On Wed, Jun 17, 2009 at 12:26 PM, Chuck Lam <chuck....@gmail.com> wrote:
> an alternative is to create a new WritableComparator and then set it
> in the JobConf object with the method setOutputKeyComparatorClass().
> You can use IntWritable.Comparator as a start.
The important part of that is to define a RawComparator for your key class
and call JobConf.setOutputKeyComparatorClass with it.So if you wanted to
invert the default sort order of IntWritable keys, you could:
public class InvertedIntWritableComparator extends IntWritable.Comparator {
public int compare(byte[] b1, int s1, int l1,
byte[] b2, int s2, int l2) {
return -1 * super.compare(b1,s1,l1,b2,s2,l2);
}
}
then
job.setOutputKeyComparatorClass(InvertedIntWritableComparator.class);
-- Owen
