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
`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