How can I run all as one source code? import java.io.IOException; import org.apa

Question

How can I run all as one source code?

import java.io.IOException;

import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;

public class MaxTemperatureMapper
extends Mapper<LongWritable, Text, Text, IntWritable> {

private static final int MISSING = 9999;
  
@Override
public void map(LongWritable key, Text value, Context context)
throws IOException, InterruptedException {
  
String line = value.toString();
String year = line.substring(15, 19);
int airTemperature;
if (line.charAt(87) == '+') { // parseInt doesn't like leading plus signs
airTemperature = Integer.parseInt(line.substring(88, 92));
} else {
airTemperature = Integer.parseInt(line.substring(87, 92));
}
String quality = line.substring(92, 93);
if (airTemperature != MISSING && quality.matches("[01459]")) {
context.write(new Text(year), new IntWritable(airTemperature));
}
}
}

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.fs.Path;

import org.apache.hadoop.io.IntWritable;

import org.apache.hadoop.io.Text;

import org.apache.hadoop.mapreduce.Job;

import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;

import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;

public class MaxTemperature {

public static void main(String[] args) throws Exception {

if (args.length != 2) {

System.err.println("Usage: MaxTemperature <input path> <output path>");

System.exit(-1);

}

Configuration conf = new Configuration();

Job job = Job.getInstance(conf, "Max temperature");

job.setJarByClass(MaxTemperature.class);

job.setMapperClass(MaxTemperatureMapper.class);

job.setReducerClass(MaxTemperatureReducer.class);

job.setOutputKeyClass(Text.class);

job.setOutputValueClass(IntWritable.class);

FileInputFormat.setInputDirRecursive(job, true);

FileInputFormat.addInputPath(job, new Path(args[0]));

FileOutputFormat.setOutputPath(job, new Path(args[1]));

System.exit(job.waitForCompletion(true) ? 0 : 1);

}

}

// ^^ MaxTemperature

import java.io.IOException;

import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Reducer;

public class MaxTemperatureReducer
extends Reducer<Text, IntWritable, Text, IntWritable> {
  
@Override
public void reduce(Text key, Iterable<IntWritable> values,
Context context)
throws IOException, InterruptedException {
  
int maxValue = Integer.MIN_VALUE;
for (IntWritable value : values) {
maxValue = Math.max(maxValue, value.get());
}
context.write(key, new IntWritable(maxValue));
}
}

Explanation / Answer

-------------------------MaxTemperature.java-------------------------

import java.io.IOException;

import org.apache.hadoop.io.IntWritable;

import org.apache.hadoop.io.LongWritable;

import org.apache.hadoop.io.Text;

import org.apache.hadoop.mapreduce.Mapper;

import org.apache.hadoop.mapreduce.Reducer;

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.fs.Path;

import org.apache.hadoop.io.IntWritable;

import org.apache.hadoop.io.Text;

import org.apache.hadoop.mapreduce.Job;

import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;

import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;

class MaxTemperatureMapper extends Mapper<LongWritable, Text, Text, IntWritable> {

private static final int MISSING = 9999;

@Override

public void map(LongWritable key, Text value, Context context)

      throws IOException, InterruptedException {

    String line = value.toString();

    String year = line.substring(15, 19);

    int airTemperature;

    if (line.charAt(87) == '+') { // parseInt doesn't like leading plus signs

      airTemperature = Integer.parseInt(line.substring(88, 92));

    } else {

      airTemperature = Integer.parseInt(line.substring(87, 92));

    }

    String quality = line.substring(92, 93);

    if (airTemperature != MISSING && quality.matches("[01459]")) {

      context.write(new Text(year), new IntWritable(airTemperature));

    }

}

}

// ^^ MaxTemperature

class MaxTemperatureReducer extends Reducer<Text, IntWritable, Text, IntWritable> {

@Override

public void reduce(Text key, Iterable<IntWritable> values,

      Context context)

      throws IOException, InterruptedException {

    int maxValue = Integer.MIN_VALUE;

    for (IntWritable value : values) {

      maxValue = Math.max(maxValue, value.get());

    }

    context.write(key, new IntWritable(maxValue));

  }

}

// as this class has the main method, so make this class public and other classes not

// declared as public

public class MaxTemperature {

public static void main(String[] args) throws Exception {

    if (args.length != 2) {

      System.err.println("Usage: MaxTemperature <input path> <output path>");

      System.exit(-1);

    }

    Configuration conf = new Configuration();

Job job = Job.getInstance(conf, "Max temperature");

    job.setJarByClass(MaxTemperature.class);

    job.setMapperClass(MaxTemperatureMapper.class);

    job.setReducerClass(MaxTemperatureReducer.class);

    job.setOutputKeyClass(Text.class);

    job.setOutputValueClass(IntWritable.class);

FileInputFormat.setInputDirRecursive(job, true);

    FileInputFormat.addInputPath(job, new Path(args[0]));

    FileOutputFormat.setOutputPath(job, new Path(args[1]));

    System.exit(job.waitForCompletion(true) ? 0 : 1);

}

}

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