
}
}
public void forEach(BiConsumerLongPair processor) {
for (Section s : sections) {
s.forEach(processor);
}
}
/**
* @return a new list of all keys (makes a copy).
*/
public List keys() {
List keys = Lists.newArrayListWithExpectedSize((int) size());
forEach((key1, key2, value1, value2) -> keys.add(new LongPair(key1, key2)));
return keys;
}
public List values() {
List values = Lists.newArrayListWithExpectedSize((int) size());
forEach((key1, key2, value1, value2) -> values.add(new LongPair(value1, value2)));
return values;
}
public Map asMap() {
Map map = Maps.newHashMapWithExpectedSize((int) size());
forEach((key1, key2, value1, value2) -> map.put(new LongPair(key1, key2), new LongPair(value1, value2)));
return map;
}
// A section is a portion of the hash map that is covered by a single
@SuppressWarnings("serial")
private static final class Section extends StampedLock {
// Each item take up 4 continuous array space.
private static final int ITEM_SIZE = 4;
// Keys and values are stored interleaved in the table array
private volatile long[] table;
private volatile int capacity;
private final int initCapacity;
private static final AtomicIntegerFieldUpdater SIZE_UPDATER =
AtomicIntegerFieldUpdater.newUpdater(Section.class, "size");
private volatile int size;
private int usedBuckets;
private int resizeThresholdUp;
private int resizeThresholdBelow;
private final float mapFillFactor;
private final float mapIdleFactor;
private final float expandFactor;
private final float shrinkFactor;
private final boolean autoShrink;
Section(int capacity, float mapFillFactor, float mapIdleFactor, boolean autoShrink,
float expandFactor, float shrinkFactor) {
this.capacity = alignToPowerOfTwo(capacity);
this.initCapacity = this.capacity;
this.table = new long[ITEM_SIZE * this.capacity];
this.size = 0;
this.usedBuckets = 0;
this.autoShrink = autoShrink;
this.mapFillFactor = mapFillFactor;
this.mapIdleFactor = mapIdleFactor;
this.expandFactor = expandFactor;
this.shrinkFactor = shrinkFactor;
this.resizeThresholdUp = (int) (this.capacity * mapFillFactor);
this.resizeThresholdBelow = (int) (this.capacity * mapIdleFactor);
Arrays.fill(table, EmptyKey);
}
LongPair get(long key1, long key2, int keyHash) {
long stamp = tryOptimisticRead();
boolean acquiredLock = false;
// add local variable here, so OutOfBound won't happen
long[] table = this.table;
// calculate table.length / 4 as capacity to avoid rehash changing capacity
int bucket = signSafeMod(keyHash, table.length / ITEM_SIZE);
try {
while (true) {
// First try optimistic locking
long storedKey1 = table[bucket];
long storedKey2 = table[bucket + 1];
long storedValue1 = table[bucket + 2];
long storedValue2 = table[bucket + 3];
if (!acquiredLock && validate(stamp)) {
// The values we have read are consistent
if (key1 == storedKey1 && key2 == storedKey2) {
return new LongPair(storedValue1, storedValue2);
} else if (storedKey1 == EmptyKey) {
// Not found
return null;
}
} else {
// Fallback to acquiring read lock
if (!acquiredLock) {
stamp = readLock();
acquiredLock = true;
// update local variable
table = this.table;
bucket = signSafeMod(keyHash, table.length / ITEM_SIZE);
storedKey1 = table[bucket];
storedKey2 = table[bucket + 1];
storedValue1 = table[bucket + 2];
storedValue2 = table[bucket + 3];
}
if (key1 == storedKey1 && key2 == storedKey2) {
return new LongPair(storedValue1, storedValue2);
} else if (storedKey1 == EmptyKey) {
// Not found
return null;
}
}
bucket = (bucket + ITEM_SIZE) & (table.length - 1);
}
} finally {
if (acquiredLock) {
unlockRead(stamp);
}
}
}
boolean put(long key1, long key2, long value1, long value2, int keyHash, boolean onlyIfAbsent) {
long stamp = writeLock();
int bucket = signSafeMod(keyHash, capacity);
// Remember where we find the first available spot
int firstDeletedKey = -1;
try {
while (true) {
long storedKey1 = table[bucket];
long storedKey2 = table[bucket + 1];
if (key1 == storedKey1 && key2 == storedKey2) {
if (!onlyIfAbsent) {
// Over written an old value for same key
table[bucket + 2] = value1;
table[bucket + 3] = value2;
return true;
} else {
return false;
}
} else if (storedKey1 == EmptyKey) {
// Found an empty bucket. This means the key is not in the map. If we've already seen a deleted
// key, we should write at that position
if (firstDeletedKey != -1) {
bucket = firstDeletedKey;
} else {
++usedBuckets;
}
table[bucket] = key1;
table[bucket + 1] = key2;
table[bucket + 2] = value1;
table[bucket + 3] = value2;
SIZE_UPDATER.incrementAndGet(this);
return true;
} else if (storedKey1 == DeletedKey) {
// The bucket contained a different deleted key
if (firstDeletedKey == -1) {
firstDeletedKey = bucket;
}
}
bucket = (bucket + ITEM_SIZE) & (table.length - 1);
}
} finally {
if (usedBuckets > resizeThresholdUp) {
try {
// Expand the hashmap
int newCapacity = alignToPowerOfTwo((int) (capacity * expandFactor));
rehash(newCapacity);
} finally {
unlockWrite(stamp);
}
} else {
unlockWrite(stamp);
}
}
}
private boolean remove(long key1, long key2, long value1, long value2, int keyHash) {
long stamp = writeLock();
int bucket = signSafeMod(keyHash, capacity);
try {
while (true) {
long storedKey1 = table[bucket];
long storedKey2 = table[bucket + 1];
long storedValue1 = table[bucket + 2];
long storedValue2 = table[bucket + 3];
if (key1 == storedKey1 && key2 == storedKey2) {
if (value1 == ValueNotFound || (value1 == storedValue1 && value2 == storedValue2)) {
SIZE_UPDATER.decrementAndGet(this);
cleanBucket(bucket);
return true;
} else {
return false;
}
} else if (storedKey1 == EmptyKey) {
// Key wasn't found
return false;
}
bucket = (bucket + ITEM_SIZE) & (table.length - 1);
}
} finally {
if (autoShrink && size < resizeThresholdBelow) {
try {
// Shrinking must at least ensure initCapacity,
// so as to avoid frequent shrinking and expansion near initCapacity,
// frequent shrinking and expansion,
// additionally opened arrays will consume more memory and affect GC
int newCapacity = Math.max(alignToPowerOfTwo((int) (capacity / shrinkFactor)), initCapacity);
int newResizeThresholdUp = (int) (newCapacity * mapFillFactor);
if (newCapacity < capacity && newResizeThresholdUp > size) {
// shrink the hashmap
rehash(newCapacity);
}
} finally {
unlockWrite(stamp);
}
} else {
unlockWrite(stamp);
}
}
}
private void cleanBucket(int bucket) {
int nextInArray = (bucket + ITEM_SIZE) & (table.length - 1);
if (table[nextInArray] == EmptyKey) {
table[bucket] = EmptyKey;
table[bucket + 1] = EmptyKey;
table[bucket + 2] = ValueNotFound;
table[bucket + 3] = ValueNotFound;
--usedBuckets;
// Cleanup all the buckets that were in `DeletedKey` state, so that we can reduce unnecessary expansions
bucket = (bucket - ITEM_SIZE) & (table.length - 1);
while (table[bucket] == DeletedKey) {
table[bucket] = EmptyKey;
table[bucket + 1] = EmptyKey;
table[bucket + 2] = ValueNotFound;
table[bucket + 3] = ValueNotFound;
--usedBuckets;
bucket = (bucket - ITEM_SIZE) & (table.length - 1);
}
} else {
table[bucket] = DeletedKey;
table[bucket + 1] = DeletedKey;
table[bucket + 2] = ValueNotFound;
table[bucket + 3] = ValueNotFound;
}
}
void clear() {
long stamp = writeLock();
try {
if (autoShrink && capacity > initCapacity) {
shrinkToInitCapacity();
} else {
Arrays.fill(table, EmptyKey);
this.size = 0;
this.usedBuckets = 0;
}
} finally {
unlockWrite(stamp);
}
}
public void forEach(BiConsumerLongPair processor) {
long stamp = tryOptimisticRead();
long[] table = this.table;
boolean acquiredReadLock = false;
try {
// Validate no rehashing
if (!validate(stamp)) {
// Fallback to read lock
stamp = readLock();
acquiredReadLock = true;
table = this.table;
}
// Go through all the buckets for this section
for (int bucket = 0; bucket < table.length; bucket += ITEM_SIZE) {
long storedKey1 = table[bucket];
long storedKey2 = table[bucket + 1];
long storedValue1 = table[bucket + 2];
long storedValue2 = table[bucket + 3];
if (!acquiredReadLock && !validate(stamp)) {
// Fallback to acquiring read lock
stamp = readLock();
acquiredReadLock = true;
storedKey1 = table[bucket];
storedKey2 = table[bucket + 1];
storedValue1 = table[bucket + 2];
storedValue2 = table[bucket + 3];
}
if (storedKey1 != DeletedKey && storedKey1 != EmptyKey) {
processor.accept(storedKey1, storedKey2, storedValue1, storedValue2);
}
}
} finally {
if (acquiredReadLock) {
unlockRead(stamp);
}
}
}
private void rehash(int newCapacity) {
long[] newTable = new long[ITEM_SIZE * newCapacity];
Arrays.fill(newTable, EmptyKey);
// Re-hash table
for (int i = 0; i < table.length; i += ITEM_SIZE) {
long storedKey1 = table[i];
long storedKey2 = table[i + 1];
long storedValue1 = table[i + 2];
long storedValue2 = table[i + 3];
if (storedKey1 != EmptyKey && storedKey1 != DeletedKey) {
insertKeyValueNoLock(newTable, newCapacity, storedKey1, storedKey2, storedValue1, storedValue2);
}
}
table = newTable;
usedBuckets = size;
// Capacity needs to be updated after the values, so that we won't see
// a capacity value bigger than the actual array size
capacity = newCapacity;
resizeThresholdUp = (int) (capacity * mapFillFactor);
resizeThresholdBelow = (int) (capacity * mapIdleFactor);
}
private void shrinkToInitCapacity() {
long[] newTable = new long[ITEM_SIZE * initCapacity];
Arrays.fill(newTable, EmptyKey);
table = newTable;
size = 0;
usedBuckets = 0;
// Capacity needs to be updated after the values, so that we won't see
// a capacity value bigger than the actual array size
capacity = initCapacity;
resizeThresholdUp = (int) (capacity * mapFillFactor);
resizeThresholdBelow = (int) (capacity * mapIdleFactor);
}
private static void insertKeyValueNoLock(long[] table, int capacity, long key1, long key2, long value1,
long value2) {
int bucket = signSafeMod(hash(key1, key2), capacity);
while (true) {
long storedKey1 = table[bucket];
if (storedKey1 == EmptyKey) {
// The bucket is empty, so we can use it
table[bucket] = key1;
table[bucket + 1] = key2;
table[bucket + 2] = value1;
table[bucket + 3] = value2;
return;
}
bucket = (bucket + ITEM_SIZE) & (table.length - 1);
}
}
}
private static final long HashMixer = 0xc6a4a7935bd1e995L;
private static final int R = 47;
static final long hash(long key1, long key2) {
long hash = key1 * HashMixer;
hash ^= hash >>> R;
hash *= HashMixer;
hash += 31 + (key2 * HashMixer);
hash ^= hash >>> R;
hash *= HashMixer;
return hash;
}
static final int signSafeMod(long n, int max) {
// as the ITEM_SIZE of Section is 4, so the index is the multiple of 4
// that is to left shift 2 bits
return (int) (n & (max - 1)) << 2;
}
private static int alignToPowerOfTwo(int n) {
return (int) Math.pow(2, 32 - Integer.numberOfLeadingZeros(n - 1));
}
private static void checkBiggerEqualZero(long n) {
if (n < 0L) {
throw new IllegalArgumentException("Keys and values must be >= 0");
}
}
/**
* A pair of long values.
*/
public static class LongPair implements Comparable {
public final long first;
public final long second;
public LongPair(long first, long second) {
this.first = first;
this.second = second;
}
@Override
public boolean equals(Object obj) {
if (obj instanceof LongPair) {
LongPair other = (LongPair) obj;
return first == other.first && second == other.second;
}
return false;
}
@Override
public int hashCode() {
return (int) hash(first, second);
}
@Override
public int compareTo(LongPair o) {
if (first != o.first) {
return Long.compare(first, o.first);
} else {
return Long.compare(second, o.second);
}
}
}
}