/* 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.partition.mapreduce.edge;
import java.io.IOException;
import java.util.Iterator;
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.partition.mapreduce.keyvalue.CombinedEdgeValueType;
import com.intel.hadoop.graphbuilder.partition.mapreduce.keyvalue.IngressKeyType;
import com.intel.hadoop.graphbuilder.partition.mapreduce.keyvalue.IngressValueType;
/**
* Combines intermediate IngressValues.
*
* @param <KeyType>
* @param <ValType>
*/
public class EdgeIngressCombiner<KeyType extends IngressKeyType, ValType extends IngressValueType>
extends MapReduceBase implements
Reducer<KeyType, ValType, KeyType, ValType> {
@Override
public void configure(JobConf job) {
super.configure(job);
this.valClass = job.getMapOutputValueClass();
}
@Override
public void reduce(KeyType key, Iterator<ValType> iter,
OutputCollector<KeyType, ValType> out, Reporter reporter)
throws IOException {
if (!iter.hasNext()) {
return;
}
ValType ret;
try {
ret = (ValType) valClass.newInstance();
if (key.flag() == IngressKeyType.EDGEKEY) {
CombinedEdgeValueType eval = ret.edgeValue();
ret.reduce(IngressKeyType.EDGEKEY, iter);
out.collect(key, ret);
} else if (key.flag() == IngressKeyType.VERTEXKEY) {
ret.reduce(IngressKeyType.VERTEXKEY, iter);
out.collect(key, ret);
}
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
}
protected Class valClass;
}