| /* |
| * 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.client.impl; |
| |
| import static org.apache.pulsar.client.util.MathUtils.signSafeMod; |
| import java.time.Clock; |
| import java.util.concurrent.atomic.AtomicIntegerFieldUpdater; |
| import org.apache.pulsar.client.api.HashingScheme; |
| import org.apache.pulsar.client.api.Message; |
| import org.apache.pulsar.client.api.TopicMetadata; |
| |
| /** |
| * The routing strategy here: |
| * <ul> |
| * <li>If a key is present, choose a partition based on a hash of the key. |
| * <li>If no key is present, choose a partition in a "round-robin" fashion. Batching-Awareness is built-in to improve |
| * batching locality. |
| * </ul> |
| */ |
| public class RoundRobinPartitionMessageRouterImpl extends MessageRouterBase { |
| |
| private static final long serialVersionUID = 1L; |
| |
| private static final AtomicIntegerFieldUpdater<RoundRobinPartitionMessageRouterImpl> PARTITION_INDEX_UPDATER = |
| AtomicIntegerFieldUpdater.newUpdater(RoundRobinPartitionMessageRouterImpl.class, "partitionIndex"); |
| @SuppressWarnings("unused") |
| private volatile int partitionIndex = 0; |
| |
| private final int startPtnIdx; |
| private final boolean isBatchingEnabled; |
| private final long partitionSwitchMs; |
| |
| private final Clock clock; |
| |
| private static final Clock SYSTEM_CLOCK = Clock.systemUTC(); |
| |
| public RoundRobinPartitionMessageRouterImpl(HashingScheme hashingScheme, |
| int startPtnIdx, |
| boolean isBatchingEnabled, |
| long partitionSwitchMs) { |
| this(hashingScheme, startPtnIdx, isBatchingEnabled, partitionSwitchMs, SYSTEM_CLOCK); |
| } |
| |
| public RoundRobinPartitionMessageRouterImpl(HashingScheme hashingScheme, |
| int startPtnIdx, |
| boolean isBatchingEnabled, |
| long partitionSwitchMs, |
| Clock clock) { |
| super(hashingScheme); |
| PARTITION_INDEX_UPDATER.set(this, startPtnIdx); |
| this.startPtnIdx = startPtnIdx; |
| this.isBatchingEnabled = isBatchingEnabled; |
| this.partitionSwitchMs = Math.max(1, partitionSwitchMs); |
| this.clock = clock; |
| } |
| |
| @Override |
| public int choosePartition(Message<?> msg, TopicMetadata topicMetadata) { |
| // If the message has a key, it supersedes the round robin routing policy |
| if (msg.hasKey()) { |
| return signSafeMod(hash.makeHash(msg.getKey()), topicMetadata.numPartitions()); |
| } |
| |
| if (isBatchingEnabled) { // if batching is enabled, choose partition on `partitionSwitchMs` boundary. |
| long currentMs = clock.millis(); |
| return signSafeMod(currentMs / partitionSwitchMs + startPtnIdx, topicMetadata.numPartitions()); |
| } else { |
| return signSafeMod(PARTITION_INDEX_UPDATER.getAndIncrement(this), topicMetadata.numPartitions()); |
| } |
| } |
| |
| } |