flink-tests/src/test/java/org/apache/flink/test/iterative/IterationWithUnionITCase.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.test.iterative;

import org.apache.flink.api.common.functions.GroupReduceFunction;
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.operators.IterativeDataSet;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.test.util.CoordVector;
import org.apache.flink.test.util.JavaProgramTestBase;
import org.apache.flink.test.util.PointFormatter;
import org.apache.flink.test.util.PointInFormat;
import org.apache.flink.util.Collector;

import java.io.Serializable;

/** Test iteration with union. */
public class IterationWithUnionITCase extends JavaProgramTestBase {

    private static final String DATAPOINTS =
            "0|50.90|16.20|72.08|\n" + "1|73.65|61.76|62.89|\n" + "2|61.73|49.95|92.74|\n";

    protected String dataPath;
    protected String resultPath;

    @Override
    protected void preSubmit() throws Exception {
        dataPath = createTempFile("datapoints.txt", DATAPOINTS);
        resultPath = getTempDirPath("union_iter_result");
    }

    @Override
    protected void postSubmit() throws Exception {
        compareResultsByLinesInMemory(
                DATAPOINTS + DATAPOINTS + DATAPOINTS + DATAPOINTS, resultPath);
    }

    @Override
    protected void testProgram() throws Exception {
        ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();

        DataSet<Tuple2<Integer, CoordVector>> initialInput =
                env.readFile(new PointInFormat(), this.dataPath).setParallelism(1);

        IterativeDataSet<Tuple2<Integer, CoordVector>> iteration = initialInput.iterate(2);

        DataSet<Tuple2<Integer, CoordVector>> result =
                iteration.union(iteration).map(new IdentityMapper());

        iteration.closeWith(result).writeAsFormattedText(this.resultPath, new PointFormatter());

        env.execute();
    }

    static final class IdentityMapper
            implements MapFunction<Tuple2<Integer, CoordVector>, Tuple2<Integer, CoordVector>>,
                    Serializable {
        private static final long serialVersionUID = 1L;

        @Override
        public Tuple2<Integer, CoordVector> map(Tuple2<Integer, CoordVector> rec) {
            return rec;
        }
    }

    static class DummyReducer
            implements GroupReduceFunction<
                            Tuple2<Integer, CoordVector>, Tuple2<Integer, CoordVector>>,
                    Serializable {
        private static final long serialVersionUID = 1L;

        @Override
        public void reduce(
                Iterable<Tuple2<Integer, CoordVector>> it,
                Collector<Tuple2<Integer, CoordVector>> out) {
            for (Tuple2<Integer, CoordVector> r : it) {
                out.collect(r);
            }
        }
    }
}