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* distributed with this work for additional information
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* to you 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 org.apache.flink.test.iterative;
import java.util.ArrayList;
import java.util.List;
import org.apache.flink.api.common.functions.RichFlatMapFunction;
import org.apache.flink.api.common.functions.RichGroupReduceFunction;
import org.apache.flink.api.common.functions.RichJoinFunction;
import org.apache.flink.api.java.functions.KeySelector;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.test.util.JavaProgramTestBase;
import org.apache.flink.util.Collector;
import org.apache.flink.api.java.DataSet;
import org.apache.flink.api.java.operators.DeltaIteration;
import org.apache.flink.api.java.ExecutionEnvironment;
/**
*
* Iterative Connected Components test case which recomputes only the elements
* of the solution set whose at least one dependency (in-neighbor) has changed since the last iteration.
* Requires two joins with the solution set.
*
*/
@SuppressWarnings("serial")
public class DependencyConnectedComponentsITCase extends JavaProgramTestBase {
private static final int MAX_ITERATIONS = 20;
private static final int parallelism = 1;
protected static List<Tuple2<Long, Long>> verticesInput = new ArrayList<Tuple2<Long, Long>>();
protected static List<Tuple2<Long, Long>> edgesInput = new ArrayList<Tuple2<Long, Long>>();
private String resultPath;
private String expectedResult;
public DependencyConnectedComponentsITCase(){
setTaskManagerNumSlots(parallelism);
}
@Override
protected void preSubmit() throws Exception {
verticesInput.clear();
edgesInput.clear();
// vertices input
verticesInput.add(new Tuple2<Long, Long>(1l,1l));
verticesInput.add(new Tuple2<Long, Long>(2l,2l));
verticesInput.add(new Tuple2<Long, Long>(3l,3l));
verticesInput.add(new Tuple2<Long, Long>(4l,4l));
verticesInput.add(new Tuple2<Long, Long>(5l,5l));
verticesInput.add(new Tuple2<Long, Long>(6l,6l));
verticesInput.add(new Tuple2<Long, Long>(7l,7l));
verticesInput.add(new Tuple2<Long, Long>(8l,8l));
verticesInput.add(new Tuple2<Long, Long>(9l,9l));
// vertices input
edgesInput.add(new Tuple2<Long, Long>(1l,2l));
edgesInput.add(new Tuple2<Long, Long>(1l,3l));
edgesInput.add(new Tuple2<Long, Long>(2l,3l));
edgesInput.add(new Tuple2<Long, Long>(2l,4l));
edgesInput.add(new Tuple2<Long, Long>(2l,1l));
edgesInput.add(new Tuple2<Long, Long>(3l,1l));
edgesInput.add(new Tuple2<Long, Long>(3l,2l));
edgesInput.add(new Tuple2<Long, Long>(4l,2l));
edgesInput.add(new Tuple2<Long, Long>(4l,6l));
edgesInput.add(new Tuple2<Long, Long>(5l,6l));
edgesInput.add(new Tuple2<Long, Long>(6l,4l));
edgesInput.add(new Tuple2<Long, Long>(6l,5l));
edgesInput.add(new Tuple2<Long, Long>(7l,8l));
edgesInput.add(new Tuple2<Long, Long>(7l,9l));
edgesInput.add(new Tuple2<Long, Long>(8l,7l));
edgesInput.add(new Tuple2<Long, Long>(8l,9l));
edgesInput.add(new Tuple2<Long, Long>(9l,7l));
edgesInput.add(new Tuple2<Long, Long>(9l,8l));
resultPath = getTempDirPath("result");
expectedResult = "(1,1)\n" + "(2,1)\n" + "(3,1)\n" + "(4,1)\n" +
"(5,1)\n" + "(6,1)\n" + "(7,7)\n" + "(8,7)\n" + "(9,7)\n";
}
@Override
protected void testProgram() throws Exception {
DependencyConnectedComponentsProgram.runProgram(resultPath);
}
@Override
protected void postSubmit() throws Exception {
compareResultsByLinesInMemory(expectedResult, resultPath);
}
private static class DependencyConnectedComponentsProgram {
public static String runProgram(String resultPath) throws Exception {
final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
env.setParallelism(parallelism);
DataSet<Tuple2<Long, Long>> initialSolutionSet = env.fromCollection(verticesInput);
DataSet<Tuple2<Long, Long>> edges = env.fromCollection(edgesInput);
int keyPosition = 0;
DeltaIteration<Tuple2<Long, Long>, Tuple2<Long, Long>> iteration =
initialSolutionSet.iterateDelta(initialSolutionSet, MAX_ITERATIONS, keyPosition);
DataSet<Long> candidates = iteration.getWorkset().join(edges).where(0).equalTo(0)
.with(new FindCandidatesJoin())
.groupBy(new KeySelector<Long, Long>() {
public Long getKey(Long id) { return id; }
}).reduceGroup(new RemoveDuplicatesReduce());
DataSet<Tuple2<Long, Long>> candidatesDependencies =
candidates.join(edges)
.where(new KeySelector<Long, Long>() {
public Long getKey(Long id) { return id; }
}).equalTo(new KeySelector<Tuple2<Long, Long>, Long>() {
public Long getKey(Tuple2<Long, Long> vertexWithId)
{ return vertexWithId.f1; }
}).with(new FindCandidatesDependenciesJoin());
DataSet<Tuple2<Long, Long>> verticesWithNewComponents =
candidatesDependencies.join(iteration.getSolutionSet()).where(0).equalTo(0)
.with(new NeighborWithComponentIDJoin())
.groupBy(0).reduceGroup(new MinimumReduce());
DataSet<Tuple2<Long, Long>> updatedComponentId =
verticesWithNewComponents.join(iteration.getSolutionSet()).where(0).equalTo(0)
.flatMap(new MinimumIdFilter());
iteration.closeWith(updatedComponentId, updatedComponentId).writeAsText(resultPath);
env.execute();
return resultPath;
}
}
public static final class FindCandidatesJoin extends RichJoinFunction<Tuple2<Long, Long>, Tuple2<Long, Long>, Long> {
private static final long serialVersionUID = 1L;
@Override
public Long join(Tuple2<Long, Long> vertexWithCompId,
Tuple2<Long, Long> edge) throws Exception {
// emit target vertex
return edge.f1;
}
}
public static final class RemoveDuplicatesReduce extends RichGroupReduceFunction<Long, Long> {
private static final long serialVersionUID = 1L;
@Override
public void reduce(Iterable<Long> values, Collector<Long> out) {
out.collect(values.iterator().next());
}
}
public static final class FindCandidatesDependenciesJoin extends RichJoinFunction<Long, Tuple2<Long, Long>,Tuple2<Long, Long>> {
private static final long serialVersionUID = 1L;
@Override
public Tuple2<Long, Long> join(Long candidateId, Tuple2<Long, Long> edge) throws Exception {
return edge;
}
}
public static final class NeighborWithComponentIDJoin extends RichJoinFunction<Tuple2<Long, Long>, Tuple2<Long, Long>, Tuple2<Long, Long>> {
private static final long serialVersionUID = 1L;
@Override
public Tuple2<Long, Long> join(Tuple2<Long, Long> edge,
Tuple2<Long, Long> vertexWithCompId) throws Exception {
vertexWithCompId.setField(edge.f1, 0);
return vertexWithCompId;
}
}
public static final class MinimumReduce extends RichGroupReduceFunction<Tuple2<Long, Long>, Tuple2<Long, Long>> {
private static final long serialVersionUID = 1L;
final Tuple2<Long, Long> resultVertex = new Tuple2<Long, Long>();
@Override
public void reduce(Iterable<Tuple2<Long, Long>> values, Collector<Tuple2<Long, Long>> out) {
Long vertexId = 0L;
Long minimumCompId = Long.MAX_VALUE;
for (Tuple2<Long, Long> value: values) {
vertexId = value.f0;
Long candidateCompId = value.f1;
if (candidateCompId < minimumCompId) {
minimumCompId = candidateCompId;
}
}
resultVertex.f0 = vertexId;
resultVertex.f1 = minimumCompId;
out.collect(resultVertex);
}
}
public static final class MinimumIdFilter extends RichFlatMapFunction<Tuple2<Tuple2<Long, Long>, Tuple2<Long, Long>>, Tuple2<Long, Long>> {
private static final long serialVersionUID = 1L;
@Override
public void flatMap(
Tuple2<Tuple2<Long, Long>, Tuple2<Long, Long>> vertexWithNewAndOldId,
Collector<Tuple2<Long, Long>> out)
{
if ( vertexWithNewAndOldId.f0.f1 < vertexWithNewAndOldId.f1.f1 ) {
out.collect(vertexWithNewAndOldId.f0);
}
}
}
}