Package org.apache.lucene.monitor

Interface TermWeightor

All Superinterfaces:

ToDoubleFunction<Term>

public interface TermWeightor
extends ToDoubleFunction<Term>

Calculates the weight of a Term

Field Summary

Fields

Modifier and Type	Field	Description
static TermWeightor	DEFAULT	A default TermWeightor based on token length

Method Summary

Static Methods

Modifier and Type	Method	Description
static TermWeightor	combine(TermWeightor... weightors)	Combine weightors by multiplication
static TermWeightor	fieldWeightor(double weight, String... fields)	QueryTerms with a field from the selected set will be assigned the given weight
static TermWeightor	fieldWeightor(double weight, Set<String> fields)	QueryTerms with a field from the selected set will be assigned the given weight
static TermWeightor	lengthWeightor(double a, double k)	QueryTerms will be assigned a weight based on their term length
static TermWeightor	termAndFieldWeightor(double weight, Set<Term> terms)	QueryTerms with a term and field value from the selected set will be assigned the given weight
static TermWeightor	termAndFieldWeightor(double weight, Term... terms)	QueryTerms with a term and field value from the selected set will be assigned the given weight
static TermWeightor	termFreqWeightor(Map<String,Integer> frequencies, double n, double k)	QueryTerms will be assigned a weight based on their term frequency
static TermWeightor	termWeightor(double weight, Set<BytesRef> terms)	QueryTerms with a term value from the selected set will be assigned the given weight
static TermWeightor	termWeightor(double weight, BytesRef... terms)	QueryTerms with a term value from the selected set will be assigned the given weight

Methods inherited from interface java.util.function.ToDoubleFunction

applyAsDouble

Field Detail

DEFAULT

static final TermWeightor DEFAULT

A default TermWeightor based on token length

Method Detail

combine

static TermWeightor combine(TermWeightor... weightors)

Combine weightors by multiplication

fieldWeightor

static TermWeightor fieldWeightor(double weight,
                                  Set<String> fields)

QueryTerms with a field from the selected set will be assigned the given weight

fieldWeightor

static TermWeightor fieldWeightor(double weight,
                                  String... fields)

QueryTerms with a field from the selected set will be assigned the given weight

termWeightor

static TermWeightor termWeightor(double weight,
                                 Set<BytesRef> terms)

QueryTerms with a term value from the selected set will be assigned the given weight

termWeightor

static TermWeightor termWeightor(double weight,
                                 BytesRef... terms)

QueryTerms with a term value from the selected set will be assigned the given weight

termAndFieldWeightor

static TermWeightor termAndFieldWeightor(double weight,
                                         Set<Term> terms)

QueryTerms with a term and field value from the selected set will be assigned the given weight

termAndFieldWeightor

static TermWeightor termAndFieldWeightor(double weight,
                                         Term... terms)

QueryTerms with a term and field value from the selected set will be assigned the given weight

termFreqWeightor

static TermWeightor termFreqWeightor(Map<String,Integer> frequencies,
                                     double n,
                                     double k)

QueryTerms will be assigned a weight based on their term frequency

More infrequent terms are weighted higher. Terms are weighted according to the function w = (n / freq) + k. Terms with no associated frequency receive a weight of value 1

Parameters:

frequencies - a map of terms to frequencies

n - a scaling factor

k - the minimum weight to scale to

lengthWeightor

static TermWeightor lengthWeightor(double a,
                                   double k)

QueryTerms will be assigned a weight based on their term length

Weights are assigned by the function a * e ^ (-k * length). Longer terms are weighted higher. Terms of length greater than 32 all receive the same weight.

Parameters:

a - a

k - k