Hi

Not sure if this is the right place to ask this question...so apologies if i've got the wrong place.

I was wondering whether any one out there knows how to build taxonomy trees for example something like the below:

Region [274]
South Asia [125]
Bangladesh [23]
India [50]


I have seen commercial tools that can develop taxonomy trees (Verity) but I haven't seen any open source tools...not sure if you can do it with Lucene.

I was wondering if there is any scope to do something like this with Hibernate Search.

P.S. Looking forward to Hibernate Search In Action!

Cheers

Hi,

I think what you are after is also known as faceted search even though there are differences in these two concepts. Either way, you can implement this kind of functionality with Lucene. In fact Solr - Apaches open source enterprise search server - is build on Lucene and offered faceted searches. That does not mean though that you cannot do this type of functionality with Hibernate Search. In fact I have done something like this in my previous project. You will basically have to write some sort of home grown facet search.

There is a Jira issue regarding faceted search - http://opensource.atlassian.com/projects/hibernate/browse/HSEARCH-132 - but I believe it was decided that faceted search is not so relevant for Hibernate Search and a 'MoreLikeThis' functionality is more important.

Hope this helps.

--Hardy

Hi there

Thanks for your reply. I want to use Hibernate Search for developing the search part of the project. Is it possible if you perhaps give me some pointers on how to develop a facet search? I will in the mean time look at Lucene.


Thanks

Hi,

one of of doing this would be to utilize Hibernate Search's filter capabilties - http://www.hibernate.org/hib_docs/search/reference/en/html_single/#d0e1982. One could eg cache the hits per categories in a list of BitSets. Then at query time you can intersect the category BitSets with the search result BitSet. Depending on how often you update the index you would have to update the caches at certain times. This all depends really on the exact use case.

There are of course other approaches to this problem. Have a look at the Lucene mailing lists.

--Hardy

Is it possible you could reconsider adding facet functionality in hibernate-search. Or at least give some examples how to do it easy?
I found it quite a nice feature of Solr. Very nice for taxonomy , auto-complete etc.

Hi,

I am planning to pick this up again soon. As soon as I have some time. I thought about taking some ideas from here - http://sujitpal.blogspot.com/2007/04/lu ... -with.html
Maybe we can extend FulltextQuery to take some sort of FacetCounter object. Not really sure yet about the details.

--Hardy

Would it be possible just to integrate Solr api for facets? They implemented it quite nice. (functional and performance wise)

Solr and Hibernate Search are really two different things with different strengths and weaknesses. Whatever we do needs to fit into the Hibernate Search way of doing things.
This said, feel free to elaborate on how you think the faceted search API should look like.

--Hardy

Hi Hardy

I did something based on the blog with Hibernate Search, I'd be happy to share this with you. We've got our next search requirements through and facet search is on the agenda. It would be nice to have some sort of API integrated with Hibernate Search. Just a thought.


Cheers
Amin

Hi Amin,

I would love to discuss what you came up with. You can post your idea here or send something to hibernate-dev or directly to me.

--Hardy