| /* |
| * 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.dsl.partitioner |
| |
| import org.apache.gearpump.Message |
| import org.apache.gearpump.partitioner.UnicastPartitioner |
| import org.apache.gearpump.streaming.dsl.window.api.GroupByFn |
| |
| /** |
| * Partition messages by applying group by function first. |
| * |
| * For example: |
| * {{{ |
| * case class People(name: String, gender: String) |
| * |
| * object Test{ |
| * |
| * val groupBy: (People => String) = people => people.gender |
| * val partitioner = GroupByPartitioner(groupBy) |
| * } |
| * }}} |
| * |
| * @param fn First apply message with groupBy function, then pick the hashCode of the output |
| * to do the partitioning. You must define hashCode() for output type of groupBy function. |
| */ |
| class GroupByPartitioner[T, Group](fn: GroupByFn[T, Group]) |
| extends UnicastPartitioner { |
| override def getPartition(message: Message, partitionNum: Int, currentPartitionId: Int): Int = { |
| val hashCode = fn.groupBy(message).hashCode() |
| (hashCode & Integer.MAX_VALUE) % partitionNum |
| } |
| } |
| |