Terrier Core

Currently, QueryExpansion.java is responsible for the full QE process - selecting documents, accessing direct file, adding terms to ExpansionTerms, and re-running the query.

I propose that we have an interface which selects the feedback documents for a given query, thus allowing Psuedo-Relevance Feedback and normal Relevance Feedback (as well as mixes - only using some of the documents in the feedback).

interface FeedbackSelector
{
 public FeedbackDocument[] getFeedbackDocuments(Request r);
}

class FeedbackDocument
{
 int docid;
 int rank;
 double score;
 public int getDocid() {return docid;}
 public int getRank() {return rank;}
 public double getScore() {return score;}
}

First patch for this issue. Works and is ready for review.

Many thanks Craig. Good stuff.

I also asked Ben to test.

patch tested ok on WT10G

Thanks for testing Ben. I have committed to trunk.