org.opencms.search
Class CmsSearchSimilarity

java.lang.Object
  org.apache.lucene.search.Similarity
      org.apache.lucene.search.DefaultSimilarity
          org.opencms.search.CmsSearchSimilarity

All Implemented Interfaces:

Serializable

public class CmsSearchSimilarity
extends org.apache.lucene.search.DefaultSimilarity

Reduces the importance of the computeNorm(String, FieldInvertState) factor for the CmsSearchField.FIELD_CONTENT field, while keeping the Lucene default for all other fields.

This implementation was added since apparently the default length norm is heavily biased for small documents. In the default, even if a term is found in 2 documents the same number of times, the smaller document (containing less terms) will have a score easily 3x as high as the longer document. Using this implementation the importance of the term number is reduced.

Inspired by Chuck Williams WikipediaSimilarity.

Since:

6.0.0

See Also:

Serialized Form

Field Summary

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

discountOverlaps

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

NO_DOC_ID_PROVIDED

Constructor Summary

CmsSearchSimilarity()
Creates a new instance of the OpenCms search similarity.

Method Summary

float

computeNorm(String fieldName, org.apache.lucene.index.FieldInvertState state) Special implementation for "compute norm" to reduce the significance of this factor for the CmsSearchField.FIELD_CONTENT field, while keeping the Lucene default for all other fields.

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

coord, getDiscountOverlaps, idf, queryNorm, setDiscountOverlaps, sloppyFreq, tf

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

decodeNorm, decodeNormValue, encodeNorm, encodeNormValue, getDefault, getNormDecoder, idfExplain, idfExplain, idfExplain, lengthNorm, scorePayload, setDefault, tf

Methods inherited from class java.lang.Object

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

Constructor Detail

CmsSearchSimilarity

public CmsSearchSimilarity()

Creates a new instance of the OpenCms search similarity.

Method Detail

computeNorm

public float computeNorm(String fieldName,
                         org.apache.lucene.index.FieldInvertState state)

Special implementation for "compute norm" to reduce the significance of this factor for the CmsSearchField.FIELD_CONTENT field, while keeping the Lucene default for all other fields.

Overrides:

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

See Also:

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