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
019package org.apache.hadoop.mapred.lib;
020
021import org.apache.hadoop.classification.InterfaceAudience;
022import org.apache.hadoop.classification.InterfaceStability;
023import org.apache.hadoop.mapred.JobConf;
024import 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
040public 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}