/***********************************************************************************************************************
* Copyright (C) 2010-2013 by the Stratosphere project (http://stratosphere.eu)
*
* 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 eu.stratosphere.test.iterative.nephele.customdanglingpagerank;
import java.util.Iterator;
import eu.stratosphere.api.common.functions.AbstractFunction;
import eu.stratosphere.api.common.functions.GenericCombine;
import eu.stratosphere.api.common.functions.GenericGroupReduce;
import eu.stratosphere.test.iterative.nephele.customdanglingpagerank.types.VertexWithRank;
import eu.stratosphere.util.Collector;
public class CustomRankCombiner extends AbstractFunction implements GenericGroupReduce<VertexWithRank, VertexWithRank>,
GenericCombine<VertexWithRank>
{
private static final long serialVersionUID = 1L;
private final VertexWithRank accumulator = new VertexWithRank();
@Override
public void reduce(Iterator<VertexWithRank> records, Collector<VertexWithRank> out) throws Exception {
throw new UnsupportedOperationException();
}
@Override
public void combine(Iterator<VertexWithRank> records, Collector<VertexWithRank> out) throws Exception {
VertexWithRank next = records.next();
this.accumulator.setVertexID(next.getVertexID());
double rank = next.getRank();
while (records.hasNext()) {
rank += records.next().getRank();
}
this.accumulator.setRank(rank);
out.collect(this.accumulator);
}
}