merlimat commented on a change in pull request #3818: [pulsar-common] add open Concurrent LongPair RangeSet URL: https://github.com/apache/pulsar/pull/3818#discussion_r285224145
########## File path: pulsar-common/src/main/java/org/apache/pulsar/common/util/collections/ConcurrentOpenLongPairRangeSet.java ########## @@ -0,0 +1,474 @@ +/** + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * 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 com.google.common.base.Preconditions.checkNotNull; + +import java.util.ArrayList; +import java.util.BitSet; +import java.util.List; +import java.util.Map.Entry; +import java.util.NavigableMap; +import java.util.concurrent.ConcurrentSkipListMap; +import java.util.concurrent.atomic.AtomicBoolean; +import java.util.concurrent.atomic.AtomicInteger; +import java.util.concurrent.locks.StampedLock; + +import org.apache.pulsar.common.util.collections.LongPairRangeSet.LongPairConsumer; +import org.apache.pulsar.common.util.collections.LongPairRangeSet.RangeProcessor; + +import com.google.common.collect.BoundType; +import com.google.common.collect.Range; + +/** + * A Concurrent set comprising zero or more ranges of type {@link LongPair}. This can be alternative of + * {@link com.google.common.collect.RangeSet} and can be used if {@code range} type is {@link LongPair} </br> + * + * <pre> + * + * Usage: + * a. This can be used if one doesn't want to create object for every new inserted {@code range} + * b. It creates {@link BitSet} for every unique first-key of the range. + * So, this rangeSet is not suitable for large number of unique keys. + * </pre> + * + * + */ +public class ConcurrentOpenLongPairRangeSet<T extends Comparable<T>> implements LongPairRangeSet<T> { + + protected final NavigableMap<Long, BitSet> rangeBitSetMap = new ConcurrentSkipListMap<>(); + private boolean threadSafe = true; + private final int bitSetSize; + private final LongPairConsumer<T> consumer; + + // caching place-holder for cpu-optimization to avoid calculating ranges again + private volatile int cachedSize = 0; + private volatile String cachedToString = "[]"; + private volatile boolean updatedAfterCached = true; + + public ConcurrentOpenLongPairRangeSet(LongPairConsumer<T> consumer) { + this(1024, true, consumer); + } + + public ConcurrentOpenLongPairRangeSet(int size, LongPairConsumer<T> consumer) { + this(size, true, consumer); + } + + public ConcurrentOpenLongPairRangeSet(int size, boolean threadSafe, LongPairConsumer<T> consumer) { + this.threadSafe = threadSafe; + this.bitSetSize = size; + this.consumer = consumer; + } + + class ConcurrentBitSet extends BitSet { + private static final long serialVersionUID = 1L; + private final StampedLock rwLock = new StampedLock(); + + /** + * Creates a bit set whose initial size is large enough to explicitly represent bits with indices in the range + * {@code 0} through {@code nbits-1}. All bits are initially {@code false}. + * + * @param nbits + * the initial size of the bit set + * @throws NegativeArraySizeException + * if the specified initial size is negative + */ + public ConcurrentBitSet(int nbits) { + super(nbits); + } + + @Override + public boolean get(int bitIndex) { + return super.get(bitIndex); + } + + @Override + public void set(int bitIndex) { + long stamp = rwLock.writeLock(); + try { + super.set(bitIndex); + } finally { + rwLock.unlockWrite(stamp); + } + } + + @Override + public void set(int fromIndex, int toIndex) { + long stamp = rwLock.writeLock(); + try { + super.set(fromIndex, toIndex); + } finally { + rwLock.unlockWrite(stamp); + } + } + + @Override + public int nextSetBit(int fromIndex) { + long stamp = rwLock.readLock(); + try { + return super.nextSetBit(fromIndex); + } finally { + rwLock.unlockRead(stamp); + } + } + + @Override + public int nextClearBit(int fromIndex) { + long stamp = rwLock.readLock(); + try { + return super.nextClearBit(fromIndex); + } finally { + rwLock.unlockRead(stamp); + } Review comment: Using the stamped lock, allow for less expensive read path. eg: ```java long stamp = rwLock.tryOptimisticRead(); int bit = super.nextClearBit(fromIndex); if (!rwLock.validate(stamp)) { stamp = rwLock.readLock(); try { bit = super.nextClearBit(fromIndex); } finally { rwLock.unlockRead(stamp); } } return bit; ``` The idea is to only fallback to read lock when there's a write happening at the same time, otherwise it's just 2 volatile reads. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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