CODEWITHSUNDEEP
javaluceneinformation-retrieval
yannisf
yannisf

Reputation: 6136

Boost fresh documents with Lucene

Does Lucene provide a means to boost fresh documents?

For example suppose that the Lucene document includes a date field. Is it possible, without having the user to alter her query anyhow, to present the most recent documents with a higher score?

I do not want to resort to a coarse "sort by date" solution as it will completely cancel the scoring algorithm.

Upvotes: 6

Views: 1635

Answers (2)

Xodarap
Xodarap

Reputation: 11849

You can see Lucene in Action. In the second edition, pg. 187 they give a way to do it. Basically, you will want to write your own query which extends CustomScoreQuery, and adds a boost.

Upvotes: 6

rfeak
rfeak

Reputation: 8214

Use Document.setBoost(float value) when putting documents into the index.

You can either constantly re-adjust the value on existing documents, OR have a float value that increments with date, so that you only need to apply it to the time that documents are inserted.

For example, start with a boost value of 0 for day 1 documents. Each day, increment the boost by 1. It's a float value, incrementing by 365 each year will last a long time.

You may have to experiment with the strength of the boost to get the effect you want.

Upvotes: 3

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