org.apache.lucene.util

Class BitVector


public final class BitVector
extends Object

Optimized implementation of a vector of bits. This is more-or-less like java.util.BitSet, but also includes the following:
Version:
$Id: BitVector.java 494136 2007-01-08 18:11:08Z mikemccand $
Author:
Doug Cutting

Constructor Summary

BitVector(int n)
Constructs a vector capable of holding n bits.
BitVector(Directory d, String name)
Constructs a bit vector from the file name in Directory d, as written by the write(Directory,String) method.

Method Summary

void
clear(int bit)
Sets the value of bit to zero.
int
count()
Returns the total number of one bits in this vector.
boolean
get(int bit)
Returns true if bit is one and false if it is zero.
void
set(int bit)
Sets the value of bit to one.
int
size()
Returns the number of bits in this vector.
void
write(Directory d, String name)
Writes this vector to the file name in Directory d, in a format that can be read by the constructor BitVector(Directory,String).

Constructor Details

BitVector

public BitVector(int n)
Constructs a vector capable of holding n bits.

BitVector

public BitVector(Directory d,
                 String name)
            throws IOException
Constructs a bit vector from the file name in Directory d, as written by the write(Directory,String) method.

Method Details

clear

public final void clear(int bit)
Sets the value of bit to zero.

count

public final int count()
Returns the total number of one bits in this vector. This is efficiently computed and cached, so that, if the vector is not changed, no recomputation is done for repeated calls.

get

public final boolean get(int bit)
Returns true if bit is one and false if it is zero.

set

public final void set(int bit)
Sets the value of bit to one.

size

public final int size()
Returns the number of bits in this vector. This is also one greater than the number of the largest valid bit number.

write

public final void write(Directory d,
                        String name)
            throws IOException
Writes this vector to the file name in Directory d, in a format that can be read by the constructor BitVector(Directory,String).

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