org.apache.derby.iapi.util

Class JBitSet

java.lang.Object

org.apache.derby.iapi.util.JBitSet

public final class JBitSet
extends java.lang.Object

JBitSet is a wrapper class for BitSet. It is a fixed length implementation which can be extended via the grow() method. It provides additional methods to manipulate BitSets. NOTE: JBitSet was driven by the (current and perceived) needs of the optimizer, but placed in the util package since it is not specific to query trees.. NOTE: java.util.BitSet is final, so we must provide a wrapper class which includes a BitSet member in order to extend the functionality. We want to make it look like JBitSet extends BitSet, so we need to provide wrapper methods for all of BitSet's methods.

Constructor Summary

Constructors

Constructor and Description
JBitSet(int size) Construct a JBitSet of the specified size.

Method Summary

Modifier and Type	Method and Description
void	and(JBitSet set)
void	clear(int bitIndex)
void	clearAll() Clear all of the bits in this JBitSet
java.lang.Object	clone()
boolean	contains(JBitSet jBitSet) Test to see if one JBitSet contains another one of the same size.
boolean	equals(java.lang.Object obj)
boolean	get(int bitIndex)
int	getFirstSetBit() Get the first set bit (starting at index 0) from a JBitSet.
void	grow(int newSize) Grow an existing JBitSet to the specified size.
int	hashCode()
boolean	hasSingleBitSet() See of a JBitSet has exactly 1 bit set.
void	or(JBitSet set)
void	set(int bitIndex)
void	setTo(JBitSet sourceBitSet) Set the BitSet to have the exact same bits set as the parameter's BitSet.
int	size() Return the size of bitSet
java.lang.String	toString()
void	xor(JBitSet set)

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

JBitSet

public JBitSet(int size)

Construct a JBitSet of the specified size.

Parameters:

size - The number of bits in the JBitSet.

Method Detail

setTo

public void setTo(JBitSet sourceBitSet)

Set the BitSet to have the exact same bits set as the parameter's BitSet.

Parameters:

sourceBitSet - The JBitSet to copy.

contains

public boolean contains(JBitSet jBitSet)

Test to see if one JBitSet contains another one of the same size.

Parameters:

jBitSet - JBitSet that we want to know if it is a subset of current JBitSet

Returns:

boolean Whether or not jBitSet is a subset.

hasSingleBitSet

public boolean hasSingleBitSet()

See of a JBitSet has exactly 1 bit set.

Returns:

boolean Whether or not JBitSet has a single bit set.

getFirstSetBit

public int getFirstSetBit()

Get the first set bit (starting at index 0) from a JBitSet.

Returns:

int Index of first set bit, -1 if none set.

grow

public void grow(int newSize)

Grow an existing JBitSet to the specified size.

Parameters:

newSize - The new size

clearAll

public void clearAll()

Clear all of the bits in this JBitSet

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

clone

public java.lang.Object clone()

Overrides:

clone in class java.lang.Object

get

public boolean get(int bitIndex)

set

public void set(int bitIndex)

clear

public void clear(int bitIndex)

and

public void and(JBitSet set)

or

public void or(JBitSet set)

xor

public void xor(JBitSet set)

size

public int size()

Return the size of bitSet

Returns:

int Size of bitSet