/***********************************************************************************************************************
* 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;
import java.io.Serializable;
import java.util.Iterator;
import eu.stratosphere.api.common.Plan;
import eu.stratosphere.api.common.Program;
import eu.stratosphere.api.java.record.operators.FileDataSink;
import eu.stratosphere.api.java.record.operators.FileDataSource;
import eu.stratosphere.api.java.record.operators.DeltaIteration;
import eu.stratosphere.api.java.record.functions.CoGroupFunction;
import eu.stratosphere.api.java.record.functions.FunctionAnnotation.ConstantFieldsFirst;
import eu.stratosphere.api.java.record.functions.FunctionAnnotation.ConstantFieldsSecond;
import eu.stratosphere.api.java.record.io.CsvInputFormat;
import eu.stratosphere.api.java.record.io.CsvOutputFormat;
import eu.stratosphere.api.java.record.operators.CoGroupOperator;
import eu.stratosphere.api.java.record.operators.JoinOperator;
import eu.stratosphere.api.java.record.operators.MapOperator;
import eu.stratosphere.test.recordJobs.graph.WorksetConnectedComponents.DuplicateLongMap;
import eu.stratosphere.test.recordJobs.graph.WorksetConnectedComponents.NeighborWithComponentIDJoin;
import eu.stratosphere.types.LongValue;
import eu.stratosphere.types.Record;
import eu.stratosphere.util.Collector;
/**
*
*/
public class ConnectedComponentsWithCoGroup implements Program {
private static final long serialVersionUID = 1L;
@ConstantFieldsFirst(0)
@ConstantFieldsSecond(0)
public static final class MinIdAndUpdate extends CoGroupFunction implements Serializable {
private static final long serialVersionUID = 1L;
private final LongValue newComponentId = new LongValue();
@Override
public void coGroup(Iterator<Record> candidates, Iterator<Record> current, Collector<Record> out) throws Exception {
if (!current.hasNext()) {
throw new Exception("Error: Id not encountered before.");
}
Record old = current.next();
long oldId = old.getField(1, LongValue.class).getValue();
long minimumComponentID = Long.MAX_VALUE;
while (candidates.hasNext()) {
long candidateComponentID = candidates.next().getField(1, LongValue.class).getValue();
if (candidateComponentID < minimumComponentID) {
minimumComponentID = candidateComponentID;
}
}
if (minimumComponentID < oldId) {
newComponentId.setValue(minimumComponentID);
old.setField(1, newComponentId);
out.collect(old);
}
}
}
@SuppressWarnings("unchecked")
@Override
public Plan getPlan(String... args) {
// parse job parameters
final int numSubTasks = (args.length > 0 ? Integer.parseInt(args[0]) : 1);
final String verticesInput = (args.length > 1 ? args[1] : "");
final String edgeInput = (args.length > 2 ? args[2] : "");
final String output = (args.length > 3 ? args[3] : "");
final int maxIterations = (args.length > 4 ? Integer.parseInt(args[4]) : 1);
// data source for initial vertices
FileDataSource initialVertices = new FileDataSource(new CsvInputFormat(' ', LongValue.class), verticesInput, "Vertices");
MapOperator verticesWithId = MapOperator.builder(DuplicateLongMap.class).input(initialVertices).name("Assign Vertex Ids").build();
DeltaIteration iteration = new DeltaIteration(0, "Connected Components Iteration");
iteration.setInitialSolutionSet(verticesWithId);
iteration.setInitialWorkset(verticesWithId);
iteration.setMaximumNumberOfIterations(maxIterations);
// create DataSourceContract for the edges
FileDataSource edges = new FileDataSource(new CsvInputFormat(' ', LongValue.class, LongValue.class), edgeInput, "Edges");
// create CrossOperator for distance computation
JoinOperator joinWithNeighbors = JoinOperator.builder(new NeighborWithComponentIDJoin(), LongValue.class, 0, 0)
.input1(iteration.getWorkset())
.input2(edges)
.name("Join Candidate Id With Neighbor")
.build();
CoGroupOperator minAndUpdate = CoGroupOperator.builder(new MinIdAndUpdate(), LongValue.class, 0, 0)
.input1(joinWithNeighbors)
.input2(iteration.getSolutionSet())
.name("Min Id and Update")
.build();
iteration.setNextWorkset(minAndUpdate);
iteration.setSolutionSetDelta(minAndUpdate);
// create DataSinkContract for writing the new cluster positions
FileDataSink result = new FileDataSink(new CsvOutputFormat(), output, iteration, "Result");
CsvOutputFormat.configureRecordFormat(result)
.recordDelimiter('\n')
.fieldDelimiter(' ')
.field(LongValue.class, 0)
.field(LongValue.class, 1);
// return the PACT plan
Plan plan = new Plan(result, "Workset Connected Components");
plan.setDefaultParallelism(numSubTasks);
return plan;
}
}