> I am using Lucene 4.0.0, trying to put together a CustomQuery and a > Collector, and have a problem with the calculation of scores. > > My context is as follows. I have a big BooleanQuery which works fine, but I > also want to calculate some statistics during the search (i.e. > perform aggregation operations). To do so, I have tried to pass a custom > Collector to the searcher, in charge of retrieving data from the matched > documents (using FieldCache), and performing the appropriate calculations. > The whole thing works fine, the calculations seem to be done properly (I > have yet to test more accurately) : > > --- > IndexSearcher searcher = new IndexSearcher(reader); > searcher.search(query, collector); > --- > > Now, my Collector also collects a sample of the matched documents, in order > to display them. These documents are collected one after the other, at each > call of the collect() method, until the sample is complete. What I would like > is > to have the documents sorted by their score, and I also would like to > calculate the score myself. In other words, I want to make a sample of the > "best" documents, while still calculating statistics for all matched > documents.
The best way to do this ist o wrap the standard Lucene TopScoreDocCollector by your own collector (passing all calls to the collector also down to the top-docs collector). Then you don't have to take care of sorting the results, you collector just does statistics. > I am confused about how to do that. I have created a CustomQuery, > wrapping the source BooleanQuery, using a CustomScoreProvider. > However, when I execute the search upon this query, with the collector, my > log shows that the CustomScoreProvider is properly instantiated, but that > the customScore() method is never called. > Interestingly, if I execute the custom query without the collector, retrieving > some TopDocs object, then the customScore() is called. If the collector does not use the score it is not calculated, so the provider is not called. > What can I do? So far, my collector does not make use of the Scorer passed > to the setScorer() method - should I use it? I have tried the simple > scorer.score() call in the collector setScorer() method, resulting in the > customScore() method being called, but with no docID. It gets the doc id, for sure. > Thank you in advance for your insight. > > Kind regards, > Yep. > > --------------------------------------------------------------------- > To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org > For additional commands, e-mail: java-user-h...@lucene.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org For additional commands, e-mail: java-user-h...@lucene.apache.org
