[SOLVED] Return Only Certain Fields From Lucene Search

Return Only Certain Fields From Lucene Search

I'm using Lucene to search an index and it works fine. My only issue is that I only need one particular field of what is being returned. Can you specify to Lucene to only return a certain field in the results and not the entire document?

Solution

This is why FieldSelector class exists. You can implement a class like this

class MyFieldSelector : FieldSelector
{
    public FieldSelectorResult Accept(string fieldName)
    {
        if (fieldName == "field1") return FieldSelectorResult.LOAD_AND_BREAK;
        return FieldSelectorResult.NO_LOAD;
    }
}

and use it as indexReader.Document(docid,new MyFieldSelector());

If you are interested in loading a small field, this will prevent to load large fields which, in turn, means a speed-up in loading documents. I think you can find much more detailed info by some googling.