/*
* Copyright 2011 10gen Inc.
*
* Licensed 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 com.mongodb.hadoop.examples.treasury;
import com.mongodb.hadoop.io.BSONWritable;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.io.DoubleWritable;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.OutputCollector;
import org.apache.hadoop.mapred.Reporter;
import org.apache.hadoop.mapreduce.Reducer;
import org.bson.BasicBSONObject;
import java.io.IOException;
import java.util.Iterator;
/**
* The treasury yield reducer.
*/
public class TreasuryYieldReducer
extends Reducer<IntWritable, DoubleWritable, IntWritable, BSONWritable>
implements org.apache.hadoop.mapred.Reducer<IntWritable, DoubleWritable, IntWritable, BSONWritable> {
private static final Log LOG = LogFactory.getLog(TreasuryYieldReducer.class);
@Override
public void reduce(final IntWritable pKey, final Iterable<DoubleWritable> pValues, final Context pContext)
throws IOException, InterruptedException {
int count = 0;
double sum = 0;
for (final DoubleWritable value : pValues) {
sum += value.get();
count++;
}
final double avg = sum / count;
LOG.debug("Average 10 Year Treasury for " + pKey.get() + " was " + avg);
BasicBSONObject output = new BasicBSONObject();
output.put("count", count);
output.put("avg", avg);
output.put("sum", sum);
pContext.write(pKey, new BSONWritable(output));
}
@Override
public void reduce(final IntWritable key, final Iterator<DoubleWritable> values,
final OutputCollector<IntWritable, BSONWritable> output,
final Reporter reporter) throws IOException {
int count = 0;
double sum = 0;
while (values.hasNext()) {
sum += values.next().get();
count++;
}
final double avg = sum / count;
LOG.debug("Average 10 Year Treasury for " + key.get() + " was " + avg);
BasicBSONObject bsonObject = new BasicBSONObject();
bsonObject.put("count", count);
bsonObject.put("avg", avg);
bsonObject.put("sum", sum);
output.collect(key, new BSONWritable(bsonObject));
}
@Override
public void close() throws IOException {
}
@Override
public void configure(final JobConf job) {
}
}