/***********************************************************************************************************************
* 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.danglingpagerank;
import eu.stratosphere.api.java.record.functions.JoinFunction;
import eu.stratosphere.configuration.Configuration;
import eu.stratosphere.test.iterative.nephele.ConfigUtils;
import eu.stratosphere.types.DoubleValue;
import eu.stratosphere.types.LongValue;
import eu.stratosphere.types.Record;
import eu.stratosphere.util.Collector;
import java.util.Random;
import java.util.Set;
public class CompensatableDotProductMatch extends JoinFunction {
private static final long serialVersionUID = 1L;
private Record record;
private LongValue vertexID;
private DoubleValue partialRank;
private DoubleValue rank = new DoubleValue();
private LongArrayView adjacentNeighbors = new LongArrayView();
private int workerIndex;
private int currentIteration;
private int failingIteration;
private Set<Integer> failingWorkers;
private double messageLoss;
private Random random;
@Override
public void open(Configuration parameters) {
record = new Record();
vertexID = new LongValue();
partialRank = new DoubleValue();
workerIndex = getRuntimeContext().getIndexOfThisSubtask();
currentIteration = getIterationRuntimeContext().getSuperstepNumber();
failingIteration = ConfigUtils.asInteger("compensation.failingIteration", parameters);
failingWorkers = ConfigUtils.asIntSet("compensation.failingWorker", parameters);
messageLoss = ConfigUtils.asDouble("compensation.messageLoss", parameters);
random = new Random();
}
@Override
public void join(Record pageWithRank, Record adjacencyList, Collector<Record> collector) {
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);
boolean isFailure = currentIteration == failingIteration && failingWorkers.contains(workerIndex);
for (int n = 0; n < numNeighbors; n++) {
vertexID.setValue(adjacentNeighbors.getQuick(n));
record.setField(0, vertexID);
if (isFailure) {
if (random.nextDouble() >= messageLoss) {
collector.collect(record);
}
} else {
collector.collect(record);
}
}
}
}