java.lang.Object
- org.apache.lucene.search.DocIdSet
- - org.apache.lucene.util.FixedBitSet

All Implemented Interfaces:

Bits
```
public final class FixedBitSet
extends DocIdSet
implements Bits
```
BitSet of fixed length (numBits), backed by accessible (getBits()) long[], accessed with an int index, implementing Bits and DocIdSet. Unlike OpenBitSet this bit set does not auto-expand, cannot handle long index, and does not have fastXX/XX variants (just X).

NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.

Nested Class Summary
- Nested classes/interfaces inherited from interface org.apache.lucene.util.Bits
  Bits.MatchAllBits, Bits.MatchNoBits

Field Summary
- Fields inherited from class org.apache.lucene.search.DocIdSet
  EMPTY_DOCIDSET
- Fields inherited from interface org.apache.lucene.util.Bits
  EMPTY_ARRAY

Constructor Summary

Constructors
Constructor Description

FixedBitSet(int numBits)

FixedBitSet(FixedBitSet other)
Makes full copy.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`and(DocIdSetIterator iter)`	Does in-place AND of the bits provided by the iterator.
`void`	`and(FixedBitSet other)`	this = this AND other
`void`	`andNot(DocIdSetIterator iter)`	Does in-place AND NOT of the bits provided by the iterator.
`void`	`andNot(FixedBitSet other)`	this = this AND NOT other
`static int`	`bits2words(int numBits)`	returns the number of 64 bit words it would take to hold numBits
`int`	`cardinality()`	Returns number of set bits.
`void`	`clear(int index)`
`void`	`clear(int startIndex, int endIndex)`	Clears a range of bits.
`Object`	`clone()`
`boolean`	`equals(Object o)`	returns true if both sets have the same bits set
`void`	`flip(int startIndex, int endIndex)`	Flips a range of bits
`boolean`	`get(int index)`
`boolean`	`getAndClear(int index)`
`boolean`	`getAndSet(int index)`
`long[]`	`getBits()`	Expert.
`int`	`hashCode()`
`boolean`	`isCacheable()`	This DocIdSet implementation is cacheable.
`DocIdSetIterator`	`iterator()`	Provides a `DocIdSetIterator` to access the set.
`int`	`length()`
`int`	`nextSetBit(int index)`	Returns the index of the first set bit starting at the index specified.
`void`	`or(DocIdSetIterator iter)`	Does in-place OR of the bits provided by the iterator.
`void`	`or(FixedBitSet other)`	this = this OR other
`int`	`prevSetBit(int index)`	Returns the index of the last set bit before or on the index specified.
`void`	`set(int index)`
`void`	`set(int startIndex, int endIndex)`	Sets a range of bits

Methods inherited from class java.lang.Object
finalize, getClass, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - FixedBitSet
```
public FixedBitSet(int numBits)
```
  - FixedBitSet
```
public FixedBitSet(FixedBitSet other)
```
    Makes full copy.
- Method Detail
  - bits2words
```
public static int bits2words(int numBits)
```
    returns the number of 64 bit words it would take to hold numBits
  - iterator
```
public DocIdSetIterator iterator()
```
    Description copied from class: DocIdSet
    
    Provides a DocIdSetIterator to access the set. This implementation can return null or DocIdSet.EMPTY_DOCIDSET.iterator() if there are no docs that match.
    
    Specified by:
    
    iterator in class DocIdSet
  - length
```
public int length()
```
    Specified by:
    
    length in interface Bits
  - isCacheable
```
public boolean isCacheable()
```
    This DocIdSet implementation is cacheable.
    
    Overrides:
    
    isCacheable in class DocIdSet
  - getBits
```
public long[] getBits()
```
    Expert.
  - cardinality
```
public int cardinality()
```
    Returns number of set bits. NOTE: this visits every long in the backing bits array, and the result is not internally cached!
  - get
```
public boolean get(int index)
```
    Specified by:
    
    get in interface Bits
  - set
```
public void set(int index)
```
  - getAndSet
```
public boolean getAndSet(int index)
```
  - clear
```
public void clear(int index)
```
  - getAndClear
```
public boolean getAndClear(int index)
```
  - nextSetBit
```
public int nextSetBit(int index)
```
    Returns the index of the first set bit starting at the index specified. -1 is returned if there are no more set bits.
  - prevSetBit
```
public int prevSetBit(int index)
```
    Returns the index of the last set bit before or on the index specified. -1 is returned if there are no more set bits.
  - or
```
public void or(DocIdSetIterator iter)
        throws IOException
```
    Does in-place OR of the bits provided by the iterator.
    
    Throws:
    
    IOException
  - or
```
public void or(FixedBitSet other)
```
    this = this OR other
  - and
```
public void and(DocIdSetIterator iter)
         throws IOException
```
    Does in-place AND of the bits provided by the iterator.
    
    Throws:
    
    IOException
  - and
```
public void and(FixedBitSet other)
```
    this = this AND other
  - andNot
```
public void andNot(DocIdSetIterator iter)
            throws IOException
```
    Does in-place AND NOT of the bits provided by the iterator.
    
    Throws:
    
    IOException
  - andNot
```
public void andNot(FixedBitSet other)
```
    this = this AND NOT other
  - flip
```
public void flip(int startIndex,
                 int endIndex)
```
    Flips a range of bits
    
    Parameters:
    
    startIndex - lower index
    
    endIndex - one-past the last bit to flip
  - set
```
public void set(int startIndex,
                int endIndex)
```
    Sets a range of bits
    
    Parameters:
    
    startIndex - lower index
    
    endIndex - one-past the last bit to set
  - clear
```
public void clear(int startIndex,
                  int endIndex)
```
    Clears a range of bits.
    
    Parameters:
    
    startIndex - lower index
    
    endIndex - one-past the last bit to clear
  - clone
```
public Object clone()
```
    Overrides:
    
    clone in class Object
  - equals
```
public boolean equals(Object o)
```
    returns true if both sets have the same bits set
    
    Overrides:
    
    equals in class Object
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class Object

Constructor	Description
`FixedBitSet(int numBits)`
`FixedBitSet(FixedBitSet other)`	Makes full copy.

Class FixedBitSet

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.lucene.util.Bits

Field Summary

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

Fields inherited from interface org.apache.lucene.util.Bits

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

FixedBitSet

FixedBitSet

Method Detail

bits2words

iterator

length

isCacheable

getBits

cardinality

get

set

getAndSet

clear

getAndClear

nextSetBit

prevSetBit

or

or

and

and

andNot

andNot

flip

set

clear

clone

equals

hashCode