content: package hip.ch3.avro;
  
  import hip.ch3.avro.gen.Stock;
  import hip.ch3.avro.gen.StockAvg;
  import hip.util.Cli;
  import hip.util.CliCommonOpts;
  import org.apache.avro.Schema;
  import org.apache.avro.mapred.AvroKey;
  import org.apache.avro.mapred.AvroValue;
  import org.apache.avro.mapreduce.*;
  import org.apache.commons.math.stat.descriptive.moment.Mean;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.conf.Configured;
  import org.apache.hadoop.fs.Path;
  import org.apache.hadoop.io.DoubleWritable;
  import org.apache.hadoop.io.Text;
  import org.apache.hadoop.mapreduce.Job;
  import org.apache.hadoop.mapreduce.Mapper;
  import org.apache.hadoop.mapreduce.Reducer;
  import org.apache.hadoop.mapreduce.lib.input.*;
  import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
  import org.apache.hadoop.util.Tool;
  import org.apache.hadoop.util.ToolRunner;
  
  import java.io.IOException;
  
  public class AvroKeyValueMapReduce extends Configured implements Tool {
  
    /**
     * Main entry point for the example.
     *
     * @param args arguments
     * @throws Exception when something goes wrong
     */
    public static void main(final String[] args) throws Exception {
      int res = ToolRunner.run(new Configuration(), new AvroKeyValueMapReduce(), args);
      System.exit(res);
    }
  
    /**
     * The MapReduce driver - setup and launch the job.
     *
     * @param args the command-line arguments
     * @return the process exit code
     * @throws Exception if something goes wrong
     */
    public int run(final String[] args) throws Exception {
  
      Cli cli = Cli.builder().setArgs(args).addOptions(CliCommonOpts.MrIoOpts.values()).build();
      int result = cli.runCmd();
  
      if (result != 0) {
        return result;
      }
  
      Path inputPath = new Path(cli.getArgValueAsString(CliCommonOpts.MrIoOpts.INPUT));
      Path outputPath = new Path(cli.getArgValueAsString(CliCommonOpts.MrIoOpts.OUTPUT));
  
      Configuration conf = super.getConf();
  
      Job job = new Job(conf);
      job.setJarByClass(AvroKeyValueMapReduce.class);
  
      FileInputFormat.setInputPaths(job, inputPath);
      job.setInputFormatClass(AvroKeyValueInputFormat.class);
      AvroJob.setInputKeySchema(job, Schema.create(Schema.Type.STRING));
      AvroJob.setInputValueSchema(job, Stock.SCHEMA$);
  
      job.setMapperClass(Map.class);
      job.setReducerClass(Reduce.class);
  
      job.setMapOutputKeyClass(Text.class);
      job.setMapOutputValueClass(DoubleWritable.class);
  
      job.setOutputKeyClass(Text.class);
      job.setOutputValueClass(AvroValue.class);
      job.setOutputFormatClass(AvroKeyValueOutputFormat.class);
      AvroJob.setOutputValueSchema(job, StockAvg.SCHEMA$);
  
      FileOutputFormat.setOutputPath(job, outputPath);
  
      return job.waitForCompletion(true) ? 0 : 1;
    }
  
    public static class Map extends Mapper<AvroKey<CharSequence>, AvroValue<Stock>, Text, DoubleWritable> {
  
      @Override
      public void map(AvroKey<CharSequence> key,
                      AvroValue<Stock> value,
                      Context context) throws IOException, InterruptedException {
        context.write(new Text(key.toString()),
            new DoubleWritable(value.datum().getOpen()));
      }
    }
  
    public static class Reduce extends Reducer<Text, DoubleWritable, Text, AvroValue<StockAvg>> {
  
      @Override
      protected void reduce(Text key, Iterable<DoubleWritable> values, Context context) throws IOException, InterruptedException {
        Mean mean = new Mean();
        for (DoubleWritable val: values) {
          mean.increment(val.get());
        }
        StockAvg avg = new StockAvg();
        avg.setSymbol(key.toString());
        avg.setAvg(mean.getResult());
        context.write(key, new AvroValue<StockAvg>(avg));
      }
    }
  }
  