/* Copyright (C) 2012 Intel Corporation.
* All rights reserved.
*
* 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.
*
* For more about this software visit:
* http://www.01.org/GraphBuilder
*/
package com.intel.hadoop.graphbuilder.preprocess.mapreduce;
import java.io.IOException;
import java.util.Iterator;
import org.apache.hadoop.io.WritableComparable;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.MapReduceBase;
import org.apache.hadoop.mapred.OutputCollector;
import org.apache.hadoop.mapred.Reducer;
import org.apache.hadoop.mapred.Reporter;
import com.intel.hadoop.graphbuilder.preprocess.mapreduce.keyvalue.PairListType;
/**
* Combine the intermediate key value pairs.
*
*
* @param <KeyType>
* @param <ValType>
*/
public class EdgeTransformCombiner<VidType extends WritableComparable<VidType>>
extends MapReduceBase implements
Reducer<VidType, PairListType, VidType, PairListType> {
@Override
public void configure(JobConf job) {
super.configure(job);
this.valClass = job.getMapOutputValueClass();
}
@Override
public void reduce(VidType key, Iterator<PairListType> values,
OutputCollector<VidType, PairListType> out, Reporter reporter)
throws IOException {
PairListType ret;
try {
ret = (PairListType) valClass.newInstance();
while (values.hasNext()) {
ret.append(values.next());
}
out.collect(key, ret);
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
}
protected Class valClass;
}