com.bericotech.clavin.index
Class BinarySimilarity

java.lang.Object
  org.apache.lucene.search.similarities.Similarity
      org.apache.lucene.search.similarities.TFIDFSimilarity
          org.apache.lucene.search.similarities.DefaultSimilarity
              com.bericotech.clavin.index.BinarySimilarity

public class BinarySimilarity
extends org.apache.lucene.search.similarities.DefaultSimilarity

Turns TF (term frequency) into a binary (yes/no) proposition in calculating Lucene relevance score.

Nested Class Summary

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

org.apache.lucene.search.similarities.Similarity.ExactSimScorer, org.apache.lucene.search.similarities.Similarity.SimWeight, org.apache.lucene.search.similarities.Similarity.SloppySimScorer

Field Summary

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

discountOverlaps

Constructor Summary

BinarySimilarity()
Simple default constructor for BinarySimilarity.

Method Summary

float

tf(float freq) Ignores multiple appearance of the query term in the index document field, effectively making TF (term frequency) a yes/no proposition (i.e., zero is still zero, but you don't get extra points for a query term being found multiple times in an index document field).

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

computeNorm, coord, getDiscountOverlaps, idf, queryNorm, scorePayload, setDiscountOverlaps, sloppyFreq, toString

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

computeWeight, decodeNormValue, encodeNormValue, exactSimScorer, idfExplain, idfExplain, sloppySimScorer, tf

Methods inherited from class java.lang.Object

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

Constructor Detail

BinarySimilarity

public BinarySimilarity()

Simple default constructor for BinarySimilarity.

Method Detail

tf

public float tf(float freq)

Ignores multiple appearance of the query term in the index document field, effectively making TF (term frequency) a yes/no proposition (i.e., zero is still zero, but you don't get extra points for a query term being found multiple times in an index document field).

Overrides:

tf in class org.apache.lucene.search.similarities.DefaultSimilarity

Parameters:

freq - floating-point number being converted to 1.0 or 0.0