| /** |
| * 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.hadoop.mapred.pipes; |
| |
| import org.apache.hadoop.io.Writable; |
| import org.apache.hadoop.io.WritableComparable; |
| import org.apache.hadoop.mapred.JobConf; |
| import org.apache.hadoop.mapred.Partitioner; |
| import org.apache.hadoop.util.ReflectionUtils; |
| |
| /** |
| * This partitioner is one that can either be set manually per a record or it |
| * can fall back onto a Java partitioner that was set by the user. |
| */ |
| class PipesPartitioner<K extends WritableComparable, |
| V extends Writable> |
| implements Partitioner<K, V> { |
| |
| private static final ThreadLocal<Integer> CACHE = new ThreadLocal<Integer>(); |
| private Partitioner<K, V> part = null; |
| |
| @SuppressWarnings("unchecked") |
| public void configure(JobConf conf) { |
| part = |
| ReflectionUtils.newInstance(Submitter.getJavaPartitioner(conf), conf); |
| } |
| |
| /** |
| * Set the next key to have the given partition. |
| * @param newValue the next partition value |
| */ |
| static void setNextPartition(int newValue) { |
| CACHE.set(newValue); |
| } |
| |
| /** |
| * If a partition result was set manually, return it. Otherwise, we call |
| * the Java partitioner. |
| * @param key the key to partition |
| * @param value the value to partition |
| * @param numPartitions the number of reduces |
| */ |
| public int getPartition(K key, V value, |
| int numPartitions) { |
| Integer result = CACHE.get(); |
| if (result == null) { |
| return part.getPartition(key, value, numPartitions); |
| } else { |
| return result; |
| } |
| } |
| |
| } |