sorting search results

[Doug Cutting]

Currently query filters generate a Lucene Query.  But Lucene's search 
methods have other parameters besides a query.  In particular, these can 
also be passed a Filter and a Sort.  In part as a work-around, Nutch 
automatically converts Lucene query clauses with zero boost into 
filters.  But there is currently no way to generate sorted results using 
Nutch's search API.

To remedy this I propose that the QueryFilter API be changed to 
something like:

public class SearchParameters {
  public BooleanQuery getQuery();
  public void setQuery(BooleanQuery clauses);
  public Filter getFilter();
  public void setFilter(Filter filter);
  public Sort getSort();
  public void getSort(Sort sort);
}
public interface QueryFilter {
  SearchParameters filter(Query input, SearchParameters output)
    throws QueryException;
}
If no one objects I will make this change and update all QueryFilters in 
SVN.  Then I will add a SortQueryFilter that permits clauses like 
"sort:date", and a DateRangeQueryFilter that uses Lucene's RangeFilter 
(generally much more efficient than a RangeQuery).

Thoughts?
Doug