flink-tests/src/test/java/org/apache/flink/test/iterative/StaticlyNestedIterationsITCase.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.JoinFunction;
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.functions.KeySelector;
import org.apache.flink.api.java.io.DiscardingOutputFormat;
import org.apache.flink.api.java.operators.IterativeDataSet;
import org.apache.flink.test.util.JavaProgramTestBase;

/** Test iterations referenced from the static path of other iterations. */
public class StaticlyNestedIterationsITCase extends JavaProgramTestBase {

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

        DataSet<Long> data1 = env.generateSequence(1, 100);
        DataSet<Long> data2 = env.generateSequence(1, 100);

        IterativeDataSet<Long> firstIteration = data1.iterate(100);

        DataSet<Long> firstResult = firstIteration.closeWith(firstIteration.map(new IdMapper()));

        IterativeDataSet<Long> mainIteration = data2.map(new IdMapper()).iterate(100);

        DataSet<Long> joined =
                mainIteration
                        .join(firstResult)
                        .where(new IdKeyExtractor())
                        .equalTo(new IdKeyExtractor())
                        .with(new Joiner());

        DataSet<Long> mainResult = mainIteration.closeWith(joined);

        mainResult.output(new DiscardingOutputFormat<Long>());

        env.execute();
    }

    private static class IdKeyExtractor implements KeySelector<Long, Long> {

        private static final long serialVersionUID = 1L;

        @Override
        public Long getKey(Long value) {
            return value;
        }
    }

    private static class IdMapper implements MapFunction<Long, Long> {

        private static final long serialVersionUID = 1L;

        @Override
        public Long map(Long value) {
            return value;
        }
    }

    private static class Joiner implements JoinFunction<Long, Long, Long> {

        private static final long serialVersionUID = 1L;

        @Override
        public Long join(Long first, Long second) {
            return first;
        }
    }
}