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    }