org.ow2.weblab.services.duplicates
Class CustomSimilarity

java.lang.Object
  org.apache.lucene.search.Similarity
      org.ow2.weblab.services.duplicates.CustomSimilarity

All Implemented Interfaces:

java.io.Serializable

public class CustomSimilarity
extends org.apache.lucene.search.Similarity

Expert: Default scoring implementation.

See Also:

Serialized Form

Field Summary

protected boolean

discountOverlaps

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

NO_DOC_ID_PROVIDED

Constructor Summary

CustomSimilarity()

Method Summary

float	computeNorm(java.lang.String field, org.apache.lucene.index.FieldInvertState state) Implemented as state.getBoost()*lengthNorm(numTerms), where numTerms is FieldInvertState.getLength() if setDiscountOverlaps(boolean) is false, else it's FieldInvertState.getLength() - FieldInvertState.getNumOverlap().
float	coord(int overlap, int maxOverlap) Implemented as overlap / maxOverlap.
boolean	getDiscountOverlaps()
float	idf(int docFreq, int numDocs) Implemented as log(numDocs/(docFreq+1)) + 1.
float	lengthNorm(java.lang.String fieldName, int numTerms) Implemented as 1/sqrt(numTerms).
float	queryNorm(float sumOfSquaredWeights) Implemented as 1/sqrt(sumOfSquaredWeights).
void	setDiscountOverlaps(boolean v) Determines whether overlap tokens (Tokens with 0 position increment) are ignored when computing norm.
float	sloppyFreq(int distance) Implemented as 1 / (distance + 1).
float	tf(float freq) Implemented as sqrt(freq).

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

decodeNorm, encodeNorm, getDefault, getNormDecoder, idf, idf, idfExplain, idfExplain, scorePayload, scorePayload, setDefault, tf

Methods inherited from class java.lang.Object

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

Field Detail

discountOverlaps

protected boolean discountOverlaps

Constructor Detail

CustomSimilarity

public CustomSimilarity()

Method Detail

computeNorm

public float computeNorm(java.lang.String field,
                         org.apache.lucene.index.FieldInvertState state)

Implemented as state.getBoost()*lengthNorm(numTerms), where numTerms is FieldInvertState.getLength() if setDiscountOverlaps(boolean) is false, else it's FieldInvertState.getLength() - FieldInvertState.getNumOverlap().

WARNING: This API is new and experimental, and may suddenly change.

Overrides:

computeNorm in class org.apache.lucene.search.Similarity

lengthNorm

public float lengthNorm(java.lang.String fieldName,
                        int numTerms)

Implemented as 1/sqrt(numTerms).

Specified by:

lengthNorm in class org.apache.lucene.search.Similarity

queryNorm

public float queryNorm(float sumOfSquaredWeights)

Implemented as 1/sqrt(sumOfSquaredWeights).

Specified by:

queryNorm in class org.apache.lucene.search.Similarity

tf

public float tf(float freq)

Implemented as sqrt(freq).

Specified by:

tf in class org.apache.lucene.search.Similarity

sloppyFreq

public float sloppyFreq(int distance)

Implemented as 1 / (distance + 1).

Specified by:

sloppyFreq in class org.apache.lucene.search.Similarity

idf

public float idf(int docFreq,
                 int numDocs)

Implemented as log(numDocs/(docFreq+1)) + 1.

Specified by:

idf in class org.apache.lucene.search.Similarity

coord

public float coord(int overlap,
                   int maxOverlap)

Implemented as overlap / maxOverlap.

Specified by:

coord in class org.apache.lucene.search.Similarity

setDiscountOverlaps

public void setDiscountOverlaps(boolean v)

Determines whether overlap tokens (Tokens with 0 position increment) are ignored when computing norm. By default this is false, meaning overlap tokens are counted just like non-overlap tokens.

WARNING: This API is new and experimental, and may suddenly change.

See Also:

computeNorm(java.lang.String, org.apache.lucene.index.FieldInvertState)

getDiscountOverlaps

public boolean getDiscountOverlaps()

See Also:

setDiscountOverlaps(boolean)