Re: Lucene 4 - Faceted Search with Sorting

[Sanket Paranjape]

Hi Shai,

Thanks for helping out.
It worked. :)

I also want to add pagination feature. This can be done via searchAfter 
method in IndexSearcher. But, this does not have Collector (I want 
facets from this).

I think this has been done intentionally because facets would remain 
same while paginating/sorting.

So my approach to this would be following.

1. On first search call below code to get first set of results along
   with facets.
2. Save *last* ScoreDoc somewhere in the session so that it can be used
   to pagination. Also save facetCollector so as to use it later on
   pagination request to show facets.
3. On subsequent pagination requests use IndexSearcher.searchAfter
   method to get next set of results using ScoreDoc from session.
4. If user want to narrow down on facets then follow steps from 1 to 3
   using Drill-down feature.

Am I correct?

On 01-08-2013 11:33 PM, Shai Erera wrote:
Hi

You should do the following:

TopFieldCollector tfc = TopFieldCollector.create();
FacetsCollector fc = FacetsCollector.create();
searcher.search(query, MultiCollector.wrap(tfc, fc));

Basically IndexSearcher.search(..., Sort) creates TopFieldCollector
internally, so you need to create it outside and wrap both collectors with
MultiCollector.

BTW, you don't need to do new CategoryPath("CATEGORY_PATH", '/'), when the
category does not contain the delimiter.
You can use the vararg constructor which takes the path components
directly, if you have them already.

Shai


On Thu, Aug 1, 2013 at 7:46 PM, Sanket Paranjape <
sanket.paranjape.mailingl...@gmail.com> wrote:

I am trying to move from lucene 2.4 to 4.4. I had used bobo-browse for
faceting in 2.4.

I used below code (from Lucene examples) to query documents and get facets.

     List<FacetRequest> categories = new ArrayList<FacetRequest>();
     categories.add(new CountFacetRequest(new CategoryPath("CATEGORY_PATH",
'/'), 10));
     FacetSearchParams searchParams = new FacetSearchParams(categories);
     TopScoreDocCollector topScoreDocCollector =
TopScoreDocCollector.create(200, true);
     FacetsCollector facetsCollector = FacetsCollector.create(searchParams,
indexReader, taxonomyReader);
     indexSearcher.search(new MatchAllDocsQuery(),
MultiCollector.wrap(topScoreDocCollector, facetsCollector));

Above code gives me results along with facets.

Now I want to add a Sort field on document, say I want to sort by name. I
can achieve this using following

     Sort sort = new Sort(new SortField("NAME", Type.STRING));
     TopFieldDocs docs = indexSearcher.search(new MatchAllDocsQuery(), 100,
sort);

Now, how do I achieve sorting along with faceting, because there is no
method in IndexSearcher which has Collector and Sort.


I have asked this question on stackoverflow as well. (

http://stackoverflow.com/questions/17992183/lucene-4-faceted-search-with-sorting
)


Please Help !!