| /** |
| * 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.mapreduce.lib.reduce; |
| |
| import java.io.IOException; |
| |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.classification.InterfaceStability; |
| import org.apache.hadoop.io.LongWritable; |
| import org.apache.hadoop.mapreduce.Reducer; |
| |
| @InterfaceAudience.Public |
| @InterfaceStability.Stable |
| public class LongSumReducer<KEY> extends Reducer<KEY, LongWritable, |
| KEY,LongWritable> { |
| |
| private LongWritable result = new LongWritable(); |
| |
| public void reduce(KEY key, Iterable<LongWritable> values, |
| Context context) throws IOException, InterruptedException { |
| long sum = 0; |
| for (LongWritable val : values) { |
| sum += val.get(); |
| } |
| result.set(sum); |
| context.write(key, result); |
| } |
| |
| } |