| /* |
| * 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.gearpump.streaming.partitioner |
| |
| import org.apache.gearpump.Message |
| |
| import scala.util.Random |
| |
| /** |
| * The idea of ShuffleGroupingPartitioner is derived from Storm. |
| * Messages are randomly distributed across the downstream's tasks in a way such that |
| * each task is guaranteed to get an equal number of messages. |
| */ |
| class ShuffleGroupingPartitioner extends UnicastPartitioner { |
| private val random = new Random |
| private var index = -1 |
| private var partitions = List.empty[Int] |
| override def getPartition(msg: Message, partitionNum: Int, currentPartitionId: Int): Int = { |
| index += 1 |
| if (partitions.isEmpty) { |
| partitions = 0.until(partitionNum).toList |
| partitions = random.shuffle(partitions) |
| } else if (index >= partitionNum) { |
| index = 0 |
| partitions = random.shuffle(partitions) |
| } |
| partitions(index) |
| } |
| } |