/***********************************************************************************************************************
* 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.recordJobs.graph.pageRankUtil;
import java.io.Serializable;
import eu.stratosphere.api.java.record.functions.JoinFunction;
import eu.stratosphere.types.DoubleValue;
import eu.stratosphere.types.LongValue;
import eu.stratosphere.types.Record;
import eu.stratosphere.util.Collector;
/**
* In schema is_
* INPUT = (pageId, rank, dangling), (pageId, neighbors-list).
* OUTPUT = (targetPageId, partialRank)
*/
public class DotProductMatch extends JoinFunction implements Serializable {
private static final long serialVersionUID = 1L;
private Record record = new Record();
private LongValue vertexID = new LongValue();
private DoubleValue partialRank = new DoubleValue();
private DoubleValue rank = new DoubleValue();
private LongArrayView adjacentNeighbors = new LongArrayView();
@Override
public void join(Record pageWithRank, Record adjacencyList, Collector<Record> collector) throws Exception {
rank = pageWithRank.getField(1, rank);
adjacentNeighbors = adjacencyList.getField(1, adjacentNeighbors);
int numNeighbors = adjacentNeighbors.size();
double rankToDistribute = rank.getValue() / (double) numNeighbors;
partialRank.setValue(rankToDistribute);
record.setField(1, partialRank);
for (int n = 0; n < numNeighbors; n++) {
vertexID.setValue(adjacentNeighbors.getQuick(n));
record.setField(0, vertexID);
collector.collect(record);
}
}
}