* #### BitSet
public BitSet()
Creates a new bit set. All bits are initially `false`.
* #### BitSet
public BitSet(int nbits)
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` \- the initial size of the bit set
Throws:
`[NegativeArraySizeException](../../java/lang/NegativeArraySizeException.html "class in java.lang")` \- if the specified initial size is negative
Method Detail
* #### valueOf
public static [BitSet](../../java/util/BitSet.html "class in java.util") valueOf(long[] longs)
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` \- 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
Returns:
a `BitSet` containing all the bits in the long array
Since:
1.7
* #### valueOf
public static [BitSet](../../java/util/BitSet.html "class in java.util") valueOf([LongBuffer](../../java/nio/LongBuffer.html "class in java.nio") lb)
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` \- 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
Returns:
a `BitSet` containing all the bits in the buffer in the specified range
Since:
1.7
* #### valueOf
public static [BitSet](../../java/util/BitSet.html "class in java.util") valueOf(byte[] bytes)
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` \- 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
Returns:
a `BitSet` containing all the bits in the byte array
Since:
1.7
* #### valueOf
public static [BitSet](../../java/util/BitSet.html "class in java.util") valueOf([ByteBuffer](../../java/nio/ByteBuffer.html "class in java.nio") bb)
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` \- 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
Returns:
a `BitSet` containing all the bits in the buffer in the specified range
Since:
1.7
* #### toByteArray
public byte[] toByteArray()
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`.
Returns:
a byte array containing a little-endian representation of all the bits in this bit set
Since:
1.7
* #### toLongArray
public long[] toLongArray()
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`.
Returns:
a long array containing a little-endian representation of all the bits in this bit set
Since:
1.7
* #### flip
public void 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
Throws:
`[IndexOutOfBoundsException](../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- if the specified index is negative
Since:
1.4
* #### flip
public void flip(int fromIndex,
int toIndex)
Sets each bit from the specified `fromIndex` (inclusive) to the specified `toIndex` (exclusive) to the complement of its current value.
Parameters:
`fromIndex` \- index of the first bit to flip
`toIndex` \- index after the last bit to flip
Throws:
`[IndexOutOfBoundsException](../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- if `fromIndex` is negative, or `toIndex` is negative, or `fromIndex` is larger than `toIndex`
Since:
1.4
* #### set
public void set(int bitIndex)
Sets the bit at the specified index to `true`.
Parameters:
`bitIndex` \- a bit index
Throws:
`[IndexOutOfBoundsException](../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- if the specified index is negative
Since:
1.0
* #### 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:
`[IndexOutOfBoundsException](../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- if the specified index is negative
Since:
1.4
* #### set
public void set(int fromIndex,
int toIndex)
Sets the bits from the specified `fromIndex` (inclusive) to the specified `toIndex` (exclusive) to `true`.
Parameters:
`fromIndex` \- index of the first bit to be set
`toIndex` \- index after the last bit to be set
Throws:
`[IndexOutOfBoundsException](../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- if `fromIndex` is negative, or `toIndex` is negative, or `fromIndex` is larger than `toIndex`
Since:
1.4
* #### set
public void set(int fromIndex,
int toIndex,
boolean value)
Sets the bits from the specified `fromIndex` (inclusive) to the specified `toIndex` (exclusive) to the specified value.
Parameters:
`fromIndex` \- index of the first bit to be set
`toIndex` \- index after the last bit to be set
`value` \- value to set the selected bits to
Throws:
`[IndexOutOfBoundsException](../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- if `fromIndex` is negative, or `toIndex` is negative, or `fromIndex` is larger than `toIndex`
Since:
1.4
* #### clear
public void clear(int bitIndex)
Sets the bit specified by the index to `false`.
Parameters:
`bitIndex` \- the index of the bit to be cleared
Throws:
`[IndexOutOfBoundsException](../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- if the specified index is negative
Since:
1.0
* #### clear
public void clear(int fromIndex,
int toIndex)
Sets the bits from the specified `fromIndex` (inclusive) to the specified `toIndex` (exclusive) to `false`.
Parameters:
`fromIndex` \- index of the first bit to be cleared
`toIndex` \- index after the last bit to be cleared
Throws:
`[IndexOutOfBoundsException](../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- if `fromIndex` is negative, or `toIndex` is negative, or `fromIndex` is larger than `toIndex`
Since:
1.4
* #### clear
public void clear()
Sets all of the bits in this BitSet to `false`.
Since:
1.4
* #### 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 in this `BitSet`; otherwise, the result is `false`.
Parameters:
`bitIndex` \- the bit index
Returns:
the value of the bit with the specified index
Throws:
`[IndexOutOfBoundsException](../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- if the specified index is negative
* #### get
public [BitSet](../../java/util/BitSet.html "class in java.util") get(int fromIndex,
int toIndex)
Returns a new `BitSet` composed of bits from this `BitSet` from `fromIndex` (inclusive) to `toIndex` (exclusive).
Parameters:
`fromIndex` \- index of the first bit to include
`toIndex` \- index after the last bit to include
Returns:
a new `BitSet` from a range of this `BitSet`
Throws:
`[IndexOutOfBoundsException](../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- if `fromIndex` is negative, or `toIndex` is negative, or `fromIndex` is larger than `toIndex`
Since:
1.4
* #### 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 in a `BitSet`, use the following loop:
`
for (int i = bs.nextSetBit(0); i >= 0; i = bs.nextSetBit(i+1)) {
// operate on index i here
if (i == Integer.MAX_VALUE) {
break; // or (i+1) would overflow
}
}`
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:
`[IndexOutOfBoundsException](../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- if the specified index is negative
Since:
1.4
* #### 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:
`[IndexOutOfBoundsException](../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- if the specified index is negative
Since:
1.4
* #### previousSetBit
public int previousSetBit(int fromIndex)
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:
`
for (int i = bs.length(); (i = bs.previousSetBit(i-1)) >= 0; ) {
// operate on index i here
}`
Parameters:
`fromIndex` \- the index to start checking from (inclusive)
Returns:
the index of the previous set bit, or `-1` if there is no such bit
Throws:
`[IndexOutOfBoundsException](../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- if the specified index is less than `-1`
Since:
1.7
* #### previousClearBit
public int previousClearBit(int fromIndex)
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` \- the index to start checking from (inclusive)
Returns:
the index of the previous clear bit, or `-1` if there is no such bit
Throws:
`[IndexOutOfBoundsException](../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- if the specified index is less than `-1`
Since:
1.7
* #### length
public int length()
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.
Returns:
the logical size of this `BitSet`
Since:
1.2
* #### isEmpty
public boolean isEmpty()
Returns true if this `BitSet` contains no bits that are set to `true`.
Returns:
boolean indicating whether this `BitSet` is empty
Since:
1.4
* #### intersects
public boolean intersects([BitSet](../../java/util/BitSet.html "class in java.util") set)
Returns true if the specified `BitSet` has any bits set to`true` that are also set to `true` in this `BitSet`.
Parameters:
`set` \- `BitSet` to intersect with
Returns:
boolean indicating whether this `BitSet` intersects the specified `BitSet`
Since:
1.4
* #### cardinality
public int cardinality()
Returns the number of bits set to `true` in this `BitSet`.
Returns:
the number of bits set to `true` in this `BitSet`
Since:
1.4
* #### and
public void and([BitSet](../../java/util/BitSet.html "class in java.util") set)
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` \- a bit set
* #### or
public void or([BitSet](../../java/util/BitSet.html "class in java.util") set)
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` \- a bit set
* #### xor
public void xor([BitSet](../../java/util/BitSet.html "class in java.util") set)
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` \- a bit set
* #### andNot
public void andNot([BitSet](../../java/util/BitSet.html "class in java.util") set)
Clears all of the bits in this `BitSet` whose corresponding bit is set in the specified `BitSet`.
Parameters:
`set` \- the `BitSet` with which to mask this`BitSet`
Since:
1.2
* #### hashCode
public int hashCode()
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:
`
public int hashCode() {
long h = 1234;
long[] words = toLongArray();
for (int i = words.length; --i >= 0; )
h ^= words[i] * (i + 1);
return (int)((h >> 32) ^ h);
}`
Note that the hash code changes if the set of bits is altered.
Overrides:
`[hashCode](../../java/lang/Object.html#hashCode%28%29)` in class `[Object](../../java/lang/Object.html "class in java.lang")`
Returns:
the hash code value for this bit set
See Also:
[Object.equals(java.lang.Object)](../../java/lang/Object.html#equals%28java.lang.Object%29), [System.identityHashCode(java.lang.Object)](../../java/lang/System.html#identityHashCode%28java.lang.Object%29)
* #### size
public int size()
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.
Returns:
the number of bits currently in this bit set
* #### equals
public boolean equals([Object](../../java/lang/Object.html "class in java.lang") obj)
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.
Overrides:
`[equals](../../java/lang/Object.html#equals%28java.lang.Object%29)` in class `[Object](../../java/lang/Object.html "class in java.lang")`
Parameters:
`obj` \- the object to compare with
Returns:
`true` if the objects are the same;`false` otherwise
See Also:
[size()](../../java/util/BitSet.html#size%28%29)
* #### clone
public [Object](../../java/lang/Object.html "class in java.lang") clone()
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.
Overrides:
`[clone](../../java/lang/Object.html#clone%28%29)` in class `[Object](../../java/lang/Object.html "class in java.lang")`
Returns:
a clone of this bit set
See Also:
[size()](../../java/util/BitSet.html#size%28%29)
* #### toString
public [String](../../java/lang/String.html "class in java.lang") toString()
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}`".
Overrides:
`[toString](../../java/lang/Object.html#toString%28%29)` in class `[Object](../../java/lang/Object.html "class in java.lang")`
Returns:
a string representation of this bit set
* #### stream
public [IntStream](../../java/util/stream/IntStream.html "interface in java.util.stream") stream()
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()](../../java/util/BitSet.html#cardinality%28%29) method.
The stream binds to this bit set when the terminal stream operation commences (specifically, the spliterator for the stream is[_late-binding_](Spliterator.html#binding)). If the bit set is modified during that operation then the result is undefined.
Returns:
a stream of integers representing set indices
Since:
1.8