| /** |
| * 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.tez.engine.api; |
| |
| import org.apache.hadoop.conf.Configuration; |
| import org.apache.tez.common.TezJobConfig; |
| |
| /** |
| * {@link Partitioner} is used by the TEZ framework to partition output |
| * key/value pairs. |
| * |
| * <b>Partitioner Initialization</b></p> The Partitioner class is picked up |
| * using the TEZ_ENGINE_PARTITIONER_CLASS attribute in {@link TezJobConfig} |
| * |
| * TODO NEWTEZ Change construction to first check for a Constructor with a bytep[] payload |
| * |
| * Partitioners need to provide a single argument ({@link Configuration}) |
| * constructor or a 0 argument constructor. If both exist, preference is given |
| * to the single argument constructor. This is primarily for MR support. |
| * |
| * If using the configuration constructor, TEZ_ENGINE_NUM_EXPECTED_PARTITIONS |
| * will be set in the configuration, to indicate the max number of expected |
| * partitions. |
| * |
| */ |
| public interface Partitioner { |
| |
| /** |
| * Get partition for given key/value. |
| * @param key key |
| * @param value value |
| * @param numPartitions number of partitions |
| * @return |
| */ |
| int getPartition(Object key, Object value, int numPartitions); |
| |
| } |