Andrzej Bialecki wrote:
I'll test it soon - one comment, though. Currently you use a subclass of
RuntimeException to stop the collecting. I think we should come up with
a better mechanism - throwing exceptions is too costly.
I thought about this, but I could not see a simple way to achieve it.
And one exception thrown per query is not very expensive. But it is bad
style. Sigh.
Perhaps the
HitCollector.collect() method should return a boolean to signal whether
the searcher should continue working.
We don't really want a HitCollector in this case: we want a TopDocs. So
the patch I made is required: we need to extend the HitCollector that
implements TopDocs-based searching.
Long-term, to avoid the 'throw', we'd need to also:
1. Change:
TopDocs Searchable.search(Query, Filter, int numHits)
to:
TopDocs Searchable.search(Query, Filter, int numHits, maxTotalHits)
2. Add, for back-compatibility:
TopDocs Searcher.search(Query, Filter, int numHits) {
return search(query, filter, numHits, Integer.MAX_VALUE);
}
3. Add a new method:
/** Return false to stop hit processing. */
boolean HitCollector.processHit(int doc, float score) {
collect(doc, score); // for back-compatibility
return true;
}
Then change all calls to HitCollector.collect to instead call this,
and deprecate HitCollector.collect.
I think that would do it. But is it worth it?
In the past I've frequently wanted to be able to extend TopDocs-based
searching, so I think the Lucene patch I've constructed so far is
generally useful.
Doug
