abstract public  void collect(int doc,
    float score)
Called once for every document matching a query, with the document
number and its raw score.

If, for example, an application wished to collect all of the hits for a
query in a BitSet, then it might:
Searcher searcher = new IndexSearcher(indexReader);
final BitSet bits = new BitSet(indexReader.maxDoc());
searcher.search(query, new HitCollector() {
public void collect(int doc, float score) {
bits.set(doc);
}
});


Note: This is called in an inner search loop. For good search
performance, implementations of this method should not call
Searcher#doc(int)  or
org.apache.lucene.index.IndexReader#document(int)  on every
document number encountered. Doing so can slow searches by an order
of magnitude or more.
Note: The score passed to this method is a raw score.
In other words, the score will not necessarily be a float whose value is
between 0 and 1.