learning/tour-of-beam/learning-content/windowing/session-window/java-example/Task.java

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 * 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,
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// beam-playground:
//   name: session-window
//   description: Session window example.
//   multifile: false
//   context_line: 50
//   categories:
//     - Quickstart
//   complexity: ADVANCED
//   tags:
//     - hellobeam

import org.apache.beam.sdk.Pipeline;
import org.apache.beam.sdk.options.PipelineOptions;
import org.apache.beam.sdk.options.PipelineOptionsFactory;
import org.apache.beam.sdk.transforms.Create;
import org.apache.beam.sdk.transforms.Min;
import org.apache.beam.sdk.transforms.windowing.FixedWindows;
import org.apache.beam.sdk.transforms.windowing.GlobalWindows;
import org.apache.beam.sdk.transforms.windowing.Sessions;
import org.apache.beam.sdk.transforms.windowing.Window;
import org.apache.beam.sdk.values.PCollection;
import org.apache.beam.sdk.transforms.DoFn;
import org.apache.beam.sdk.transforms.ParDo;
import org.joda.time.Duration;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class Task {

    private static final Logger LOG = LoggerFactory.getLogger(Task.class);

    public static void main(String[] args) {

        LOG.info("Running Task");

        PipelineOptions options = PipelineOptionsFactory.fromArgs(args).create();
        Pipeline pipeline = Pipeline.create(options);

        PCollection<String> input =
                pipeline.apply(
                        Create.of("To", "be", "or", "not", "to", "be","that", "is", "the", "question")
                );


        PCollection<String> sessionWindowedItems = input.apply(
                Window.<String>into(Sessions.withGapDuration(Duration.standardSeconds(600))));

        sessionWindowedItems.apply("Log words", ParDo.of(new LogStrings()));


        pipeline.run();
    }


    public static class LogStrings extends DoFn<String, String> {

        @ProcessElement
        public void processElement(ProcessContext c) throws Exception {
            LOG.info("Processing word: {}", c.element());
            c.output(c.element());
        }
    }
}