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.
   */
  // beam-playground:
  //   name: TextIO
  //   description: TextIO example.
  //   multifile: false
  //   context_line: 36
  //   categories:
  //     - Quickstart
  //   complexity: BASIC
  //   tags:
  //     - hellobeam
  
  package org.apache.beam.examples;
  
  import java.util.Arrays;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import org.apache.beam.sdk.Pipeline;
  import org.apache.beam.sdk.io.TextIO;
  import org.apache.beam.sdk.options.PipelineOptions;
  import org.apache.beam.sdk.options.PipelineOptionsFactory;
  import org.apache.beam.sdk.transforms.Count;
  import org.apache.beam.sdk.transforms.DoFn;
  import org.apache.beam.sdk.transforms.Filter;
  import org.apache.beam.sdk.transforms.Flatten;
  import org.apache.beam.sdk.transforms.FlatMapElements;
  import org.apache.beam.sdk.transforms.MapElements;
  import org.apache.beam.sdk.transforms.ParDo;
  import org.apache.beam.sdk.transforms.PTransform;
  import org.apache.beam.sdk.transforms.Sample;
  import org.apache.beam.sdk.values.KV;
  import org.apache.beam.sdk.values.PCollection;
  import org.apache.beam.sdk.values.TypeDescriptors;
  
  public class Task {
  
      private static final Logger LOG = LoggerFactory.getLogger(Task.class);
  
  
      public static void main(String[] args) {
  
          PipelineOptions options = PipelineOptionsFactory.create();
  
          // Create the Pipeline object with the options we defined above
          Pipeline pipeline = Pipeline.create(options);
  
          // Concept #1. Read text file content line by line. resulting PCollection contains elements, where each element
          // contains a single line of text from the input file.
          PCollection<String> input = pipeline.apply(TextIO.read().from("gs://apache-beam-samples/shakespeare/kinglear.txt"))
                  .apply(Filter.by((String line) -> !line.isEmpty()));
  
          // Concept #2. Output first 10 elements PCollection to the console.
          final PTransform<PCollection<String>, PCollection<Iterable<String>>> sample = Sample.fixedSizeGlobally(10);
  
          PCollection<String> sampleLines = input.apply(sample)
                  .apply(Flatten.iterables())
                  .apply("Log lines", ParDo.of(new LogStrings()));
  
  
          //Concept #3. Read text file and split into PCollection of words.
          PCollection<String> words = pipeline.apply(TextIO.read().from("gs://apache-beam-samples/shakespeare/kinglear.txt"))
                  .apply(FlatMapElements.into(TypeDescriptors.strings()).via((String line) -> Arrays.asList(line.split("[^\\p{L}]+"))))
                  .apply(Filter.by((String word) -> !word.isEmpty()));
  
          PCollection<String> sampleWords = words.apply(sample)
                  .apply(Flatten.iterables())
                  .apply("Log words", ParDo.of(new LogStrings()));
  
          // Concept #4. Write PCollection to text file.
          sampleWords.apply(TextIO.write().to("sample-words"));
          pipeline.run().waitUntilFinish();
      }
  
      public static class LogStrings extends DoFn<String, String> {
  
          @ProcessElement
          public void processElement(ProcessContext c) throws Exception {
              LOG.info("Processing element: {}", c.element());
              c.output(c.element());
          }
      }
  
  }
  