case_count_country_wise.java

import java.io.IOException;
import java.util.StringTokenizer;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.BooleanWritable;
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.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;

public class Covid19_1 {

  public static class TokenizerMapper
       extends Mapper<Object, Text, Text, IntWritable>{

    private final static IntWritable one = new IntWritable(1);
    private Text row = new Text();

    public void map(Object key, Text value, Context context
                    ) throws IOException, InterruptedException {
      Configuration conf = context.getConfiguration();
      String w = conf.get("world_data");
      boolean world = Boolean.parseBoolean(w);


      if(value.toString().contains("new_cases"))
        return;

      String[] covid_row = value.toString().split(",");
      String loc_val = covid_row[1];
      String[] date_val = covid_row[0].split("-");
      int year = Integer.parseInt(date_val[0]); 

      if((!world) && (loc_val.equals("World") || loc_val.equals("International")))
        return;

      else{
        if(year != 2019){
          IntWritable num_cases = new IntWritable(Integer.parseInt(covid_row[2]));
          Text loc = new Text(covid_row[1].toString());
          context.write(loc , num_cases);
        }      

      }

    }
  }

  public static class IntSumReducer
       extends Reducer<Text,IntWritable,Text,IntWritable> {
    private IntWritable result = new IntWritable();

    public void reduce(Text key, Iterable<IntWritable> values,
                       Context context
                       ) throws IOException, InterruptedException {
      int sum = 0;
      for (IntWritable val : values) {
        sum += val.get();
      }
      result.set(sum);
      context.write(key, result);
    }
  }

  public static void main(String[] args) throws Exception {
    Configuration conf = new Configuration();
    String check = args[1].toString();
    conf.set("world_data", check);
    Job job = Job.getInstance(conf, "covid 19_1");
    
    job.setJarByClass(Covid19_1.class);
    
    job.setMapperClass(TokenizerMapper.class);
    job.setCombinerClass(IntSumReducer.class);
    job.setReducerClass(IntSumReducer.class);
    job.setOutputKeyClass(Text.class);
    job.setOutputValueClass(IntWritable.class);
    FileInputFormat.addInputPath(job, new Path(args[0]));
    FileOutputFormat.setOutputPath(job, new Path(args[2]));
    
    System.exit(job.waitForCompletion(true) ? 0 : 1);
  }
}