BitVector (Lucene 2.9.4 API)

java.lang.Object
- org.apache.lucene.util.BitVector

All Implemented Interfaces:

java.lang.Cloneable
```
public final class BitVector
extends java.lang.Object
implements java.lang.Cloneable
```
Optimized implementation of a vector of bits. This is more-or-less like java.util.BitSet, but also includes the following:
- a count() method, which efficiently computes the number of one bits;
- optimized read from and write to disk;
- inlinable get() method;
- store and load, as bit set or d-gaps, depending on sparseness;
Version:

$Id: BitVector.java 950306 2010-06-01 23:33:34Z mikemccand $

Constructor Summary

Constructors
Constructor and Description
`BitVector(Directory d, java.lang.String name)` Constructs a bit vector from the file `name` in Directory `d`, as written by the `write(org.apache.lucene.store.Directory, java.lang.String)` method.
`BitVector(int n)` Constructs a vector capable of holding `n` bits.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`clear(int bit)` Sets the value of `bit` to zero.
`java.lang.Object`	`clone()`
`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.
`boolean`	`getAndSet(int bit)` Sets the value of `bit` to true, and returns true if bit was already set
`int`	`getRecomputedCount()` For testing
`void`	`set(int bit)` Sets the value of `bit` to one.
`int`	`size()` Returns the number of bits in this vector.
`BitVector`	`subset(int start, int end)` Retrieve a subset of this BitVector.
`void`	`write(Directory d, java.lang.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)`.

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

- Constructor Detail
  - BitVector
```
public BitVector(int n)
```
    Constructs a vector capable of holding n bits.
  - BitVector
```
public BitVector(Directory d,
                 java.lang.String name)
          throws java.io.IOException
```
    Constructs a bit vector from the file name in Directory d, as written by the write(org.apache.lucene.store.Directory, java.lang.String) method.
    
    Throws:
    
    java.io.IOException
- Method Detail
  - clone
```
public java.lang.Object clone()
```
    Overrides:
    
    clone in class java.lang.Object
  - set
```
public final void set(int bit)
```
    Sets the value of bit to one.
  - getAndSet
```
public final boolean getAndSet(int bit)
```
    Sets the value of bit to true, and returns true if bit was already set
  - clear
```
public final void clear(int bit)
```
    Sets the value of bit to zero.
  - get
```
public final boolean get(int bit)
```
    Returns true if bit is one and false if it is zero.
  - 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.
  - 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.
  - getRecomputedCount
```
public final int getRecomputedCount()
```
    For testing
  - write
```
public final void write(Directory d,
                        java.lang.String name)
                 throws java.io.IOException
```
    Writes this vector to the file name in Directory d, in a format that can be read by the constructor BitVector(Directory, String).
    
    Throws:
    
    java.io.IOException
  - subset
```
public BitVector subset(int start,
                        int end)
```
    Retrieve a subset of this BitVector.
    
    Parameters:
    
    start - starting index, inclusive
    
    end - ending index, exclusive
    
    Returns:
    
    subset

Class BitVector

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

BitVector

BitVector

Method Detail

clone

set

getAndSet

clear

get

size

count

getRecomputedCount

write

subset