descendingsort.java

// Set Sort Comparator Class in the Driver code

job.setSortComparatorClass(SortFloatComparator.class);

// Write a Sort Comparator and save as "SortFloatComparator.java"

import java.io.*;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.WritableComparable;
import org.apache.hadoop.io.WritableComparator;

public class SortFloatComparator extends WritableComparator {

	//Constructor.
	 
	protected SortFloatComparator() {
		super(Text.class, true);
	}
	
	@SuppressWarnings("rawtypes")
	@Override
	public int compare(WritableComparable w1, WritableComparable w2) {
		String k1 = ((Text)w1).toString();
		String k2 = ((Text)w2).toString();
		
		return -1 * k1.compareTo(k2);
	}
}

// Mapper and Reducer Codes here...