org.apache.pulsar.client.impl.customroute.PartialRoundRobinMessageRouterImpl Maven / Gradle / Ivy
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* 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
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* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.pulsar.client.impl.customroute;
import static org.apache.pulsar.client.util.MathUtils.signSafeMod;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.atomic.AtomicIntegerFieldUpdater;
import java.util.stream.Collectors;
import java.util.stream.IntStream;
import org.apache.pulsar.client.api.Message;
import org.apache.pulsar.client.api.MessageRouter;
import org.apache.pulsar.client.api.TopicMetadata;
public class PartialRoundRobinMessageRouterImpl implements MessageRouter {
private final int numPartitionsLimit;
private final List partialList = new CopyOnWriteArrayList<>();
private static final AtomicIntegerFieldUpdater PARTITION_INDEX_UPDATER =
AtomicIntegerFieldUpdater.newUpdater(PartialRoundRobinMessageRouterImpl.class, "partitionIndex");
@SuppressWarnings("unused")
private volatile int partitionIndex = 0;
public PartialRoundRobinMessageRouterImpl(final int numPartitionsLimit) {
if (numPartitionsLimit < 1) {
throw new IllegalArgumentException("numPartitionsLimit should be greater than or equal to 1");
}
this.numPartitionsLimit = numPartitionsLimit;
}
/**
* Choose a partition based on the topic metadata.
* Key hash routing isn't supported.
*
* @param msg message
* @param metadata topic metadata
* @return the partition to route the message.
*/
public int choosePartition(Message msg, TopicMetadata metadata) {
final List newPartialList = new ArrayList<>(getOrCreatePartialList(metadata));
return newPartialList
.get(signSafeMod(PARTITION_INDEX_UPDATER.getAndIncrement(this), newPartialList.size()));
}
private List getOrCreatePartialList(TopicMetadata metadata) {
if (partialList.isEmpty()
|| partialList.size() < numPartitionsLimit && partialList.size() < metadata.numPartitions()) {
synchronized (this) {
if (partialList.isEmpty()) {
partialList.addAll(IntStream.range(0, metadata.numPartitions()).boxed()
.collect(Collectors.collectingAndThen(Collectors.toList(), list -> {
Collections.shuffle(list);
return list.stream();
})).limit(numPartitionsLimit).collect(Collectors.toList()));
} else if (partialList.size() < numPartitionsLimit && partialList.size() < metadata.numPartitions()) {
partialList.addAll(IntStream.range(0, metadata.numPartitions()).boxed()
.filter(e -> !partialList.contains(e))
.collect(Collectors.collectingAndThen(Collectors.toList(), list -> {
Collections.shuffle(list);
return list.stream();
})).limit(numPartitionsLimit - partialList.size()).collect(Collectors.toList()));
}
}
}
return partialList;
}
}