Bubbling up newest content in lucene search results

Question

Hi,

I am storing various articles in my lucene index. When user searches for articles which contain a specific term or phrase,I need to show all th articles (could be anywhere between 1000 to 10000 articles) but with newest articles "bubbled up" in the search results.

I believe you can bubble up a search result in Lucene using "Date field Boosting". Can someone please give me the details of how to go about this?

Thanks in advance!

Answer 1

I would implement the SortComparatorSource interface. You should write a new ScoreDocComparator, whose compare() function compares two dates. Then you will need to sort your searches using the new sorter. This advice is taken from chapter 6 of Lucene in Action.

Answer 2

You can use the setBoost method to set the "boost" for a particular document in the index at index time. Since the default boost value is 1.0, setting a value less than 1.0 will make the document "less relevant" in search results. By tying the boost value of a document to its age (lower boost the older the document gets), you can make newer content seem more relevant in search results.

Note in the documentation for setBoost that the boost value set at indexing time is not available for retrieved documents (boost works, you just can't read the value back at retrieval time to see if you applied the correct value at index time).