PageRank-Algorithm-using-MapReduce/PageRankDriver.java at master · BigWheel92/PageRank-Algorithm-using-MapReduce · GitHub

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package bigdata;

import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.DoubleWritable;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.ObjectWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;


public class PageRankDriver extends Configured implements Tool {

	public static double BETA=0.8;

	public static enum Counter {

		totalNodes,
		sumOfPageRanks;
	}

  @Override
  public int run(String[] args) throws Exception {


    if (args.length != 2) {
      System.out.printf("Usage: " + this.getClass().getName() + " <input dir> <output dir>\n");
      return -1;
    }

    int iterationCount=0;


while (true)
{
	 System.out.println("Running Map Reduce Job!!!!!!");


	 ///////////////////////////First Map Reduce Job Which calculates S///////////////////////////////////////

	    Job job_s = Job.getInstance(getConf());
	    job_s.setJarByClass(PageRankDriver.class);
	    job_s.setJobName("S_Calculation");


	    FileSystem fs = FileSystem.get(new Configuration());
	   fs.delete(new Path("/Temp"), true);
	   fs.delete(new Path(args[1]), true);

	    FileInputFormat.setInputPaths(job_s, new Path(args[0]));
	    FileOutputFormat.setOutputPath(job_s, new Path("/Temp"));


	    job_s.setReducerClass(S_Calculation_Reducer.class);
	    job_s.setMapperClass(S_Calculation_Mapper.class);


		job_s.setMapOutputKeyClass(IntWritable.class);
		job_s.setMapOutputValueClass(DoubleWritable.class);

		/*
		 * Set the key output class for the job_s
		 */
	    job_s.setOutputKeyClass(DoubleWritable.class);

	    /*
	     * Set the value output class for the job_s
	     */
	    job_s.setOutputValueClass(NullWritable.class);
	    job_s.setNumReduceTasks(1);
	    job_s.waitForCompletion(true); //the first job calculates S.

	  double sumOfPageRanks= (double) job_s.getCounters().findCounter(Counter.sumOfPageRanks).getValue()/ (double)10000.0; //getting sum of page ranks S from the previous job
	   System.out.println("S: "+sumOfPageRanks);


	    fs.delete(new Path("/Temp"),true);

   	    /////////////////////////Second map reduce job which calculates page rank of each node////////////////////////////////////////////////
	 Job job = Job.getInstance(getConf());
	    job.setJarByClass(PageRankDriver.class);
	    //job.setJobName("Page Rank");
	    job.getConfiguration().setDouble("sumOfPageRanks", sumOfPageRanks); //passing sum of Page ranks S.


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


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


	    job.setReducerClass(PageRankReducer.class);
	    job.setMapperClass(PageRankMapper.class);


		job.setMapOutputKeyClass(Text.class);
		job.setMapOutputValueClass(ObjectWritable.class);

		/*
		 * Set the key output class for the job
		 */
	    job.setOutputKeyClass(Text.class);

	    /*
	     * Set the value output class for the job
	     */
	    job.setOutputValueClass(Text.class);


    boolean success = job.waitForCompletion(true);


    iterationCount++;


    if (iterationCount>2)
    {


    	fs.delete(new Path(args[0]), true); //deleting folder before exiting

   	 System.out.println("Total Number of Times the Job was run= "+iterationCount);
    	System.out.println("total Nodes Processed: "+job.getCounters().findCounter(Counter.totalNodes).getValue());

   	    return (success==true ? 1: 0);
    }

    else
    {

    	fs.delete(new Path(args[0]), true);


    	fs.rename(new Path(args[1]), new Path(args[0]));
	 }

  }

  }


  public static void main(String[] args) throws Exception {
    int exitCode = ToolRunner.run(new Configuration(), new PageRankDriver(), args);
    System.exit(exitCode);
  }


}