gate.creole.annic.apache.lucene.search
Class Scorer

java.lang.Object
  gate.creole.annic.apache.lucene.search.Scorer

public abstract class Scorer
extends Object

Expert: Implements scoring for a class of queries.

Field Summary

protected Searcher

searcher

Constructor Summary

protected

Scorer(Similarity similarity) Constructs a Scorer.

Method Summary

abstract int	doc() Returns the current document number.
abstract Explanation	explain(int doc) Returns an explanation of the score for doc.
Similarity	getSimilarity() Returns the Similarity implementation used by this scorer.
abstract boolean	next(Searcher searcher) Advance to the next document matching the query.
void	score(HitCollector hc, Searcher searcher) Scores all documents and passes them to a collector.
abstract float	score(Searcher searcher) Returns the score of the current document.
abstract boolean	skipTo(int target) Skips to the first match beyond the current whose document number is greater than or equal to target.

Methods inherited from class java.lang.Object

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

Field Detail

searcher

protected Searcher searcher

Constructor Detail

Scorer

protected Scorer(Similarity similarity)

Constructs a Scorer.

Method Detail

getSimilarity

public Similarity getSimilarity()

Returns the Similarity implementation used by this scorer.

score

public void score(HitCollector hc,
                  Searcher searcher)
           throws IOException

Scores all documents and passes them to a collector.

Throws:

IOException

next

public abstract boolean next(Searcher searcher)
                      throws IOException

Advance to the next document matching the query. Returns true iff there is another match.

Throws:

IOException

doc

public abstract int doc()

Returns the current document number. Initially invalid, until #next() is called the first time.

score

public abstract float score(Searcher searcher)
                     throws IOException

Returns the score of the current document. Initially invalid, until #next() is called the first time.

Throws:

IOException

skipTo

public abstract boolean skipTo(int target)
                        throws IOException

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.

Throws:

IOException

explain

public abstract Explanation explain(int doc)
                             throws IOException

Returns an explanation of the score for doc.

Throws:

IOException