High frequency terms in results document....

[Shouvik Bardhan]

Apologies if I have missed it in discussions prior but I looked all over. I
looked at the Luke code and it does find high frequency terms on the entire
index. I am trying to get the top N high frequency terms in the documents
returned from a search result. I came across something called
FilterIndexReader but I don't think it is part of 4.X codebase. Any pointer
is appreciated.