org.apache.lucene.search.suggest.document

Class CompletionWeight

java.lang.Object

org.apache.lucene.search.Weight

org.apache.lucene.search.suggest.document.CompletionWeight

public class CompletionWeight
extends Weight

Expert: the Weight for CompletionQuery, used to score and explain these queries. Subclasses can override setNextMatch(IntsRef), boost() and context() to calculate the boost and extract the context of a matched path prefix.

Nested Class Summary

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

Weight.DefaultBulkScorer

Field Summary

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

parentQuery

Constructor Summary

Constructors

Constructor and Description
CompletionWeight(CompletionQuery query, Automaton automaton) Creates a weight for query with an automaton, using the reader for index stats

Method Summary

Modifier and Type	Method and Description
protected float	boost() Returns the boost of the partial path set by setNextMatch(IntsRef)
BulkScorer	bulkScorer(LeafReaderContext context) Optional method, to return a BulkScorer to score the query and send hits to a Collector.
protected CharSequence	context() Returns the context of the partial path set by setNextMatch(IntsRef)
Explanation	explain(LeafReaderContext context, int doc) An explanation of the score computation for the named document.
void	extractTerms(Set<Term> terms) Expert: adds all terms occurring in this query to the terms set.
Automaton	getAutomaton() Returns the automaton specified by the CompletionQuery
float	getValueForNormalization() The value for normalization of contained query clauses (e.g.
void	normalize(float norm, float topLevelBoost) Assigns the query normalization factor and boost from parent queries to this.
Scorer	scorer(LeafReaderContext context) Returns a Scorer which can iterate in order over all matching documents and assign them a score.
protected void	setNextMatch(IntsRef pathPrefix) Set for every partial path in the index that matched the query automaton.

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

getQuery

Methods inherited from class java.lang.Object

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

Constructor Detail

CompletionWeight

public CompletionWeight(CompletionQuery query,
                        Automaton automaton)
                 throws IOException

Creates a weight for query with an automaton, using the reader for index stats

Throws:

IOException

Method Detail

getAutomaton

public Automaton getAutomaton()

Returns the automaton specified by the CompletionQuery

Returns:

query automaton

bulkScorer

public BulkScorer bulkScorer(LeafReaderContext context)
                      throws IOException

Description copied from class: Weight

Optional method, to return a BulkScorer to score the query and send hits to a Collector. Only queries that have a different top-level approach need to override this; the default implementation pulls a normal Scorer and iterates and collects the resulting hits which are not marked as deleted.

Overrides:

bulkScorer in class Weight

Parameters:

context - the LeafReaderContext for which to return the Scorer.

Returns:

a BulkScorer which scores documents and passes them to a collector.

Throws:

IOException - if there is a low-level I/O error

setNextMatch

protected void setNextMatch(IntsRef pathPrefix)

Set for every partial path in the index that matched the query automaton. Subclasses should override boost() and context() to return an appropriate value with respect to the current pathPrefix.

Parameters:

pathPrefix - the prefix of a matched path

boost

protected float boost()

Returns the boost of the partial path set by setNextMatch(IntsRef)

Returns:

suggestion query-time boost

context

protected CharSequence context()

Returns the context of the partial path set by setNextMatch(IntsRef)

Returns:

suggestion context

scorer

public Scorer scorer(LeafReaderContext context)
              throws IOException

Description copied from class: Weight

Returns a Scorer which can iterate in order over all matching documents and assign them a score.

NOTE: null can be returned if no documents will be scored by this query.

NOTE: The returned Scorer does not have LeafReader.getLiveDocs() applied, they need to be checked on top.

Specified by:

scorer in class Weight

Parameters:

context - the LeafReaderContext for which to return the Scorer.

Returns:

a Scorer which scores documents in/out-of order.

Throws:

IOException - if there is a low-level I/O error

extractTerms

public void extractTerms(Set<Term> terms)

Description copied from class: Weight

Expert: adds all terms occurring in this query to the terms set. If the Weight was created with needsScores == true then this method will only extract terms which are used for scoring, otherwise it will extract all terms which are used for matching.

Specified by:

extractTerms in class Weight

explain

public Explanation explain(LeafReaderContext context,
                           int doc)
                    throws IOException

Description copied from class: Weight

An explanation of the score computation for the named document.

Specified by:

explain in class Weight

Parameters:

context - the readers context to create the Explanation for.

doc - the document's id relative to the given context's reader

Returns:

an Explanation for the score

Throws:

IOException - if an IOException occurs

getValueForNormalization

public float getValueForNormalization()
                               throws IOException

Description copied from class: Weight

The value for normalization of contained query clauses (e.g. sum of squared weights).

Specified by:

getValueForNormalization in class Weight

Throws:

IOException

normalize

public void normalize(float norm,
                      float topLevelBoost)

Description copied from class: Weight

Assigns the query normalization factor and boost from parent queries to this.

Specified by:

normalize in class Weight