org.apache.lucene.search

Class Scorer

public abstract class Scorer extends Object

Expert: Implements scoring for a class of queries.
Constructor Summary
protected Scorer(Similarity similarity)
Constructs a Scorer.
Method Summary
abstract intdoc()
Returns the current document number.
abstract Explanationexplain(int doc)
Returns an explanation of the score for doc.
SimilaritygetSimilarity()
Returns the Similarity implementation used by this scorer.
abstract booleannext()
Advance to the next document matching the query.
voidscore(HitCollector hc)
Scores all documents and passes them to a collector.
abstract floatscore()
Returns the score of the current document.
abstract booleanskipTo(int target)
Skips to the first match beyond the current whose document number is greater than or equal to target.

Constructor Detail

Scorer

protected Scorer(Similarity similarity)
Constructs a Scorer.

Method Detail

doc

public abstract int doc()
Returns the current document number. Initially invalid, until {@link #next()} is called the first time.

explain

public abstract Explanation explain(int doc)
Returns an explanation of the score for doc.

getSimilarity

public Similarity getSimilarity()
Returns the Similarity implementation used by this scorer.

next

public abstract boolean next()
Advance to the next document matching the query. Returns true iff there is another match.

score

public void score(HitCollector hc)
Scores all documents and passes them to a collector.

score

public abstract float score()
Returns the score of the current document. Initially invalid, until {@link #next()} is called the first time.

skipTo

public abstract boolean skipTo(int target)
Skips to the first match beyond the current whose document number is greater than or equal to target.

Returns true iff there is such a match.

Behaves as if written:

   boolean skipTo(int target) {
     do {
       if (!next())
 	     return false;
     } while (target > doc());
     return true;
   }
 
Most implementations are considerably more efficient than that.
Copyright © 2000-2007 Apache Software Foundation. All Rights Reserved.