com.jalios.jcms.search

Class CustomSimilarity

java.lang.Object

org.apache.lucene.search.similarities.Similarity

org.apache.lucene.search.similarities.TFIDFSimilarity

org.apache.lucene.search.similarities.ClassicSimilarity

com.jalios.jcms.search.CustomSimilarity

public class CustomSimilarity
extends org.apache.lucene.search.similarities.ClassicSimilarity

Custom scoring implementation.

Nested Class Summary

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

org.apache.lucene.search.similarities.Similarity.SimScorer, org.apache.lucene.search.similarities.Similarity.SimWeight

Field Summary

Fields inherited from class org.apache.lucene.search.similarities.ClassicSimilarity

discountOverlaps

Constructor Summary

Constructors

Constructor and Description
CustomSimilarity()

Method Summary

Modifier and Type	Method and Description
float	coord(int overlap, int maxOverlap) In JCMS, document fields are used for title/abstract/allfield, but contrary to the default behavior of Lucene similarity, if a match occured in several of those field as compared to only one, it should not change the score.
float	lengthNorm(org.apache.lucene.index.FieldInvertState state) We do not want long text to be less important than short text.

Methods inherited from class org.apache.lucene.search.similarities.ClassicSimilarity

decodeNormValue, encodeNormValue, getDiscountOverlaps, idf, idfExplain, queryNorm, scorePayload, setDiscountOverlaps, sloppyFreq, tf, toString

Methods inherited from class org.apache.lucene.search.similarities.TFIDFSimilarity

computeNorm, computeWeight, idfExplain, simScorer

Methods inherited from class java.lang.Object

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

Constructor Detail

CustomSimilarity

public CustomSimilarity()

Method Detail

lengthNorm

public float lengthNorm(org.apache.lucene.index.FieldInvertState state)

We do not want long text to be less important than short text. Therefore always return 1 for this normalization value to have no impact. This value is computed during indexing and stored in the index.

Overrides:

lengthNorm in class org.apache.lucene.search.similarities.ClassicSimilarity

coord

public float coord(int overlap,
                   int maxOverlap)

In JCMS, document fields are used for title/abstract/allfield, but contrary to the default behavior of Lucene similarity, if a match occured in several of those field as compared to only one, it should not change the score.

Indeed, the field boost already takes care of the higher relevance of title vs abstract vs other.

Overrides:

coord in class org.apache.lucene.search.similarities.ClassicSimilarity