org.apache.lucene.codecs.bloom

## Class BloomFilterFactory

- java.lang.Object
- - org.apache.lucene.codecs.bloom.BloomFilterFactory

- Direct Known Subclasses:
    DefaultBloomFilterFactory

      public abstract class BloomFilterFactory
      extends Object

  Class used to create index-time `FuzzySet` appropriately configured for each field. Also called to right-size bitsets for serialization.
  WARNING: This API is experimental and might change in incompatible ways in the next release.

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `BloomFilterFactory()`

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `FuzzySet` | `downsize(FieldInfo fieldInfo, FuzzySet initialSet)` Called when downsizing bitsets for serialization
    `abstract FuzzySet` | `getSetForField(SegmentWriteState state, FieldInfo info)`
    `abstract 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 java.lang.Object

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

- - ### Constructor Detail

    - #### BloomFilterFactory

          public BloomFilterFactory()

  - ### Method Detail

    - #### getSetForField

          public abstract FuzzySet getSetForField(SegmentWriteState state,
                                FieldInfo info)

      Parameters:
        `state` - The content to be indexed
        `info` - the field requiring a BloomFilter
      Returns:
        An appropriately sized set or null if no BloomFiltering required

    - #### downsize

          public FuzzySet downsize(FieldInfo fieldInfo,
                          FuzzySet initialSet)

      Called when downsizing bitsets for serialization
      Parameters:
        `fieldInfo` - The field with sparse set bits
        `initialSet` - The bits accumulated
      Returns:
        null or a hopefully more densely packed, smaller bitset

    - #### isSaturated

          public abstract boolean isSaturated(FuzzySet bloomFilter,
                            FieldInfo fieldInfo)

      Used to determine if the given filter has reached saturation and should be retired i.e. not saved any more
      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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