BitSet JDK 1.6)

public void and (BitSet set)

Performs a logical AND of this target bit set with the argument bit 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.

public void andNot (BitSet set)

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

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

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.
Returns: the number of bits set to true in this BitSet.
Since: 1.4

public void clear ()

Sets all of the bits in this BitSet to false.

Sets all of the bits in this BitSet to false.
Since: 1.4

public void clear (int bitIndex)

Sets the bit specified by the index to false.

Sets the bit specified by the index to false.
Parameters:
- bitIndex - the index of the bit to be cleared.
Throws:
- IndexOutOfBoundsException - if the specified index is negative.
Since: JDK1.0

public void clear (int fromIndex, int toIndex)

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

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 - if fromIndex is negative, or toIndex is negative, or fromIndex is larger than toIndex.
Since: 1.4

public Object clone ()

Cloning this BitSet produces a new BitSet that is equal to it.

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 the clone method of Object.
Returns: a clone of this bit set.
See Also: BitSet.size(),

public boolean equals (Object obj)

Compares this object against the specified object.

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 the equals method of Object.
Returns: true if the objects are the same; false otherwise.
Parameters:
- obj - the object to compare with.
See Also: BitSet.size(),

public void flip (int bitIndex)

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

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.

public boolean get (int bitIndex)

Returns the value of the bit with the specified index.

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.
Returns: the value of the bit with the specified index.
Parameters:
- bitIndex - the bit index.
Throws:
- IndexOutOfBoundsException - if the specified index is negative.

public BitSet get (int fromIndex, int toIndex)

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

public int hashCode ()

Returns a hash code value for this bit set.

Returns a hash code value for this bit set. The hash code depends only on which bits have been set within this BitSet. The algorithm used to compute it may be described as follows.

Suppose the bits in the BitSet were to be stored in an array of long integers called, say, words, in such a manner that bit k is set in the BitSet (for nonnegative values of k) if and only if the expression

((k>>6) < words.length) && ((words[k>>6] & (1L << (bit & 0x3F))) != 0)

is true. Then the following definition of the hashCode method would be a correct implementation of the actual algorithm:

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

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

Overrides the hashCode method of Object.
Returns: a hash code value for this bit set.

public boolean intersects (BitSet set)

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

Returns true if the specified BitSet has any bits set to
true that are also set to true in this
BitSet.
Returns: boolean indicating whether this BitSet intersects the specified BitSet.
Parameters:
- set - BitSet to intersect with
Since: 1.4

public boolean isEmpty ()

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

Returns true if this BitSet contains no bits that are set
to true.
Returns: boolean indicating whether this BitSet is empty.
Since: 1.4

public int length ()

Returns the "logical size" of this BitSet: the index of the highest set bit in the BitSet plus one.

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

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.

Returns the index of the first bit that is set to false
that occurs on or after the specified starting index.
Returns: the index of the next clear bit.
Parameters:
- fromIndex - the index to start checking from (inclusive).
Throws:
- IndexOutOfBoundsException - if the specified index is negative.
Since: 1.4

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.

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
 }

Returns: the index of the next set bit.
Parameters:
- fromIndex - the index to start checking from (inclusive).
Throws:
- IndexOutOfBoundsException - if the specified index is negative.
Since: 1.4

public void or (BitSet set)

Performs a logical OR of this bit set with the bit set argument.

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.

public void set (int bitIndex)

Sets the bit at the specified index to true.

Sets the bit at the specified index to true.
Parameters:
- bitIndex - a bit index.
Throws:
- IndexOutOfBoundsException - if the specified index is negative.
Since: JDK1.0

public void set (int bitIndex, boolean value)

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

public void set (int fromIndex, int toIndex)

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

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 - if fromIndex is negative, or toIndex is negative, or fromIndex is larger than toIndex.
Since: 1.4

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.

public int size ()

Returns the number of bits of space actually in use by this BitSet to represent bit values.

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.

public String toString ()

Returns a string representation of this bit set.

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.

Overrides the toString method of Object.

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}".
Returns: a string representation of this bit set.

public void xor (BitSet set)

Performs a logical XOR of this bit set with the bit set argument.

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.