Package com.intellij.util.containers

Class ConcurrentBitSet

java.lang.Object

com.intellij.util.containers.ConcurrentBitSet

public class ConcurrentBitSet
extends java.lang.Object

This class is a thread-safe version of the java.util.BitSet except for some methods which don't make sense in concurrent environment or those i was too lazy to implement. Implementation: bits stored packed in array, 32 bits per array element. When bit change request comes, the array is reallocated as necessary.

See Also:

BitSet

Constructor Summary

Constructors

Constructor and Description
ConcurrentBitSet()

Method Summary

Modifier and Type	Method and Description
void	clear() Clear method in presense of concurrency complicates everything to no end.
boolean	clear(int bitIndex) Sets the bit specified by the index to false.
boolean	flip(int bitIndex) Sets the bit at the specified index to the complement of its current value.
boolean	get(int bitIndex) Returns the value of the bit with the specified index.
int	nextClearBit(int fromIndex) Returns the index of the first bit that is set to false that occurs on or after the specified starting index.
int	nextSetBit(int fromIndex) Returns the index of the first bit that is set to true that occurs on or after the specified starting index.
static ConcurrentBitSet	readFrom(java.io.File file)
boolean	set(int bitIndex) Sets the bit at the specified index to true.
void	set(int bitIndex, boolean value) Sets the bit at the specified index to the specified value.
int	size() Returns the number of bits of space actually in use
int []	toIntArray()
java.lang.String	toString() Returns a string representation of this bit set.
void	writeTo(java.io.File file)

Methods inherited from class java.lang.Object

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

Constructor Detail

ConcurrentBitSet

public ConcurrentBitSet()

Method Detail

flip

public boolean flip(int bitIndex)

Sets the bit at the specified index to the complement of its current value.

Parameters:

bitIndex - the index of the bit to flip

Returns:

new bit value

Throws:

java.lang.IndexOutOfBoundsException - if the specified index is negative

set

public boolean set(int bitIndex)

Sets the bit at the specified index to true.

Parameters:

bitIndex - a bit index

Returns:

previous value

Throws:

java.lang.IndexOutOfBoundsException - if the specified index is negative

set

public void set(int bitIndex,
                boolean value)

Sets the bit at the specified index to the specified value.

Parameters:

bitIndex - a bit index

value - a boolean value to set

Throws:

java.lang.IndexOutOfBoundsException - if the specified index is negative

clear

public boolean clear(int bitIndex)

Sets the bit specified by the index to false.

Parameters:

bitIndex - the index of the bit to be cleared

Returns:

previous value

Throws:

java.lang.IndexOutOfBoundsException - if the specified index is negative

clear

public void clear()

Clear method in presense of concurrency complicates everything to no end. PLEASE REWRITE EVERY OTHER METHOD IF EVER DECIDE TO IMPLEMENT THIS

get

public boolean get(int bitIndex)

Returns the value of the bit with the specified index. The value is true if the bit with the index bitIndex is currently set; otherwise, the result is false.

Parameters:

bitIndex - the bit index

Returns:

the value of the bit with the specified index

Throws:

java.lang.IndexOutOfBoundsException - if the specified index is negative

nextSetBit

public int nextSetBit(int fromIndex)

Returns the index of the first bit that is set to true that occurs on or after the specified starting index. If no such bit exists then -1 is returned.

To iterate over the true bits, use the following loop:

 
 for (int i = bs.nextSetBit(0); i >= 0; i = bs.nextSetBit(i+1)) {
     // operate on index i here
 }

Parameters:

fromIndex - the index to start checking from (inclusive)

Returns:

the index of the next set bit, or -1 if there is no such bit

Throws:

java.lang.IndexOutOfBoundsException - if the specified index is negative

nextClearBit

public int nextClearBit(int fromIndex)

Returns the index of the first bit that is set to false that occurs on or after the specified starting index.

Parameters:

fromIndex - the index to start checking from (inclusive)

Returns:

the index of the next clear bit

Throws:

java.lang.IndexOutOfBoundsException - if the specified index is negative

size

public int size()

Returns the number of bits of space actually in use

Returns:

the number of bits currently in this bit set

toString

public java.lang.String toString()

Returns a string representation of this bit set. For every index which contains a bit in the set state, the decimal representation of that index is included in the result. Such indices are listed in order from lowest to highest, separated by ", " (a comma and a space) and surrounded by braces, resulting in the usual mathematical notation for a set of integers.

Overrides:

toString in class java.lang.Object

Returns:

a string representation of this bit set

toIntArray

public int [] toIntArray()

writeTo

public void writeTo(java.io.File file)
             throws java.io.IOException

Throws:

java.io.IOException

readFrom

public static ConcurrentBitSet readFrom(java.io.File file)
                                 throws java.io.IOException

Throws:

java.io.IOException