org.apache.lucene.search
Class Scorer

java.lang.Object
  extended byorg.apache.lucene.search.Scorer

public abstract class Scorer
extends java.lang.Object

Expert: Implements scoring for a class of queries.


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()
          Advance to the next document matching the query.
abstract  float score()
          Returns the score of the current document.
 void score(HitCollector hc)
          Scores all documents and passes them to a collector.
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
 

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)
           throws java.io.IOException
Scores all documents and passes them to a collector.

Throws:
java.io.IOException

next

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

Throws:
java.io.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()
                     throws java.io.IOException
Returns the score of the current document. Initially invalid, until next() is called the first time.

Throws:
java.io.IOException

skipTo

public abstract boolean skipTo(int target)
                        throws java.io.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:
java.io.IOException

explain

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

Throws:
java.io.IOException


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