flink-libraries/flink-gelly/src/test/java/org/apache/flink/graph/pregel/PregelTranslationTest.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
 * limitations under the License.
 */

package org.apache.flink.graph.pregel;

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.Tuple2;
import org.apache.flink.api.java.tuple.Tuple3;
import org.apache.flink.graph.Graph;
import org.apache.flink.graph.Vertex;
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 VertexCentricIteration} program.
 */
@SuppressWarnings("serial")
public class PregelTranslationTest {

	private static final String ITERATION_NAME = "Test Name";

	private static final String AGGREGATOR_NAME = "AggregatorName";

	private static final String BC_SET_NAME = "broadcast messages";

	private static final int NUM_ITERATIONS = 13;

	private static final int ITERATION_parallelism = 77;

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

		DataSet<Long> bcVar = env.fromElements(1L);

		DataSet<Vertex<String, Double>> result;

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

		DataSet<Tuple2<String, Double>> initialVertices = env.fromElements(new Tuple2<>("abc", 3.44));

		DataSet<Tuple2<String, String>> edges = env.fromElements(new Tuple2<>("a", "c"));

		Graph<String, Double, NullValue> graph = Graph.fromTupleDataSet(initialVertices,
			edges.map(new MapFunction<Tuple2<String, String>, Tuple3<String, String, NullValue>>() {

				public Tuple3<String, String, NullValue> map(
					Tuple2<String, String> edge) {
					return new Tuple3<>(edge.f0, edge.f1, NullValue.getInstance());
				}
			}), env);

		VertexCentricConfiguration parameters = new VertexCentricConfiguration();

		parameters.addBroadcastSet(BC_SET_NAME, bcVar);
		parameters.setName(ITERATION_NAME);
		parameters.setParallelism(ITERATION_parallelism);
		parameters.registerAggregator(AGGREGATOR_NAME, new LongSumAggregator());

		result = graph.runVertexCentricIteration(new MyCompute(), null,
			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());

		TwoInputUdfOperator<?, ?, ?, ?> computationCoGroup =
			(TwoInputUdfOperator<?, ?, ?, ?>) ((SingleInputUdfOperator<?, ?, ?>) resultSet.getNextWorkset()).getInput();

		// validate that the broadcast sets are forwarded
		assertEquals(bcVar, computationCoGroup.getBroadcastSets().get(BC_SET_NAME));
	}

	// --------------------------------------------------------------------------------------------

	private static final class MyCompute extends ComputeFunction<String, Double, NullValue, Double> {

		@Override
		public void compute(Vertex<String, Double> vertex, MessageIterator<Double> messages) throws Exception {
		}
	}
}