org.apache.lucene.codecs.bloom
Class DefaultBloomFilterFactory

java.lang.Object
  extended by org.apache.lucene.codecs.bloom.BloomFilterFactory
      extended by org.apache.lucene.codecs.bloom.DefaultBloomFilterFactory

public class DefaultBloomFilterFactory
extends BloomFilterFactory

Default policy is to allocate a bitset with 10% saturation given a unique term per document. Bits are set via MurmurHash2 hashing function.

WARNING: This API is experimental and might change in incompatible ways in the next release.

Constructor Summary
DefaultBloomFilterFactory()
           
 
Method Summary
 FuzzySet getSetForField(SegmentWriteState state, FieldInfo info)
           
 boolean isSaturated(FuzzySet bloomFilter, FieldInfo fieldInfo)
          Used to determine if the given filter has reached saturation and should be retired i.e.
 
Methods inherited from class org.apache.lucene.codecs.bloom.BloomFilterFactory
downsize
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

DefaultBloomFilterFactory

public DefaultBloomFilterFactory()
Method Detail

getSetForField

public FuzzySet getSetForField(SegmentWriteState state,
                               FieldInfo info)
Specified by:
getSetForField in class BloomFilterFactory
Parameters:
state - The content to be indexed
info - the field requiring a BloomFilter
Returns:
An appropriately sized set or null if no BloomFiltering required

isSaturated

public boolean isSaturated(FuzzySet bloomFilter,
                           FieldInfo fieldInfo)
Description copied from class: BloomFilterFactory
Used to determine if the given filter has reached saturation and should be retired i.e. not saved any more

Specified by:
isSaturated in class BloomFilterFactory
Parameters:
bloomFilter - The bloomFilter being tested
fieldInfo - The field with which this filter is associated
Returns:
true if the set has reached saturation and should be retired


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