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Class BitSet
java.lang.Object └ java.util.BitSet
Implemented Interfaces:
public class BitSet implements Cloneable, Serializable
This class implements a vector of bits that grows as needed. Each
component of the bit set has a
Author: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.
Arthur van HoffMichael McCloskey
Version:1.60, 02/19/04
Since:JDK1.0
Constructors
public | BitSet () | |
Creates a new bit set. All bits are initially false. |
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. |
Methods
void | and (BitSet 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. |
void | andNot (BitSet set) | |
Clears all of the bits in this BitSet whose corresponding bit is set in the specified BitSet. |
int | cardinality () | |
Returns the number of bits set to true in this BitSet. |
void | clear (int bitIndex) | |
Sets the bit specified by the index to false. |
void | clear (int fromIndex, int toIndex) | |
Sets the bits from the specified fromIndex(inclusive) to the specified toIndex(exclusive) to false. |
void | clear () | |
Sets all of the bits in this BitSet to false. |
| 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 and the same current size. Overrides the clone method of Object. |
boolean | equals (Object 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) ... more > |
void | flip (int bitIndex) | |
Sets the bit at the specified index to the complement of its current value. |
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. |
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. |
| get (int fromIndex, int toIndex) | ||
Returns a new BitSet composed of bits from this BitSet from fromIndex(inclusive) to toIndex(exclusive). |
int | hashCode () | |
Returns a hash code value for this bit set. The has 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, bits, i ... more > |
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. |
boolean | isEmpty () | |
Returns true if this BitSet contains no bits that are set to true. |
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. |
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. 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)) { / ... more > |
void | or (BitSet 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. |
void | 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. |
void | set (int fromIndex, int toIndex) | |
Sets the bits from the specified fromIndex(inclusive) to the specified toIndex(exclusive) to true. |
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. |
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. |
| 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 ... more > |
void | xor (BitSet 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 va ... more > |
Inherited methods
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