/**
* 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.mahout.fpm.pfpgrowth;
import java.io.IOException;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Reducer;
/**
* sums up the item count and output the item and the count This can also be
* used as a local Combiner. A simple summing reducer
*/
public class ParallelCountingReducer extends Reducer<Text,LongWritable,Text,LongWritable> {
@Override
protected void reduce(Text key, Iterable<LongWritable> values, Context context) throws IOException,
InterruptedException {
long sum = 0;
for (LongWritable value : values) {
context.setStatus("Parallel Counting Reducer :" + key);
sum += value.get();
}
context.setStatus("Parallel Counting Reducer: " + key + " => " + sum);
context.write(key, new LongWritable(sum));
}
}