org.apache.lucene.util

Class BitSet

java.lang.Object

org.apache.lucene.util.BitSet

All Implemented Interfaces:

Accountable, Bits, MutableBits

Direct Known Subclasses:

FixedBitSet, SparseFixedBitSet

public abstract class BitSet
extends Object
implements MutableBits, Accountable

Base implementation for a bit set.

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 interface org.apache.lucene.util.Bits

EMPTY_ARRAY

Constructor Summary

Constructors

Constructor and Description
BitSet()

Method Summary

Modifier and Type	Method and Description
int	approximateCardinality() Return an approximation of the cardinality of this set.
protected void	assertUnpositioned(DocIdSetIterator iter) Assert that the current doc is -1.
abstract int	cardinality() Return the number of bits that are set.
abstract void	clear(int startIndex, int endIndex) Clears a range of bits.
abstract int	nextSetBit(int index) Returns the index of the first set bit starting at the index specified.
static BitSet	of(DocIdSetIterator it, int maxDoc) Build a BitSet from the content of the provided DocIdSetIterator.
void	or(DocIdSetIterator iter) Does in-place OR of the bits provided by the iterator.
abstract int	prevSetBit(int index) Returns the index of the last set bit before or on the index specified.
abstract void	set(int i) Set the bit at i.

Methods inherited from class java.lang.Object

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

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

clear

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

get, length

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

getChildResources, ramBytesUsed

Constructor Detail

BitSet

public BitSet()

Method Detail

of

public static BitSet of(DocIdSetIterator it,
                        int maxDoc)
                 throws IOException

Build a BitSet from the content of the provided DocIdSetIterator. NOTE: this will fully consume the DocIdSetIterator.

Throws:

IOException

set

public abstract void set(int i)

Set the bit at i.

clear

public abstract void clear(int startIndex,
                           int endIndex)

Clears a range of bits.

Parameters:

startIndex - lower index

endIndex - one-past the last bit to clear

cardinality

public abstract int cardinality()

Return the number of bits that are set. NOTE: this method is likely to run in linear time

approximateCardinality

public int approximateCardinality()

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 cardinality().

prevSetBit

public abstract 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.

nextSetBit

public abstract int nextSetBit(int index)

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.

assertUnpositioned

protected final void assertUnpositioned(DocIdSetIterator iter)

Assert that the current doc is -1.

or

public void or(DocIdSetIterator iter)
        throws IOException

Does in-place OR of the bits provided by the iterator. The state of the iterator after this operation terminates is undefined.

Throws:

IOException