Question

I have a file containing a String, then a space and then a number on every line.

Example:

Line1: Word 2
Line2 : Word1 8
Line3: Word2 1

I need to sort the number in descending order and then put the result in a file assigning a rank to the numbers. So my output should be a file containing the following format:

Line1: Word1 8 1
Line2: Word  2 2
Line3: Word2 1 3

Does anyone has an idea, how can I do it in Hadoop?
I am using java with Hadoop.

Answer 1

I devised the solution to this problem. It was simple actually.

For sorting by value you need to use

setOutputValueGroupingComparator(Class)

For sorting in decreasing order you need to use setSortComparatorClass(LongWritable.DecreasingComparator.class);

For ranking you need to use
Counter class, getCounter and increment function.