[120] | 1 | /** |
---|
| 2 | * Licensed to the Apache Software Foundation (ASF) under one |
---|
| 3 | * or more contributor license agreements. See the NOTICE file |
---|
| 4 | * distributed with this work for additional information |
---|
| 5 | * regarding copyright ownership. The ASF licenses this file |
---|
| 6 | * to you under the Apache License, Version 2.0 (the |
---|
| 7 | * "License"); you may not use this file except in compliance |
---|
| 8 | * with the License. You may obtain a copy of the License at |
---|
| 9 | * |
---|
| 10 | * http://www.apache.org/licenses/LICENSE-2.0 |
---|
| 11 | * |
---|
| 12 | * Unless required by applicable law or agreed to in writing, software |
---|
| 13 | * distributed under the License is distributed on an "AS IS" BASIS, |
---|
| 14 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
---|
| 15 | * See the License for the specific language governing permissions and |
---|
| 16 | * limitations under the License. |
---|
| 17 | */ |
---|
| 18 | |
---|
| 19 | package org.apache.hadoop.mapreduce.lib.map; |
---|
| 20 | |
---|
| 21 | import java.io.IOException; |
---|
| 22 | |
---|
| 23 | import org.apache.hadoop.mapreduce.Mapper; |
---|
| 24 | |
---|
| 25 | /** A {@link Mapper} that swaps keys and values. */ |
---|
| 26 | public class InverseMapper<K, V> extends Mapper<K,V,V,K> { |
---|
| 27 | |
---|
| 28 | /** The inverse function. Input keys and values are swapped.*/ |
---|
| 29 | @Override |
---|
| 30 | public void map(K key, V value, Context context |
---|
| 31 | ) throws IOException, InterruptedException { |
---|
| 32 | context.write(value, key); |
---|
| 33 | } |
---|
| 34 | |
---|
| 35 | } |
---|