content: /*
   * 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.beam.learning.katas.triggers.earlytriggers;
  
  // beam-playground:
  //   name: EarlyTriggers
  //   description: Task from katas to count events using early triggers
  //   multifile: true
  //   context_line: 50
  //   categories:
  //     - Streaming
  //   complexity: MEDIUM
  //   tags:
  //     - windowing
  //     - triggers
  //     - event
  
  
  import org.apache.beam.learning.katas.util.Log;
  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.Combine;
  import org.apache.beam.sdk.transforms.Count;
  import org.apache.beam.sdk.transforms.windowing.AfterProcessingTime;
  import org.apache.beam.sdk.transforms.windowing.AfterWatermark;
  import org.apache.beam.sdk.transforms.windowing.FixedWindows;
  import org.apache.beam.sdk.transforms.windowing.Window;
  import org.apache.beam.sdk.values.PCollection;
  import org.joda.time.Duration;
  
  public class Task {
  
    public static void main(String[] args) {
      PipelineOptions options = PipelineOptionsFactory.fromArgs(args).create();
      Pipeline pipeline = Pipeline.create(options);
  
      PCollection<String> events =
          pipeline.apply(GenerateEvent.everySecond());
  
      PCollection<Long> output = applyTransform(events);
  
      output.apply(Log.ofElements());
  
      pipeline.run();
    }
  
    static PCollection<Long> applyTransform(PCollection<String> events) {
      return events
          .apply(
              Window.<String>into(FixedWindows.of(Duration.standardDays(1)))
                  .triggering(
                      AfterWatermark.pastEndOfWindow()
                      .withEarlyFirings(
                          AfterProcessingTime.pastFirstElementInPane()))
                  .withAllowedLateness(Duration.ZERO)
                  .discardingFiredPanes())
  
          .apply(Combine.globally(Count.<String>combineFn()).withoutDefaults());
    }
  
  }