org.apache.lucene.search.spans

Class SpanWeight

java.lang.Object

org.apache.lucene.search.Weight

org.apache.lucene.search.spans.SpanWeight

Direct Known Subclasses:

org.apache.lucene.search.spans.SpanContainQuery.SpanContainWeight, SpanNearQuery.SpanNearWeight, SpanNotQuery.SpanNotWeight, SpanOrQuery.SpanOrWeight, SpanPositionCheckQuery.SpanPositionCheckWeight, SpanTermQuery.SpanTermWeight

public abstract class SpanWeight
extends Weight

Expert-only. Public for use by other weight implementations

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	SpanWeight.Postings Enumeration defining what postings information should be retrieved from the index for a given Spans

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

Weight.DefaultBulkScorer

Field Summary

Fields

Modifier and Type	Field and Description
protected String	field
protected Similarity	similarity
protected Similarity.SimWeight	simWeight

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

parentQuery

Constructor Summary

Constructors

Constructor and Description
SpanWeight(SpanQuery query, IndexSearcher searcher, Map<Term,TermContext> termContexts) Create a new SpanWeight

Method Summary

Methods

Modifier and Type	Method and Description
Explanation	explain(LeafReaderContext context, int doc) An explanation of the score computation for the named document.
abstract void	extractTermContexts(Map<Term,TermContext> contexts) Collect all TermContexts used by this Weight
Similarity.SimScorer	getSimScorer(LeafReaderContext context) Return a SimScorer for this context
abstract Spans	getSpans(LeafReaderContext ctx, SpanWeight.Postings requiredPostings) Expert: Return a Spans object iterating over matches from this Weight
float	getValueForNormalization() The value for normalization of contained query clauses (e.g.
void	normalize(float queryNorm, float boost) Assigns the query normalization factor and boost to this.
Scorer	scorer(LeafReaderContext context) Returns a Scorer which can iterate in order over all matching documents and assign them a score.

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

bulkScorer, extractTerms, getQuery

Methods inherited from class java.lang.Object

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

Field Detail

similarity

protected final Similarity similarity

simWeight

protected final Similarity.SimWeight simWeight

field

protected final String field

Constructor Detail

SpanWeight

public SpanWeight(SpanQuery query,
          IndexSearcher searcher,
          Map<Term,TermContext> termContexts)
           throws IOException

Create a new SpanWeight

Parameters:

query - the parent query

searcher - the IndexSearcher to query against

termContexts - a map of terms to termcontexts for use in building the similarity. May be null if scores are not required

Throws:

IOException - on error

Method Detail

extractTermContexts

public abstract void extractTermContexts(Map<Term,TermContext> contexts)

Collect all TermContexts used by this Weight

Parameters:

contexts - a map to add the TermContexts to

getSpans

public abstract Spans getSpans(LeafReaderContext ctx,
             SpanWeight.Postings requiredPostings)
                        throws IOException

Expert: Return a Spans object iterating over matches from this Weight

Parameters:

ctx - a LeafReaderContext for this Spans

requiredPostings - the postings information required

Returns:

a Spans

Throws:

IOException - on error

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 queryNorm,
             float boost)

Description copied from class: Weight

Assigns the query normalization factor and boost to this.

Specified by:

normalize in class Weight

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

getSimScorer

public Similarity.SimScorer getSimScorer(LeafReaderContext context)
                                  throws IOException

Return a SimScorer for this context

Parameters:

context - the LeafReaderContext

Returns:

a SimWeight

Throws:

IOException - on error

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