org.apache.lucene.search

Class MinShouldMatchSumScorer

java.lang.Object

org.apache.lucene.search.Scorer

org.apache.lucene.search.MinShouldMatchSumScorer

final class MinShouldMatchSumScorer
extends Scorer

A Scorer for BooleanQuery when minShouldMatch is between 2 and the total number of clauses. This implementation keeps sub scorers in 3 different places: - lead: a linked list of scorer that are positioned on the desired doc ID - tail: a heap that contains at most minShouldMatch - 1 scorers that are behind the desired doc ID. These scorers are ordered by cost so that we can advance the least costly ones first. - head: a heap that contains scorers which are beyond the desired doc ID, ordered by doc ID in order to move quickly to the next candidate. Finding the next match consists of first setting the desired doc ID to the least entry in 'head' and then advance 'tail' until there is a match.

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
(package private) java.util.Collection<Scorer.ChildScorer>	childScorers
(package private) float[]	coord
(package private) long	cost
(package private) int	doc
(package private) int	freq
(package private) DisiPriorityQueue	head
(package private) DisiWrapper	lead
(package private) int	minShouldMatch
(package private) DisiWrapper[]	tail
(package private) int	tailSize

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

weight

Constructor Summary

Constructors

Constructor and Description
MinShouldMatchSumScorer(Weight weight, java.util.Collection<Scorer> scorers, int minShouldMatch, float[] coord)

Method Summary

Modifier and Type	Method and Description
private void	addLead(DisiWrapper lead)
private void	addTail(DisiWrapper s) Add an entry to 'tail'.
private void	advanceTail()
private void	advanceTail(DisiWrapper top)
private static long	cost(java.util.Collection<Scorer> scorers, int minShouldMatch)
int	docID() Returns the doc ID that is currently being scored.
private int	doNext() Advance tail to the lead until there is a match.
private static void	downHeapCost(DisiWrapper[] heap, int size)
int	freq() Returns the freq of this Scorer on the current document
java.util.Collection<Scorer.ChildScorer>	getChildren() Returns child sub-scorers
private DisiWrapper	insertTailWithOverFlow(DisiWrapper s) Insert an entry in 'tail' and evict the least-costly scorer if full.
DocIdSetIterator	iterator() Return a DocIdSetIterator over matching documents.
private DisiWrapper	popTail() Pop the least-costly scorer from 'tail'.
private void	pushBackLeads()
float	score() Returns the score of the current document matching the query.
private void	setDocAndFreq() Reinitializes head, freq and doc from 'head'
private void	updateFreq() Advance all entries from the tail to know about all matches on the current doc.
private static void	upHeapCost(DisiWrapper[] heap, int i) Heap helpers

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

getWeight, twoPhaseIterator

Methods inherited from class java.lang.Object

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

Field Detail

minShouldMatch

final int minShouldMatch

coord

final float[] coord

lead

DisiWrapper lead

doc

int doc

freq

int freq

head

final DisiPriorityQueue head

tail

final DisiWrapper[] tail

tailSize

int tailSize

childScorers

final java.util.Collection<Scorer.ChildScorer> childScorers

cost

final long cost

Constructor Detail

MinShouldMatchSumScorer

MinShouldMatchSumScorer(Weight weight,
                        java.util.Collection<Scorer> scorers,
                        int minShouldMatch,
                        float[] coord)

Method Detail

cost

private static long cost(java.util.Collection<Scorer> scorers,
                         int minShouldMatch)

getChildren

public final java.util.Collection<Scorer.ChildScorer> getChildren()

Description copied from class: Scorer

Returns child sub-scorers

Overrides:

getChildren in class Scorer

iterator

public DocIdSetIterator iterator()

Description copied from class: Scorer

Return a DocIdSetIterator over matching documents. The returned iterator will either be positioned on -1 if no documents have been scored yet, DocIdSetIterator.NO_MORE_DOCS if all documents have been scored already, or the last document id that has been scored otherwise. The returned iterator is a view: calling this method several times will return iterators that have the same state.

Specified by:

iterator in class Scorer

addLead

private void addLead(DisiWrapper lead)

pushBackLeads

private void pushBackLeads()
                    throws java.io.IOException

Throws:

java.io.IOException

advanceTail

private void advanceTail(DisiWrapper top)
                  throws java.io.IOException

Throws:

java.io.IOException

advanceTail

private void advanceTail()
                  throws java.io.IOException

Throws:

java.io.IOException

setDocAndFreq

private void setDocAndFreq()

Reinitializes head, freq and doc from 'head'

doNext

private int doNext()
            throws java.io.IOException

Advance tail to the lead until there is a match.

Throws:

java.io.IOException

updateFreq

private void updateFreq()
                 throws java.io.IOException

Advance all entries from the tail to know about all matches on the current doc.

Throws:

java.io.IOException

freq

public int freq()
         throws java.io.IOException

Description copied from class: Scorer

Returns the freq of this Scorer on the current document

Specified by:

freq in class Scorer

Throws:

java.io.IOException

score

public float score()
            throws java.io.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 on the Scorer.iterator() the first time, or when called from within LeafCollector.collect(int).

Specified by:

score in class Scorer

Throws:

java.io.IOException

docID

public int docID()

Description copied from class: Scorer

Returns the doc ID that is currently being scored. This will return -1 if the Scorer.iterator() is not positioned or DocIdSetIterator.NO_MORE_DOCS if it has been entirely consumed.

Specified by:

docID in class Scorer

See Also:

DocIdSetIterator.docID()

insertTailWithOverFlow

private DisiWrapper insertTailWithOverFlow(DisiWrapper s)

Insert an entry in 'tail' and evict the least-costly scorer if full.

addTail

private void addTail(DisiWrapper s)

Add an entry to 'tail'. Fails if over capacity.

popTail

private DisiWrapper popTail()

Pop the least-costly scorer from 'tail'.

upHeapCost

private static void upHeapCost(DisiWrapper[] heap,
                               int i)

Heap helpers

downHeapCost

private static void downHeapCost(DisiWrapper[] heap,
                                 int size)