/*
* 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.BasicDBObjectBuilder;
import com.mongodb.hadoop.io.MongoUpdateWritable;
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.io.NullWritable;
import org.apache.hadoop.mapreduce.Reducer;
import org.bson.BasicBSONObject;
import java.io.IOException;
import java.util.Date;
/**
* The treasury yield reducer.
*/
public class TreasuryYieldUpdateReducer
extends Reducer<IntWritable, DoubleWritable, NullWritable, MongoUpdateWritable> {
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 query = new BasicBSONObject("_id", pKey.get());
BasicBSONObject modifiers = new BasicBSONObject();
modifiers.put("$set", BasicDBObjectBuilder.start()
.add("count", count)
.add("avg", avg)
.add("sum", sum)
.get());
modifiers.put("$push", new BasicBSONObject("calculatedAt", new Date()));
modifiers.put("$inc", new BasicBSONObject("numCalculations", 1));
pContext.write(null, new MongoUpdateWritable(query, modifiers, true, false));
}
}