org.apache.lucene.search

Class BulkScorer

java.lang.Object

org.apache.lucene.search.BulkScorer

Direct Known Subclasses:

ConstantScoreQuery.ConstantBulkScorer, Weight.DefaultBulkScorer

public abstract class BulkScorer
extends Object

This class is used to score a range of documents at once, and is returned by Weight.bulkScorer(org.apache.lucene.index.LeafReaderContext, org.apache.lucene.util.Bits). Only queries that have a more optimized means of scoring across a range of documents need to override this. Otherwise, a default implementation is wrapped around the Scorer returned by Weight.scorer(org.apache.lucene.index.LeafReaderContext, org.apache.lucene.util.Bits).

Constructor Summary

Constructors

Constructor and Description
BulkScorer()

Method Summary

Methods

Modifier and Type	Method and Description
abstract long	cost() Same as DocIdSetIterator.cost() for bulk scorers.
void	score(LeafCollector collector) Scores and collects all matching documents.
abstract int	score(LeafCollector collector, int min, int max) Collects matching documents in a range and return an estimation of the next matching document which is on or after max.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

BulkScorer

public BulkScorer()

Method Detail

score

public void score(LeafCollector collector)
           throws IOException

Scores and collects all matching documents.

Parameters:

collector - The collector to which all matching documents are passed.

Throws:

IOException

score

public abstract int score(LeafCollector collector,
        int min,
        int max)
                   throws IOException

Collects matching documents in a range and return an estimation of the next matching document which is on or after max.

The return value must be:

• >= max,
• DocIdSetIterator.NO_MORE_DOCS if there are no more matches,
• <= the first matching document that is >= max otherwise.

min is the minimum document to be considered for matching. All documents strictly before this value must be ignored.

Although max would be a legal return value for this method, higher values might help callers skip more efficiently over non-matching portions of the docID space.

For instance, a Scorer-based implementation could look like below:

 private final Scorer scorer; // set via constructor

 public int score(LeafCollector collector, int min, int max) throws IOException {
   collector.setScorer(scorer);
   int doc = scorer.docID();
   if (doc < min) {
     doc = scorer.advance(min);
   }
   while (doc < max) {
     collector.collect(doc);
     doc = scorer.nextDoc();
   }
   return doc;
 }
 

Parameters:

collector - The collector to which all matching documents are passed.

min - Score starting at, including, this document

max - Score up to, but not including, this doc

Returns:

an under-estimation of the next matching doc after max

Throws:

IOException

cost

public abstract long cost()

Same as DocIdSetIterator.cost() for bulk scorers.