// cc MaxTemperatureWithCounters Application to run the maximum temperature job, including counting missing and malformed fields and quality codes
import java.io.IOException;

import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;

// vv MaxTemperatureWithCounters
public class MaxTemperatureWithCounters extends Configured implements Tool {
  
  enum Temperature {
    MISSING,
    MALFORMED
  }
  
  static class MaxTemperatureMapperWithCounters
    extends Mapper<LongWritable, Text, Text, IntWritable> {
    
    private NcdcRecordParser parser = new NcdcRecordParser();
  
    @Override
    protected void map(LongWritable key, Text value, Context context)
        throws IOException, InterruptedException {
      
      parser.parse(value);
      if (parser.isValidTemperature()) {
        int airTemperature = parser.getAirTemperature();
        context.write(new Text(parser.getYear()),
            new IntWritable(airTemperature));
      } else if (parser.isMalformedTemperature()) {
        System.err.println("Ignoring possibly corrupt input: " + value);
        context.getCounter(Temperature.MALFORMED).increment(1);
      } else if (parser.isMissingTemperature()) {
        context.getCounter(Temperature.MISSING).increment(1);
      }
      
      // dynamic counter
      context.getCounter("TemperatureQuality", parser.getQuality()).increment(1);
    }
  }
  
  @Override
  public int run(String[] args) throws Exception {
    Job job = JobBuilder.parseInputAndOutput(this, getConf(), args);
    if (job == null) {
      return -1;
    }
    
    job.setOutputKeyClass(Text.class);
    job.setOutputValueClass(IntWritable.class);

    job.setMapperClass(MaxTemperatureMapperWithCounters.class);
    job.setCombinerClass(MaxTemperatureReducer.class);
    job.setReducerClass(MaxTemperatureReducer.class);

    return job.waitForCompletion(true) ? 0 : 1;
  }
  
  public static void main(String[] args) throws Exception {
    int exitCode = ToolRunner.run(new MaxTemperatureWithCounters(), args);
    System.exit(exitCode);
  }
}
// ^^ MaxTemperatureWithCounters