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: setting-pipeline
  //   description: Setting pipeline example.
  //   multifile: false
  //   pipeline_options: --output output.txt
  //   context_line: 33
  //   categories:
  //     - Quickstart
  //   complexity: BASIC
  //   tags:
  //     - hellobeam
  
  import org.apache.beam.sdk.Pipeline;
  import org.apache.beam.sdk.io.TextIO;
  import org.apache.beam.sdk.options.*;
  import org.apache.beam.sdk.values.PCollection;
  import org.apache.beam.sdk.transforms.*;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  public class Task {
  
      private static final Logger LOG = LoggerFactory.getLogger(Task.class);
  
      public interface MyOptions extends PipelineOptions {
          // Default value if [--inputFile] equal null
          @Description("Path of the file to read from")
          @Default.String("gs://apache-beam-samples/shakespeare/kinglear.txt")
          String getInputFile();
  
          void setInputFile(String value);
  
  
          // Set this required option to specify where to write the output.
          @Description("Path of the file to write to")
          @Validation.Required
          String getOutput();
  
          void setOutput(String value);
      }
  
      public static void main(String[] args) {
          MyOptions options = PipelineOptionsFactory.fromArgs(args).withValidation().as(MyOptions.class);
  
          readLines(options);
      }
  
      static void readLines(MyOptions options) {
          Pipeline pipeline = Pipeline.create(options);
          PCollection<String> output = pipeline.apply("ReadLines", TextIO.read().from(options.getInputFile()))
                  .apply(Filter.by((String line) -> !line.isEmpty()));
  
          output.apply("Log", ParDo.of(new LogOutput<String>()));
          pipeline.run().waitUntilFinish();
      }
  
      static class LogOutput<T> extends DoFn<T, T> {
          private String prefix;
  
          LogOutput() {
              this.prefix = "Processing element";
          }
  
          LogOutput(String prefix) {
              this.prefix = prefix;
          }
  
          @ProcessElement
          public void processElement(ProcessContext c) throws Exception {
              LOG.info(prefix + ": {}", c.element());
          }
      }
  }
  