flink-libraries/flink-gelly/src/test/java/org/apache/flink/graph/gsa/GSATranslationTest.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * 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
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 */

package org.apache.flink.graph.gsa;

import org.apache.flink.api.common.aggregators.LongSumAggregator;
import org.apache.flink.api.common.functions.MapFunction;
import org.apache.flink.api.java.DataSet;
import org.apache.flink.api.java.ExecutionEnvironment;
import org.apache.flink.api.java.io.DiscardingOutputFormat;
import org.apache.flink.api.java.operators.DeltaIteration;
import org.apache.flink.api.java.operators.DeltaIterationResultSet;
import org.apache.flink.api.java.operators.SingleInputUdfOperator;
import org.apache.flink.api.java.operators.TwoInputUdfOperator;
import org.apache.flink.api.java.tuple.Tuple3;
import org.apache.flink.graph.Edge;
import org.apache.flink.graph.Graph;
import org.apache.flink.graph.Vertex;
import org.apache.flink.graph.utils.Tuple3ToEdgeMap;
import org.apache.flink.types.NullValue;

import org.junit.Test;

import static org.junit.Assert.assertArrayEquals;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;

/**
 * Test the creation of a {@link GatherSumApplyIteration} program.
 */
public class GSATranslationTest {

	private static final String ITERATION_NAME = "Test Name";

	private static final String AGGREGATOR_NAME = "AggregatorName";

	private static final String BC_SET_GATHER_NAME = "gather messages";

	private static final String BC_SET_SUM_NAME = "sum updates";

	private static final String BC_SET_APLLY_NAME = "apply updates";

	private static final int NUM_ITERATIONS = 13;

	private static final int ITERATION_parallelism = 77;

	@Test
	public void testTranslation() {
		ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();

		DataSet<Long> bcGather = env.fromElements(1L);
		DataSet<Long> bcSum = env.fromElements(1L);
		DataSet<Long> bcApply = env.fromElements(1L);

		DataSet<Vertex<Long, Long>> result;

		// ------------ construct the test program ------------------

		DataSet<Edge<Long, NullValue>> edges = env.fromElements(new Tuple3<>(
			1L, 2L, NullValue.getInstance())).map(new Tuple3ToEdgeMap<>());

		Graph<Long, Long, NullValue> graph = Graph.fromDataSet(edges, new InitVertices(), env);

		GSAConfiguration parameters = new GSAConfiguration();

		parameters.registerAggregator(AGGREGATOR_NAME, new LongSumAggregator());
		parameters.setName(ITERATION_NAME);
		parameters.setParallelism(ITERATION_parallelism);
		parameters.addBroadcastSetForGatherFunction(BC_SET_GATHER_NAME, bcGather);
		parameters.addBroadcastSetForSumFunction(BC_SET_SUM_NAME, bcSum);
		parameters.addBroadcastSetForApplyFunction(BC_SET_APLLY_NAME, bcApply);

		result = graph.runGatherSumApplyIteration(
			new GatherNeighborIds(), new SelectMinId(),
			new UpdateComponentId(), NUM_ITERATIONS, parameters).getVertices();

		result.output(new DiscardingOutputFormat<>());

		// ------------- validate the java program ----------------

		assertTrue(result instanceof DeltaIterationResultSet);

		DeltaIterationResultSet<?, ?> resultSet = (DeltaIterationResultSet<?, ?>) result;
		DeltaIteration<?, ?> iteration = resultSet.getIterationHead();

		// check the basic iteration properties
		assertEquals(NUM_ITERATIONS, resultSet.getMaxIterations());
		assertArrayEquals(new int[]{0}, resultSet.getKeyPositions());
		assertEquals(ITERATION_parallelism, iteration.getParallelism());
		assertEquals(ITERATION_NAME, iteration.getName());

		assertEquals(AGGREGATOR_NAME, iteration.getAggregators().getAllRegisteredAggregators().iterator().next().getName());

		// validate that the semantic properties are set as they should
		TwoInputUdfOperator<?, ?, ?, ?> solutionSetJoin = (TwoInputUdfOperator<?, ?, ?, ?>) resultSet.getNextWorkset();
		assertTrue(solutionSetJoin.getSemanticProperties().getForwardingTargetFields(0, 0).contains(0));
		assertTrue(solutionSetJoin.getSemanticProperties().getForwardingTargetFields(1, 0).contains(0));

		SingleInputUdfOperator<?, ?, ?> sumReduce = (SingleInputUdfOperator<?, ?, ?>) solutionSetJoin.getInput1();
		SingleInputUdfOperator<?, ?, ?> gatherMap = (SingleInputUdfOperator<?, ?, ?>) sumReduce.getInput();

		// validate that the broadcast sets are forwarded
		assertEquals(bcGather, gatherMap.getBroadcastSets().get(BC_SET_GATHER_NAME));
		assertEquals(bcSum, sumReduce.getBroadcastSets().get(BC_SET_SUM_NAME));
		assertEquals(bcApply, solutionSetJoin.getBroadcastSets().get(BC_SET_APLLY_NAME));
	}

	@SuppressWarnings("serial")
	private static final class InitVertices implements MapFunction<Long, Long> {

		public Long map(Long vertexId) {
			return vertexId;
		}
	}

	@SuppressWarnings("serial")
	private static final class GatherNeighborIds extends GatherFunction<Long, NullValue, Long> {

		public Long gather(Neighbor<Long, NullValue> neighbor) {
			return neighbor.getNeighborValue();
		}
	}

	@SuppressWarnings("serial")
	private static final class SelectMinId extends SumFunction<Long, NullValue, Long> {

		public Long sum(Long newValue, Long currentValue) {
			return Math.min(newValue, currentValue);
		}
	}

	@SuppressWarnings("serial")
	private static final class UpdateComponentId extends ApplyFunction<Long, Long, Long> {

		public void apply(Long summedValue, Long origValue) {
			if (summedValue < origValue) {
				setResult(summedValue);
			}
		}
	}
}