Added in API level 1

BitSet

open class BitSet : Cloneable, Serializable

kotlin.Any
↳	java.util.BitSet

This class implements a vector of bits that grows as needed. Each component of the bit set has a boolean value. The bits of a BitSet are indexed by nonnegative integers. Individual indexed bits can be examined, set, or cleared. One BitSet may be used to modify the contents of another BitSet through logical AND, logical inclusive OR, and logical exclusive OR operations.

By default, all bits in the set initially have the value false.

Every bit set has a current size, which is the number of bits of space currently in use by the bit set. Note that the size is related to the implementation of a bit set, so it may change with implementation. The length of a bit set relates to logical length of a bit set and is defined independently of implementation.

Unless otherwise noted, passing a null parameter to any of the methods in a BitSet will result in a NullPointerException.

A BitSet is not safe for multithreaded use without external synchronization.

Summary

Public constructors
BitSet() Creates a new bit set.
BitSet(nbits: Int) Creates a bit set whose initial size is large enough to explicitly represent bits with indices in the range 0 through nbits-1.

Public methods
open Unit	and(set: BitSet!) Performs a logical AND of this target bit set with the argument bit set.
open Unit	andNot(set: BitSet!) Clears all of the bits in this BitSet whose corresponding bit is set in the specified BitSet.
open Int	cardinality() Returns the number of bits set to true in this BitSet.
open Unit	clear() Sets all of the bits in this BitSet to false.
open Unit	clear(bitIndex: Int) Sets the bit specified by the index to false.
open Unit	clear(fromIndex: Int, toIndex: Int) Sets the bits from the specified fromIndex (inclusive) to the specified toIndex (exclusive) to false.
open Any	clone() Cloning this BitSet produces a new BitSet that is equal to it.
open Boolean	equals(other: Any?) Compares this object against the specified object.
open Unit	flip(bitIndex: Int) Sets the bit at the specified index to the complement of its current value.
open Unit	flip(fromIndex: Int, toIndex: Int) Sets each bit from the specified fromIndex (inclusive) to the specified toIndex (exclusive) to the complement of its current value.
open Boolean	get(bitIndex: Int) Returns the value of the bit with the specified index.
open BitSet!	get(fromIndex: Int, toIndex: Int) Returns a new BitSet composed of bits from this BitSet from fromIndex (inclusive) to toIndex (exclusive).
open Int	hashCode() Returns the hash code value for this bit set.
open Boolean	intersects(set: BitSet!) Returns true if the specified BitSet has any bits set to true that are also set to true in this BitSet.
open Boolean	isEmpty() Returns true if this BitSet contains no bits that are set to true.
open Int	length() Returns the "logical size" of this BitSet: the index of the highest set bit in the BitSet plus one.
open Int	nextClearBit(fromIndex: Int) Returns the index of the first bit that is set to false that occurs on or after the specified starting index.
open Int	nextSetBit(fromIndex: Int) Returns the index of the first bit that is set to true that occurs on or after the specified starting index.
open Unit	or(set: BitSet!) Performs a logical OR of this bit set with the bit set argument.
open Int	previousClearBit(fromIndex: Int) Returns the index of the nearest bit that is set to false that occurs on or before the specified starting index.
open Int	previousSetBit(fromIndex: Int) Returns the index of the nearest bit that is set to true that occurs on or before the specified starting index.
open Unit	set(bitIndex: Int) Sets the bit at the specified index to true.
open Unit	set(bitIndex: Int, value: Boolean) Sets the bit at the specified index to the specified value.
open Unit	set(fromIndex: Int, toIndex: Int) Sets the bits from the specified fromIndex (inclusive) to the specified toIndex (exclusive) to true.
open Unit	set(fromIndex: Int, toIndex: Int, value: Boolean) Sets the bits from the specified fromIndex (inclusive) to the specified toIndex (exclusive) to the specified value.
open Int	size() Returns the number of bits of space actually in use by this BitSet to represent bit values.
open IntStream!	stream() Returns a stream of indices for which this BitSet contains a bit in the set state.
open ByteArray!	toByteArray() Returns a new byte array containing all the bits in this bit set.
open LongArray!	toLongArray() Returns a new long array containing all the bits in this bit set.
open String	toString() Returns a string representation of this bit set.
open static BitSet!	valueOf(bytes: ByteArray!) Returns a new bit set containing all the bits in the given byte array.
open static BitSet!	valueOf(bb: ByteBuffer!) Returns a new bit set containing all the bits in the given byte buffer between its position and limit.
open static BitSet!	valueOf(lb: LongBuffer!) Returns a new bit set containing all the bits in the given long buffer between its position and limit.
open static BitSet!	valueOf(longs: LongArray!) Returns a new bit set containing all the bits in the given long array.
open Unit	xor(set: BitSet!) Performs a logical XOR of this bit set with the bit set argument.

Public constructors

BitSet

Added in API level 1

BitSet()

Creates a new bit set. All bits are initially false.

BitSet

Added in API level 1

BitSet(nbits: Int)

Creates a bit set whose initial size is large enough to explicitly represent bits with indices in the range 0 through nbits-1. All bits are initially false.

Parameters
nbits	Int: the initial size of the bit set

Exceptions
java.lang.NegativeArraySizeException	if the specified initial size is negative

Public methods

and

Added in API level 1

open fun and(set: BitSet!): Unit

Performs a logical AND of this target bit set with the argument bit set. This bit set is modified so that each bit in it has the value true if and only if it both initially had the value true and the corresponding bit in the bit set argument also had the value true.

Parameters
set	BitSet!: a bit set

andNot

Added in API level 1

open fun andNot(set: BitSet!): Unit

Clears all of the bits in this BitSet whose corresponding bit is set in the specified BitSet.

Parameters
set	BitSet!: the BitSet with which to mask this BitSet

cardinality

Added in API level 1

open fun cardinality(): Int

Returns the number of bits set to true in this BitSet.

Return
Int	the number of bits set to true in this BitSet

clear

Added in API level 1

open fun clear(): Unit

Sets all of the bits in this BitSet to false.

clear

Added in API level 1

open fun clear(bitIndex: Int): Unit

Sets the bit specified by the index to false.

Parameters
bitIndex	Int: the index of the bit to be cleared

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

clear

Added in API level 1

open fun clear(
    fromIndex: Int, 
    toIndex: Int
): Unit

Sets the bits from the specified fromIndex (inclusive) to the specified toIndex (exclusive) to false.

Parameters
fromIndex	Int: index of the first bit to be cleared
toIndex	Int: index after the last bit to be cleared

Exceptions
java.lang.IndexOutOfBoundsException	if fromIndex is negative, or toIndex is negative, or fromIndex is larger than toIndex

clone

Added in API level 1

open fun clone(): Any

Cloning this BitSet produces a new BitSet that is equal to it. The clone of the bit set is another bit set that has exactly the same bits set to true as this bit set.

Return
Any	a clone of this bit set

Exceptions
java.lang.CloneNotSupportedException	if the object's class does not support the Cloneable interface. Subclasses that override the clone method can also throw this exception to indicate that an instance cannot be cloned.

See Also

• #size()

equals

Added in API level 1

open fun equals(other: Any?): Boolean

Compares this object against the specified object. The result is true if and only if the argument is not null and is a BitSet object that has exactly the same set of bits set to true as this bit set. That is, for every nonnegative int index k,

((BitSet)obj).get(k) == this.get(k)

must be true. The current sizes of the two bit sets are not compared.

Parameters
obj	the object to compare with

Return
Boolean	true if the objects are the same; false otherwise

See Also

• #size()

flip

Added in API level 1

open fun flip(bitIndex: Int): Unit

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

Parameters
bitIndex	Int: the index of the bit to flip

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

flip

Added in API level 1

open fun flip(
    fromIndex: Int, 
    toIndex: Int
): Unit

Sets each bit from the specified fromIndex (inclusive) to the specified toIndex (exclusive) to the complement of its current value.

Parameters
fromIndex	Int: index of the first bit to flip
toIndex	Int: index after the last bit to flip

Exceptions
java.lang.IndexOutOfBoundsException	if fromIndex is negative, or toIndex is negative, or fromIndex is larger than toIndex

get

Added in API level 1

open fun get(bitIndex: Int): Boolean

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

Parameters
bitIndex	Int: the bit index

Return
Boolean	the value of the bit with the specified index

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

get

Added in API level 1

open fun get(
    fromIndex: Int, 
    toIndex: Int
): BitSet!

Returns a new BitSet composed of bits from this BitSet from fromIndex (inclusive) to toIndex (exclusive).

Parameters
fromIndex	Int: index of the first bit to include
toIndex	Int: index after the last bit to include

Return
BitSet!	a new BitSet from a range of this BitSet

Exceptions
java.lang.IndexOutOfBoundsException	if fromIndex is negative, or toIndex is negative, or fromIndex is larger than toIndex

hashCode

Added in API level 1

open fun hashCode(): Int

Returns the hash code value for this bit set. The hash code depends only on which bits are set within this BitSet.

The hash code is defined to be the result of the following calculation:

<code>public int hashCode() {
      long h = 1234;
      long[] words = toLongArray();
      for (int i = words.length; --i &gt;= 0; )
          h ^= words[i] * (i + 1);
      return (int)((h &gt;&gt; 32) ^ h);
  }</code>

Note that the hash code changes if the set of bits is altered.

Return
Int	the hash code value for this bit set

intersects

Added in API level 1

open fun intersects(set: BitSet!): Boolean

Returns true if the specified BitSet has any bits set to true that are also set to true in this BitSet.

Parameters
set	BitSet!: BitSet to intersect with

Return
Boolean	boolean indicating whether this BitSet intersects the specified BitSet

isEmpty

Added in API level 1

open fun isEmpty(): Boolean

Returns true if this BitSet contains no bits that are set to true.

Return
Boolean	boolean indicating whether this BitSet is empty

length

Added in API level 1

open fun length(): Int

Returns the "logical size" of this BitSet: the index of the highest set bit in the BitSet plus one. Returns zero if the BitSet contains no set bits.

Return
Int	the logical size of this BitSet

nextClearBit

Added in API level 1

open fun nextClearBit(fromIndex: Int): Int

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

Parameters
fromIndex	Int: the index to start checking from (inclusive)

Return
Int	the index of the next clear bit

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

nextSetBit

Added in API level 1

open fun nextSetBit(fromIndex: Int): Int

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 in a BitSet, use the following loop:

<code>for (int i = bs.nextSetBit(0); i &gt;= 0; i = bs.nextSetBit(i+1)) {
      // operate on index i here
      if (i == Integer.MAX_VALUE) {
          break; // or (i+1) would overflow
      }
  }</code>

Parameters
fromIndex	Int: the index to start checking from (inclusive)

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

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

or

Added in API level 1

open fun or(set: BitSet!): Unit

Performs a logical OR of this bit set with the bit set argument. This bit set is modified so that a bit in it has the value true if and only if it either already had the value true or the corresponding bit in the bit set argument has the value true.

Parameters
set	BitSet!: a bit set

previousClearBit

Added in API level 19

open fun previousClearBit(fromIndex: Int): Int

Returns the index of the nearest bit that is set to false that occurs on or before the specified starting index. If no such bit exists, or if -1 is given as the starting index, then -1 is returned.

Parameters
fromIndex	Int: the index to start checking from (inclusive)

Return
Int	the index of the previous clear bit, or -1 if there is no such bit

Exceptions
java.lang.IndexOutOfBoundsException	if the specified index is less than -1

previousSetBit

Added in API level 19

open fun previousSetBit(fromIndex: Int): Int

Returns the index of the nearest bit that is set to true that occurs on or before the specified starting index. If no such bit exists, or if -1 is given as the starting index, then -1 is returned.

To iterate over the true bits in a BitSet, use the following loop:

<code>for (int i = bs.length(); (i = bs.previousSetBit(i-1)) &gt;= 0; ) {
      // operate on index i here
  }</code>

Parameters
fromIndex	Int: the index to start checking from (inclusive)

Return
Int	the index of the previous set bit, or -1 if there is no such bit

Exceptions
java.lang.IndexOutOfBoundsException	if the specified index is less than -1

set

Added in API level 1

open fun set(bitIndex: Int): Unit

Sets the bit at the specified index to true.

Parameters
bitIndex	Int: a bit index

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

set

Added in API level 1

open fun set(
    bitIndex: Int, 
    value: Boolean
): Unit

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

Parameters
bitIndex	Int: a bit index
value	Boolean: a boolean value to set

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

set

Added in API level 1

open fun set(
    fromIndex: Int, 
    toIndex: Int
): Unit

Sets the bits from the specified fromIndex (inclusive) to the specified toIndex (exclusive) to true.

Parameters
fromIndex	Int: index of the first bit to be set
toIndex	Int: index after the last bit to be set

Exceptions
java.lang.IndexOutOfBoundsException	if fromIndex is negative, or toIndex is negative, or fromIndex is larger than toIndex

set

Added in API level 1

open fun set(
    fromIndex: Int, 
    toIndex: Int, 
    value: Boolean
): Unit

Sets the bits from the specified fromIndex (inclusive) to the specified toIndex (exclusive) to the specified value.

Parameters
fromIndex	Int: index of the first bit to be set
toIndex	Int: index after the last bit to be set
value	Boolean: value to set the selected bits to

Exceptions
java.lang.IndexOutOfBoundsException	if fromIndex is negative, or toIndex is negative, or fromIndex is larger than toIndex

size

Added in API level 1

open fun size(): Int

Returns the number of bits of space actually in use by this BitSet to represent bit values. The maximum element in the set is the size - 1st element.

Return
Int	the number of bits currently in this bit set

stream

Added in API level 24

open fun stream(): IntStream!

Returns a stream of indices for which this BitSet contains a bit in the set state. The indices are returned in order, from lowest to highest. The size of the stream is the number of bits in the set state, equal to the value returned by the cardinality() method.

The stream binds to this bit set when the terminal stream operation commences (specifically, the spliterator for the stream is late-binding). If the bit set is modified during that operation then the result is undefined.

Return
IntStream!	a stream of integers representing set indices

toByteArray

Added in API level 19

open fun toByteArray(): ByteArray!

Returns a new byte array containing all the bits in this bit set.

More precisely, if
byte[] bytes = s.toByteArray();
then bytes.length == (s.length()+7)/8 and
s.get(n) == ((bytes[n/8] & (1<<(n%8))) != 0)
for all n < 8 * bytes.length.

Return
ByteArray!	a byte array containing a little-endian representation of all the bits in this bit set

toLongArray

Added in API level 19

open fun toLongArray(): LongArray!

Returns a new long array containing all the bits in this bit set.

More precisely, if
long[] longs = s.toLongArray();
then longs.length == (s.length()+63)/64 and
s.get(n) == ((longs[n/64] & (1L<<(n%64))) != 0)
for all n < 64 * longs.length.

Return
LongArray!	a long array containing a little-endian representation of all the bits in this bit set

toString

Added in API level 1

open fun toString(): String

Returns a string representation of this bit set. For every index for which this BitSet 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.

Example:

BitSet drPepper = new BitSet();

Now drPepper.toString() returns "{}".

drPepper.set(2);

Now drPepper.toString() returns "{2}".

drPepper.set(4);
  drPepper.set(10);

Now drPepper.toString() returns "{2, 4, 10}".

Return
String	a string representation of this bit set

valueOf

Added in API level 19

open static fun valueOf(bytes: ByteArray!): BitSet!

Returns a new bit set containing all the bits in the given byte array.

More precisely,
BitSet.valueOf(bytes).get(n) == ((bytes[n/8] & (1<<(n%8))) != 0)
for all n < 8 * bytes.length.

This method is equivalent to BitSet.valueOf(ByteBuffer.wrap(bytes)).

Parameters
bytes	ByteArray!: a byte array containing a little-endian representation of a sequence of bits to be used as the initial bits of the new bit set

Return
BitSet!	a BitSet containing all the bits in the byte array

valueOf

Added in API level 19

open static fun valueOf(bb: ByteBuffer!): BitSet!

Returns a new bit set containing all the bits in the given byte buffer between its position and limit.

More precisely,
BitSet.valueOf(bb).get(n) == ((bb.get(bb.position()+n/8) & (1<<(n%8))) != 0)
for all n < 8 * bb.remaining().

The byte buffer is not modified by this method, and no reference to the buffer is retained by the bit set.

Parameters
bb	ByteBuffer!: a byte buffer containing a little-endian representation of a sequence of bits between its position and limit, to be used as the initial bits of the new bit set

Return
BitSet!	a BitSet containing all the bits in the buffer in the specified range

valueOf

Added in API level 19

open static fun valueOf(lb: LongBuffer!): BitSet!

Returns a new bit set containing all the bits in the given long buffer between its position and limit.

More precisely,
BitSet.valueOf(lb).get(n) == ((lb.get(lb.position()+n/64) & (1L<<(n%64))) != 0)
for all n < 64 * lb.remaining().

The long buffer is not modified by this method, and no reference to the buffer is retained by the bit set.

Parameters
lb	LongBuffer!: a long buffer containing a little-endian representation of a sequence of bits between its position and limit, to be used as the initial bits of the new bit set

Return
BitSet!	a BitSet containing all the bits in the buffer in the specified range

valueOf

Added in API level 19

open static fun valueOf(longs: LongArray!): BitSet!

Returns a new bit set containing all the bits in the given long array.

More precisely,
BitSet.valueOf(longs).get(n) == ((longs[n/64] & (1L<<(n%64))) != 0)
for all n < 64 * longs.length.

This method is equivalent to BitSet.valueOf(LongBuffer.wrap(longs)).

Parameters
longs	LongArray!: a long array containing a little-endian representation of a sequence of bits to be used as the initial bits of the new bit set

Return
BitSet!	a BitSet containing all the bits in the long array

xor

Added in API level 1

open fun xor(set: BitSet!): Unit

Performs a logical XOR of this bit set with the bit set argument. This bit set is modified so that a bit in it has the value true if and only if one of the following statements holds:

• The bit initially has the value true, and the corresponding bit in the argument has the value false.
• The bit initially has the value false, and the corresponding bit in the argument has the value true.

Parameters
set	BitSet!: a bit set