001 /**
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements. See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership. The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License. You may obtain a copy of the License at
009 *
010 * http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018
019 package org.apache.hadoop.mapred.lib;
020
021 import org.apache.hadoop.classification.InterfaceAudience;
022 import org.apache.hadoop.classification.InterfaceStability;
023 import org.apache.hadoop.mapred.JobConf;
024 import org.apache.hadoop.mapred.Partitioner;
025
026 /**
027 * Defines a way to partition keys based on certain key fields (also see
028 * {@link KeyFieldBasedComparator}.
029 * The key specification supported is of the form -k pos1[,pos2], where,
030 * pos is of the form f[.c][opts], where f is the number
031 * of the key field to use, and c is the number of the first character from
032 * the beginning of the field. Fields and character posns are numbered
033 * starting with 1; a character position of zero in pos2 indicates the
034 * field's last character. If '.c' is omitted from pos1, it defaults to 1
035 * (the beginning of the field); if omitted from pos2, it defaults to 0
036 * (the end of the field).
037 */
038 @InterfaceAudience.Public
039 @InterfaceStability.Stable
040 public class KeyFieldBasedPartitioner<K2, V2> extends
041 org.apache.hadoop.mapreduce.lib.partition.KeyFieldBasedPartitioner<K2, V2>
042 implements Partitioner<K2, V2> {
043
044 public void configure(JobConf job) {
045 super.setConf(job);
046 }
047 }