org.apache.lucene.search.spans

Class SpanScorer

java.lang.Object

org.apache.lucene.search.DocIdSetIterator

org.apache.lucene.search.Scorer

org.apache.lucene.search.spans.SpanScorer

Direct Known Subclasses:

PayloadNearQuery.PayloadNearSpanScorer

public class SpanScorer
extends Scorer

Public for extension only.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.lucene.search.Scorer

Scorer.ChildScorer

Field Summary

Fields

Modifier and Type	Field and Description
protected Similarity.SimScorer	docScorer similarity used in default score impl
protected float	freq accumulated sloppy freq (computed in setFreqCurrentDoc)
protected int	numMatches number of matches (computed in setFreqCurrentDoc)
protected Spans	spans underlying spans we are scoring from

Fields inherited from class org.apache.lucene.search.Scorer

weight

Fields inherited from class org.apache.lucene.search.DocIdSetIterator

NO_MORE_DOCS

Constructor Summary

Constructors

Constructor and Description
SpanScorer(Spans spans, SpanWeight weight, Similarity.SimScorer docScorer) Creates a new SpanScorer

Method Summary

Methods

Modifier and Type	Method and Description
int	advance(int target) Advances to the first beyond the current whose document number is greater than or equal to target, and returns the document number itself.
TwoPhaseIterator	asTwoPhaseIterator() Optional method: Return a TwoPhaseIterator view of this Scorer.
long	cost() Returns the estimated cost of this DocIdSetIterator.
int	docID() Returns the following: -1 if DocIdSetIterator.nextDoc() or DocIdSetIterator.advance(int) were not called yet.
protected void	doCurrentSpans() Called each time the scorer's Spans is advanced during frequency calculation
protected void	doStartCurrentDoc() Called before the current doc's frequency is calculated
int	freq() Returns the freq of this Scorer on the current document
int	nextDoc() Advances to the next document in the set and returns the doc it is currently on, or DocIdSetIterator.NO_MORE_DOCS if there are no more docs in the set. NOTE: after the iterator has exhausted you should not call this method, as it may result in unpredicted behavior.
float	score() Returns the score of the current document matching the query.
protected float	scoreCurrentDoc() Score the current doc.
protected void	setFreqCurrentDoc() Sets freq and numMatches for the current document.
float	sloppyFreq() Returns the intermediate "sloppy freq" adjusted for edit distance

Methods inherited from class org.apache.lucene.search.Scorer

getChildren, getWeight

Methods inherited from class org.apache.lucene.search.DocIdSetIterator

all, empty, slowAdvance

Methods inherited from class java.lang.Object

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

Field Detail

spans

protected final Spans spans

underlying spans we are scoring from

docScorer

protected final Similarity.SimScorer docScorer

similarity used in default score impl

freq

protected float freq

accumulated sloppy freq (computed in setFreqCurrentDoc)

numMatches

protected int numMatches

number of matches (computed in setFreqCurrentDoc)

Constructor Detail

SpanScorer

public SpanScorer(Spans spans,
          SpanWeight weight,
          Similarity.SimScorer docScorer)
           throws IOException

Creates a new SpanScorer

Throws:

IOException

NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.

Method Detail

nextDoc

public final int nextDoc()
                  throws IOException

Description copied from class: DocIdSetIterator

Advances to the next document in the set and returns the doc it is currently on, or DocIdSetIterator.NO_MORE_DOCS if there are no more docs in the set.
NOTE: after the iterator has exhausted you should not call this method, as it may result in unpredicted behavior.

Specified by:

nextDoc in class DocIdSetIterator

Throws:

IOException

advance

public final int advance(int target)
                  throws IOException

Description copied from class: DocIdSetIterator

Advances to the first beyond the current whose document number is greater than or equal to target, and returns the document number itself. Exhausts the iterator and returns DocIdSetIterator.NO_MORE_DOCS if target is greater than the highest document number in the set.

The behavior of this method is undefined when called with target ≤ current, or after the iterator has exhausted. Both cases may result in unpredicted behavior.

When target > current it behaves as if written:

 int advance(int target) {
   int doc;
   while ((doc = nextDoc()) < target) {
   }
   return doc;
 }
 

Some implementations are considerably more efficient than that.

NOTE: this method may be called with DocIdSetIterator.NO_MORE_DOCS for efficiency by some Scorers. If your implementation cannot efficiently determine that it should exhaust, it is recommended that you check for that value in each call to this method.

Specified by:

advance in class DocIdSetIterator

Throws:

IOException

setFreqCurrentDoc

protected final void setFreqCurrentDoc()
                                throws IOException

Sets freq and numMatches for the current document.

This will be called at most once per document.

Throws:

IOException

doStartCurrentDoc

protected void doStartCurrentDoc()
                          throws IOException

Called before the current doc's frequency is calculated

Throws:

IOException

doCurrentSpans

protected void doCurrentSpans()
                       throws IOException

Called each time the scorer's Spans is advanced during frequency calculation

Throws:

IOException

scoreCurrentDoc

protected float scoreCurrentDoc()
                         throws IOException

Score the current doc. The default implementation scores the doc with the similarity using the slop-adjusted freq.

Throws:

IOException

docID

public final int docID()

Description copied from class: DocIdSetIterator

Returns the following:

• -1 if DocIdSetIterator.nextDoc() or DocIdSetIterator.advance(int) were not called yet.
• DocIdSetIterator.NO_MORE_DOCS if the iterator has exhausted.
• Otherwise it should return the doc ID it is currently on.

Specified by:

docID in class DocIdSetIterator

score

public final float score()
                  throws IOException

Description copied from class: Scorer

Returns the score of the current document matching the query. Initially invalid, until DocIdSetIterator.nextDoc() or DocIdSetIterator.advance(int) is called the first time, or when called from within LeafCollector.collect(int).

Specified by:

score in class Scorer

Throws:

IOException

freq

public final int freq()
               throws IOException

Description copied from class: Scorer

Returns the freq of this Scorer on the current document

Specified by:

freq in class Scorer

Throws:

IOException

sloppyFreq

public final float sloppyFreq()
                       throws IOException

Returns the intermediate "sloppy freq" adjusted for edit distance

Throws:

IOException

NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.

cost

public final long cost()

Description copied from class: DocIdSetIterator

Returns the estimated cost of this DocIdSetIterator.

This is generally an upper bound of the number of documents this iterator might match, but may be a rough heuristic, hardcoded value, or otherwise completely inaccurate.

Specified by:

cost in class DocIdSetIterator

asTwoPhaseIterator

public final TwoPhaseIterator asTwoPhaseIterator()

Description copied from class: Scorer

Optional method: Return a TwoPhaseIterator view of this Scorer. A return value of null indicates that two-phase iteration is not supported. Note that the returned TwoPhaseIterator's approximation must advance synchronously with this iterator: advancing the approximation must advance this iterator and vice-versa. Implementing this method is typically useful on Scorers that have a high per-document overhead in order to confirm matches. The default implementation returns null.

Overrides:

asTwoPhaseIterator in class Scorer