org.myorg.quickstart.FlinkForward2016.java Source code

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Here is the source code for org.myorg.quickstart.FlinkForward2016.java

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package org.myorg.quickstart;

/**
 * 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.
 */

import org.apache.beam.runners.flink.FlinkPipelineOptions;
import org.apache.beam.runners.flink.FlinkRunner;
import org.apache.beam.sdk.Pipeline;
import org.apache.beam.sdk.coders.BigEndianLongCoder;
import org.apache.beam.sdk.coders.Coder;
import org.apache.beam.sdk.coders.SerializableCoder;
import org.apache.beam.sdk.io.Read;
import org.apache.beam.sdk.io.UnboundedSource;
import org.apache.beam.sdk.options.PipelineOptions;
import org.apache.beam.sdk.options.PipelineOptionsFactory;
import org.apache.beam.sdk.transforms.*;
import org.apache.beam.sdk.transforms.windowing.*;
import org.apache.beam.sdk.values.PCollection;
import org.joda.time.Duration;
import org.joda.time.Instant;

import javax.annotation.Nullable;
import java.io.IOException;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;
import java.util.NoSuchElementException;

/**
 * Counting application for FlinkForward 2016
 */
public class FlinkForward2016 {

    public static void main(String[] args) throws Exception {

        PipelineOptions options = PipelineOptionsFactory.fromArgs(args).as(FlinkPipelineOptions.class);
        options.setRunner(FlinkRunner.class);

        Pipeline p = Pipeline.create(options);

        PCollection<Long> source = p.apply(Read.from(new MySource()));

        source.apply(Window.<Long>into(FixedWindows.of(Duration.standardSeconds(3)))
                .triggering(AfterWatermark.pastEndOfWindow()).withAllowedLateness(Duration.ZERO)
                .discardingFiredPanes())

                .apply(Combine.globally(new PrintWindowCounts()).withoutDefaults());

        p.run();
    }

    private static class PrintWindowCounts implements SerializableFunction<Iterable<Long>, Long> {

        @Override
        public Long apply(Iterable<Long> input) {
            long count = 0;
            for (long val : input) {
                System.out.println(val);
                count += val;
            }
            return count;
        }
    }

    private static class MySource extends UnboundedSource<Long, LongCheckpointMark> {

        @Override
        public List<? extends UnboundedSource<Long, LongCheckpointMark>> generateInitialSplits(int desiredSplits,
                PipelineOptions pipelineOptions) throws Exception {
            List<MySource> sources = new ArrayList<>(desiredSplits);
            for (int i = 0; i < desiredSplits; i++) {
                sources.add(new MySource());
            }
            return sources;
        }

        @Override
        public UnboundedReader<Long> createReader(PipelineOptions pipelineOptions,
                @Nullable LongCheckpointMark longCheckpointMark) throws IOException {
            return new Reader(this, longCheckpointMark);
        }

        @Nullable
        @Override
        public Coder<LongCheckpointMark> getCheckpointMarkCoder() {
            return SerializableCoder.of(LongCheckpointMark.class);
        }

        @Override
        public void validate() {
        }

        @Override
        public Coder<Long> getDefaultOutputCoder() {
            return BigEndianLongCoder.of();
        }

        static class Reader extends UnboundedReader<Long> {

            private final UnboundedSource<Long, LongCheckpointMark> origin;
            private long currentOffset = 0;

            public Reader(UnboundedSource<Long, LongCheckpointMark> origin) {
                this(origin, null);
            }

            public Reader(UnboundedSource<Long, LongCheckpointMark> origin, LongCheckpointMark checkpointMark) {
                this.origin = origin;

                if (checkpointMark != null) {
                    //System.out.println("Restoring from " + checkpointMark);
                    this.currentOffset = checkpointMark.offset;
                }
            }

            @Override
            public boolean start() throws IOException {
                return true;
            }

            @Override
            public boolean advance() throws IOException {
                currentOffset++;
                try {
                    Thread.sleep(500);
                } catch (InterruptedException ignored) {
                }
                return true;
            }

            @Override
            public Long getCurrent() throws NoSuchElementException {
                return currentOffset;
            }

            @Override
            public Instant getCurrentTimestamp() throws NoSuchElementException {
                return new Instant(currentOffset * 1000);
            }

            @Override
            public void close() throws IOException {
            }

            @Override
            public Instant getWatermark() {
                return new Instant(currentOffset * 1000);
            }

            @Override
            public CheckpointMark getCheckpointMark() {
                return new LongCheckpointMark(currentOffset);
            }

            @Override
            public UnboundedSource<Long, ?> getCurrentSource() {
                return origin;
            }
        }
    }

    private static class LongCheckpointMark implements UnboundedSource.CheckpointMark, Serializable {

        private final long offset;

        public LongCheckpointMark(long offset) {
            this.offset = offset;
        }

        @Override
        public void finalizeCheckpoint() throws IOException {
        }

        @Override
        public String toString() {
            return "LongCheckpointMark{" + "offset=" + offset + '}';
        }
    }

}