Package org.elasticsearch.index.similarity

Class ScriptedSimilarity

java.lang.Object

org.apache.lucene.search.similarities.Similarity

org.elasticsearch.index.similarity.ScriptedSimilarity

public final class ScriptedSimilarity
extends Similarity

A Similarity implementation that allows scores to be scripted.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	ScriptedSimilarity.Doc	Statistics that are specific to a document.
static class	ScriptedSimilarity.Field	Statistics that are specific to a given field.
static class	ScriptedSimilarity.Query	Scoring factors that come from the query.
static class	ScriptedSimilarity.Term	Statistics that are specific to a given term.

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

Similarity.SimScorer

Constructor Summary

Constructors

Constructor	Description
ScriptedSimilarity(String weightScriptString, SimilarityWeightScript.Factory weightScriptFactory, String scriptString, SimilarityScript.Factory scriptFactory, boolean discountOverlaps)	Sole constructor.

Method Summary

Modifier and Type	Method	Description
long	computeNorm(FieldInvertState state)	Computes the normalization value for a field, given the accumulated state of term processing for this field (see FieldInvertState).
Similarity.SimScorer	scorer(float boost, CollectionStatistics collectionStats, TermStatistics... termStats)	Compute any collection-level weight (e.g.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

ScriptedSimilarity

public ScriptedSimilarity(String weightScriptString,
                          SimilarityWeightScript.Factory weightScriptFactory,
                          String scriptString,
                          SimilarityScript.Factory scriptFactory,
                          boolean discountOverlaps)

Sole constructor.

Method Detail

toString

public String toString()

Overrides:

toString in class Object

computeNorm

public long computeNorm(FieldInvertState state)

Description copied from class: Similarity

Computes the normalization value for a field, given the accumulated state of term processing for this field (see FieldInvertState).

Matches in longer fields are less precise, so implementations of this method usually set smaller values when state.getLength() is large, and larger values when state.getLength() is small.

Note that for a given term-document frequency, greater unsigned norms must produce scores that are lower or equal, ie. for two encoded norms n1 and n2 so that Long.compareUnsigned(n1, n2) > 0 then SimScorer.score(freq, n1) <= SimScorer.score(freq, n2) for any legal freq.

0 is not a legal norm, so 1 is the norm that produces the highest scores.

Specified by:

computeNorm in class Similarity

Parameters:

state - current processing state for this field

Returns:

computed norm value

scorer

public Similarity.SimScorer scorer(float boost,
                                   CollectionStatistics collectionStats,
                                   TermStatistics... termStats)

Description copied from class: Similarity

Compute any collection-level weight (e.g. IDF, average document length, etc) needed for scoring a query.

Specified by:

scorer in class Similarity

Parameters:

boost - a multiplicative factor to apply to the produces scores

collectionStats - collection-level statistics, such as the number of tokens in the collection.

termStats - term-level statistics, such as the document frequency of a term across the collection.

Returns:

SimWeight object with the information this Similarity needs to score a query.