java.lang.Object
- org.apache.lucene.util.BitSet
- - org.apache.lucene.util.SparseFixedBitSet

All Implemented Interfaces:

Accountable, Bits
```
public class SparseFixedBitSet
extends BitSet
implements Bits, Accountable
```
A bit set that only stores longs that have at least one bit which is set. The way it works is that the space of bits is divided into blocks of 4096 bits, which is 64 longs. Then for each block, we have:
- a long[] which stores the non-zero longs for that block
- a long so that bit i being set means that the i-th long of the block is non-null, and its offset in the array of longs is the number of one bits on the right of the i-th bit.

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

Field Summary

Fields
Modifier and Type	Field	Description
`private static long`	`BASE_RAM_BYTES_USED`
`(package private) long[][]`	`bits`
`(package private) long[]`	`indices`
`(package private) int`	`length`
`private static int`	`MASK_4096`
`(package private) int`	`nonZeroLongCount`
`(package private) long`	`ramBytesUsed`
`private static long`	`SINGLE_ELEMENT_ARRAY_BYTES_USED`

Fields inherited from interface org.apache.lucene.util.Accountable
NULL_ACCOUNTABLE

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

Constructor Summary

Constructors
Constructor Description

SparseFixedBitSet(int length)
Create a SparseFixedBitSet that can contain bits between 0 included and length excluded.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`private void`	`and(int i4096, int i64, long mask)`
`int`	`approximateCardinality()`	Return an approximation of the cardinality of this set.
`private static int`	`blockCount(int length)`
`int`	`cardinality()`	Return the number of bits that are set.
`void`	`clear(int i)`	Clear the bit at index `i`.
`void`	`clear(int from, int to)`	Clears a range of bits.
`private void`	`clearWithinBlock(int i4096, int from, int to)`
`private boolean`	`consistent(int index)`
`private int`	`firstDoc(int i4096)`	Return the first document that occurs on or after the provided block index.
`boolean`	`get(int i)`	Returns the value of the bit with the specified `index`.
`private void`	`insertBlock(int i4096, int i64, int i)`
`private void`	`insertLong(int i4096, int i64, int i, long index)`
`private int`	`lastDoc(int i4096)`	Return the last document that occurs on or before the provided block index.
`int`	`length()`	Returns the number of bits in this set
`private long`	`longBits(long index, long[] bits, int i64)`	Return the long bits at the given `i64` index.
`private static long`	`mask(int from, int to)`
`int`	`nextSetBit(int i)`	Returns the index of the first set bit starting at the index specified.
`private void`	`or(int i4096, long index, long[] bits, int nonZeroLongCount)`
`void`	`or(DocIdSetIterator it)`	Does in-place OR of the bits provided by the iterator.
`private void`	`or(SparseFixedBitSet other)`
`private void`	`orDense(DocIdSetIterator it)`	`or(DocIdSetIterator)` impl that works best when `it` is dense
`private static int`	`oversize(int s)`
`int`	`prevSetBit(int i)`	Returns the index of the last set bit before or on the index specified.
`long`	`ramBytesUsed()`	Return the memory usage of this object in bytes.
`private void`	`removeLong(int i4096, int i64, long index, int o)`
`void`	`set(int i)`	Set the bit at index `i`.
`java.lang.String`	`toString()`

Methods inherited from class org.apache.lucene.util.BitSet
checkUnpositioned, of

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.apache.lucene.util.Accountable
getChildResources

- Field Detail
  - BASE_RAM_BYTES_USED
```
private static final long BASE_RAM_BYTES_USED
```
  - SINGLE_ELEMENT_ARRAY_BYTES_USED
```
private static final long SINGLE_ELEMENT_ARRAY_BYTES_USED
```
  - MASK_4096
```
private static final int MASK_4096
```
    See Also:
    
    Constant Field Values
  - indices
```
final long[] indices
```
  - bits
```
final long[][] bits
```
  - length
```
final int length
```
  - nonZeroLongCount
```
int nonZeroLongCount
```
  - ramBytesUsed
```
long ramBytesUsed
```
- Constructor Detail
  - SparseFixedBitSet
```
public SparseFixedBitSet(int length)
```
    Create a SparseFixedBitSet that can contain bits between 0 included and length excluded.
- Method Detail
  - blockCount
```
private static int blockCount(int length)
```
  - length
```
public int length()
```
    Description copied from interface: Bits
    
    Returns the number of bits in this set
    
    Specified by:
    
    length in interface Bits
  - consistent
```
private boolean consistent(int index)
```
  - cardinality
```
public int cardinality()
```
    Description copied from class: BitSet
    
    Return the number of bits that are set. NOTE: this method is likely to run in linear time
    
    Specified by:
    
    cardinality in class BitSet
  - approximateCardinality
```
public int approximateCardinality()
```
    Description copied from class: BitSet
    
    Return an approximation of the cardinality of this set. Some implementations may trade accuracy for speed if they have the ability to estimate the cardinality of the set without iterating over all the data. The default implementation returns BitSet.cardinality().
    
    Overrides:
    
    approximateCardinality in class BitSet
  - get
```
public boolean get(int i)
```
    Description copied from interface: Bits
    
    Returns the value of the bit with the specified index.
    
    Specified by:
    
    get in interface Bits
    
    Parameters:
    
    i - index, should be non-negative and < Bits.length(). The result of passing negative or out of bounds values is undefined by this interface, just don't do it!
    
    Returns:
    
    true if the bit is set, false otherwise.
  - oversize
```
private static int oversize(int s)
```
  - set
```
public void set(int i)
```
    Set the bit at index i.
    
    Specified by:
    
    set in class BitSet
  - insertBlock
```
private void insertBlock(int i4096,
                         int i64,
                         int i)
```
  - insertLong
```
private void insertLong(int i4096,
                        int i64,
                        int i,
                        long index)
```
  - clear
```
public void clear(int i)
```
    Clear the bit at index i.
    
    Specified by:
    
    clear in class BitSet
  - and
```
private void and(int i4096,
                 int i64,
                 long mask)
```
  - removeLong
```
private void removeLong(int i4096,
                        int i64,
                        long index,
                        int o)
```
  - clear
```
public void clear(int from,
                  int to)
```
    Description copied from class: BitSet
    
    Clears a range of bits.
    
    Specified by:
    
    clear in class BitSet
    
    Parameters:
    
    from - lower index
    
    to - one-past the last bit to clear
  - mask
```
private static long mask(int from,
                         int to)
```
  - clearWithinBlock
```
private void clearWithinBlock(int i4096,
                              int from,
                              int to)
```
  - firstDoc
```
private int firstDoc(int i4096)
```
    Return the first document that occurs on or after the provided block index.
  - nextSetBit
```
public int nextSetBit(int i)
```
    Description copied from class: BitSet
    
    Returns the index of the first set bit starting at the index specified. DocIdSetIterator.NO_MORE_DOCS is returned if there are no more set bits.
    
    Specified by:
    
    nextSetBit in class BitSet
  - lastDoc
```
private int lastDoc(int i4096)
```
    Return the last document that occurs on or before the provided block index.
  - prevSetBit
```
public int prevSetBit(int i)
```
    Description copied from class: BitSet
    
    Returns the index of the last set bit before or on the index specified. -1 is returned if there are no more set bits.
    
    Specified by:
    
    prevSetBit in class BitSet
  - longBits
```
private long longBits(long index,
                      long[] bits,
                      int i64)
```
    Return the long bits at the given i64 index.
  - or
```
private void or(int i4096,
                long index,
                long[] bits,
                int nonZeroLongCount)
```
  - or
```
private void or(SparseFixedBitSet other)
```
  - orDense
```
private void orDense(DocIdSetIterator it)
              throws java.io.IOException
```
    or(DocIdSetIterator) impl that works best when it is dense
    
    Throws:
    
    java.io.IOException
  - or
```
public void or(DocIdSetIterator it)
        throws java.io.IOException
```
    Description copied from class: BitSet
    
    Does in-place OR of the bits provided by the iterator. The state of the iterator after this operation terminates is undefined.
    
    Overrides:
    
    or in class BitSet
    
    Throws:
    
    java.io.IOException
  - ramBytesUsed
```
public long ramBytesUsed()
```
    Description copied from interface: Accountable
    
    Return the memory usage of this object in bytes. Negative values are illegal.
    
    Specified by:
    
    ramBytesUsed in interface Accountable
  - toString
```
public java.lang.String toString()
```
    Overrides:
    
    toString in class java.lang.Object

Class SparseFixedBitSet

Nested Class Summary

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

Field Summary

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

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

Constructor Summary

Method Summary

Methods inherited from class org.apache.lucene.util.BitSet

Methods inherited from class java.lang.Object

Methods inherited from interface org.apache.lucene.util.Accountable

Field Detail

BASE_RAM_BYTES_USED

SINGLE_ELEMENT_ARRAY_BYTES_USED

MASK_4096

indices

bits

length

nonZeroLongCount

ramBytesUsed

Constructor Detail

SparseFixedBitSet

Method Detail

blockCount

length

consistent

cardinality

approximateCardinality

get

oversize

set

insertBlock

insertLong

clear

and

removeLong

clear

mask

clearWithinBlock

firstDoc

nextSetBit

lastDoc

prevSetBit

longBits

or

or

orDense

or

ramBytesUsed

toString