Class SparseBitSet
- All Implemented Interfaces:
Serializable
,Cloneable
boolean
value. The values of a
SparseBitSet
are indexed by non-negative integers.
Individual indexed values may be examined, set, cleared, or modified by
logical operations. One SparseBitSet
or logical value may be
used to modify the contents of (another) SparseBitSet
through
logical AND, logical inclusive OR, logical exclusive
OR, and And NOT operations over all or part of the bit sets.
All values in a bit set initially have the value false
.
Every bit set has a current size, which is the number of bits of space nominally in use by the bit set from the first set bit to just after the last set bit. The length of the bit set effectively tells the position available after the last bit of the SparseBitSet.
The maximum cardinality of a SparseBitSet
is
Integer.MAX_VALUE
, which means the bits of a
SparseBitSet
are labelled
0
.. Integer.MAX_VALUE − 1
.
After the last set bit of a SparseBitSet
, any attempt to find
a subsequent bit (nextSetBit()), will return an value of −1.
If an attempt is made to use nextClearBit(), and all the bits are
set from the starting position of the search to the bit labelled
Integer.MAX_VALUE − 1
, then similarly −1
will be returned.
Unless otherwise noted, passing a null parameter to any of the methods in
a SparseBitSet
will result in a
NullPointerException
.
A SparseBitSet
is not safe for multi-threaded use without
external synchronization.
- Since:
- 1.6
- Version:
- 1.0, 2009-03-17
- See Also:
-
Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionprotected static class
This strategy class is used by the setScanner to carry out the a variety of operations on this set, and usually a second set.protected static class
AndNot of two sets.protected static class
And of two sets.protected class
This class holds the values related to various statistics kept about the bit set.protected static class
Clear clears bits in the a set.protected static class
Copies the needed parts of the b set to the a set.protected static class
Equals compares bits in the a set with those in the b set.protected static class
Flip inverts the bits of the a set within the given range.protected static class
Intersect has a true result if any word in the a set has a bit in common with the b set.protected static class
Or of two sets.protected static class
Set creates entries everywhere within the range.static enum
These enumeration values are used as labels for the values in the String created by the statistics() method.protected class
Update the seven statistics that are computed for each set.protected static class
The XOR of level3 blocks is computed. -
Field Summary
FieldsModifier and TypeFieldDescriptionprotected static final SparseBitSet.AndNotStrategy
Word and block andNot strategy.protected static final SparseBitSet.AndStrategy
Word and block and strategy.protected long[][][]
The storage for this SparseBitSet.protected int
For the current size of the bits array, this is the maximum possible length of the bit set, i.e., the index of the last possible bit, plus one.protected SparseBitSet.Cache
Holds reference to the cache of statistics values computed by the UpdateStrategyprotected static final SparseBitSet.ClearStrategy
Word and block clear strategy.protected int
This value controls for format of the toString() output.(package private) static int
The compaction count default.protected static final SparseBitSet.CopyStrategy
Word and block copy strategy.protected SparseBitSet.EqualsStrategy
Word and block equals strategy.protected static final SparseBitSet.FlipStrategy
Word and block flip strategy.protected static final int
The number of bits in a positive integer, and the size of permitted index of a bit in the bit set.protected static SparseBitSet.IntersectsStrategy
Word and block intersects strategy.protected static final int
LENGTH2 is the number of entries in the any level2 area.protected static final int
LENGTH2_SIZE is maximum index of a LEVEL2 page.protected static final int
LENGTH3 is the number of entries in the any level3 block.protected static final int
LENGTH3_SIZE is maximum index of a LEVEL3 page.protected static final int
The number of bits in a long value.protected static final int
LENGTH4_SIZE is maximum index of a bit in a LEVEL4 word.protected static final int
LEVEL1 is the number of bits of the level1 address.protected static final int
LEVEL2 is the number of bits of the level2 address.protected static final int
LEVEL3 is the number of bits of the level3 address.protected static final int
The label (index) of a bit in the bit set is essentially broken into 4 "levels".protected static final int
MASK2 is the mask to extract the LEVEL2 address from a word index (after shifting by SHIFT3 and SHIFT2).protected static final int
MASK3 is the mask to extract the LEVEL3 address from a word index (after shifting by SHIFT3).protected static final int
MAX_LENGTH1 is the maximum number of entries in the level1 set array.protected static final SparseBitSet.OrStrategy
Word and block or strategy.private static final long
serialVersionUIDprotected static final SparseBitSet.SetStrategy
Word and block set strategy.protected static final int
SHIFT1 is the shift to bring the level1 address (from the word index) to the right end (i.e., after shifting by SHIFT3).protected static final int
SHIFT2 is the shift to bring the level2 address (from the word index) to the right end (i.e., after shifting by SHIFT3).protected static final int
The shift to create the word index.protected long[]
A spare level 3 block is kept for use when scanning.protected static final int
UNIT is the greatest number of bits that can be held in one level1 entry.protected SparseBitSet.UpdateStrategy
Word and block update strategy.protected static final SparseBitSet.XorStrategy
Word and block xor strategy.(package private) static final long[]
An empty level 3 block is kept for use when scanning. -
Constructor Summary
ConstructorsModifierConstructorDescriptionConstructs an empty bit set with the default initial size.SparseBitSet
(int nbits) Creates a bit set whose initial size is large enough to efficiently represent bits with indices in the range0
through at leastnbits-1
.protected
SparseBitSet
(int capacity, int compactionCount) Constructor for a new (sparse) bit set. -
Method Summary
Modifier and TypeMethodDescriptionvoid
and
(int i, boolean value) Performs a logical AND of the addressed target bit with the argument value.void
and
(int i, int j, SparseBitSet b) Performs a logical AND of this target bit set with the argument bit set within the given range of bits.void
and
(SparseBitSet b) Performs a logical AND of this target bit set with the argument bit set.static SparseBitSet
and
(SparseBitSet a, SparseBitSet b) Performs a logical AND of the two givenSparseBitSet
s.void
andNot
(int i, boolean value) Performs a logical AndNOT of the addressed target bit with the argument value.void
andNot
(int i, int j, SparseBitSet b) Performs a logical AndNOT of this target bit set with the argument bit set within the given range of bits.void
Performs a logical AndNOT of this target bit set with the argument bit set.static SparseBitSet
andNot
(SparseBitSet a, SparseBitSet b) Creates a bit set from thie firstSparseBitSet
whose corresponding bits are cleared by the set bits of the secondSparseBitSet
.int
Returns the number of bits set totrue
in thisSparseBitSet
.void
clear()
Sets all of the bits in thisSparseBitSet
tofalse
.void
clear
(int i) Sets the bit at the specified index tofalse
.void
clear
(int i, int j) Sets the bits from the specifiedi
(inclusive) to the specifiedj
(exclusive) tofalse
.clone()
Cloning thisSparseBitSet
produces a newSparseBitSet
that is equal() to it.protected final void
Intializes all the additional objects required for correct operation.boolean
Compares this object against the specified object.void
flip
(int i) Sets the bit at the specified index to the complement of its current value.void
flip
(int i, int j) Sets each bit from the specifiedi
(inclusive) to the specifiedj
(exclusive) to the complement of its current value.boolean
get
(int i) Returns the value of the bit with the specified index.get
(int i, int j) Returns a newSparseBitSet
composed of bits from thisSparseBitSet
fromi
(inclusive) toj
(exclusive).int
hashCode()
Returns a hash code value for this bit set.boolean
intersects
(int i, int j, SparseBitSet b) Returns true if the specifiedSparseBitSet
has any bits within the given rangei
(inclusive) toj
(exclusive) set totrue
that are also set totrue
in the same range of thisSparseBitSet
.boolean
Returns true if the specifiedSparseBitSet
has any bits set totrue
that are also set totrue
in thisSparseBitSet
.boolean
isEmpty()
Returns true if thisSparseBitSet
contains no bits that are set totrue
.int
length()
Returns the "logical length" of thisSparseBitSet
: the index of the highest set bit in theSparseBitSet
plus one.int
nextClearBit
(int i) Returns the index of the first bit that is set tofalse
that occurs on or after the specified starting index.int
nextSetBit
(int i) Returns the index of the first bit that is set totrue
that occurs on or after the specified starting index.protected final void
nullify
(int start) Clear out a part of the set array with nulls, from the given start to the end of the array.void
or
(int i, boolean value) Performs a logical OR of the addressed target bit with the argument value.void
or
(int i, int j, SparseBitSet b) Performs a logical OR of the addressed target bit with the argument value within the given range.void
or
(SparseBitSet b) Performs a logical OR of this bit set with the bit set argument.static SparseBitSet
or
(SparseBitSet a, SparseBitSet b) Performs a logical OR of the two givenSparseBitSet
s.int
previousClearBit
(int i) Returns the index of the nearest bit that is set tofalse
that occurs on or before the specified starting index.int
previousSetBit
(int i) Returns the index of the nearest bit that is set totrue
that occurs on or before the specified starting index.private void
Reconstitute theSparseBitSet
instance from a stream (i.e., deserialize it).protected final void
resize
(int index) Resize the bit array.void
set
(int i) Sets the bit at the specified index.void
set
(int i, boolean value) Sets the bit at the specified index to the specified value.void
set
(int i, int j) Sets the bits from the specifiedi
(inclusive) to the specifiedj
(exclusive) totrue
.void
set
(int i, int j, boolean value) Sets the bits from the specifiedi
(inclusive) to the specifiedj
(exclusive) to the specified value.protected final void
setScanner
(int i, int j, SparseBitSet b, SparseBitSet.AbstractStrategy op) Scans over the bit set (and a second bit set if part of the operation) are all performed by this method.int
size()
Returns the number of bits of space nominally in use by thisSparseBitSet
to represent bit values.Convenience method for statistics if the individual results are not needed.statistics
(String[] values) Determine, and create a String with the bit set statistics.protected final void
The entirety of the bit set is examined, and the various statistics of the bit set (size, length, cardinality, hashCode, etc.) are computed.protected static void
throwIndexOutOfBoundsException
(int i, int j) Throw the exception to indicate a range error.toString()
Returns a string representation of this bit set.void
toStringCompaction
(boolean change) If change istrue
, the current value of the toStringCompaction() value is made the default value for allSparseBitSet
s created from this point onward in this JVM.void
toStringCompaction
(int count) Sequences of set bits longer than this value are shown bytoString()
as a "sub-sequence," in the forma..b
.private void
Save the state of theSparseBitSet
instance to a stream (i.e., serialize it).void
xor
(int i, boolean value) Performs a logical XOR of the addressed target bit with the argument value.void
xor
(int i, int j, SparseBitSet b) Performs a logical XOR of this bit set with the bit set argument within the given range.void
xor
(SparseBitSet b) Performs a logical XOR of this bit set with the bit set argument.static SparseBitSet
xor
(SparseBitSet a, SparseBitSet b) Performs a logical XOR of the two givenSparseBitSet
s.
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Field Details
-
compactionCount
protected transient int compactionCountThis value controls for format of the toString() output.- See Also:
-
compactionCountDefault
static int compactionCountDefaultThe compaction count default. -
bits
protected transient long[][][] bitsThe storage for this SparseBitSet. The ith bit is stored in a word represented by a long value, and is at bit positioni % 64
within that word (where bit position 0 refers to the least significant bit and 63 refers to the most significant bit).The words are organized into blocks, and the blocks are accessed by two additional levels of array indexing.
-
bitsLength
protected transient int bitsLengthFor the current size of the bits array, this is the maximum possible length of the bit set, i.e., the index of the last possible bit, plus one. Note: this not the value returned by length().- See Also:
-
LENGTH4
protected static final int LENGTH4The number of bits in a long value.- See Also:
-
INDEX_SIZE
protected static final int INDEX_SIZEThe number of bits in a positive integer, and the size of permitted index of a bit in the bit set.- See Also:
-
LEVEL4
protected static final int LEVEL4The label (index) of a bit in the bit set is essentially broken into 4 "levels". Respectively (from the least significant end), level4, the address within word, the address within a level3 block, the address within a level2 area, and the level1 address of that area within the set. LEVEL4 is the number of bits of the level4 address (number of bits need to address the bits in a long)- See Also:
-
LEVEL3
protected static final int LEVEL3LEVEL3 is the number of bits of the level3 address.- See Also:
-
LEVEL2
protected static final int LEVEL2LEVEL2 is the number of bits of the level2 address.- See Also:
-
LEVEL1
protected static final int LEVEL1LEVEL1 is the number of bits of the level1 address.- See Also:
-
MAX_LENGTH1
protected static final int MAX_LENGTH1MAX_LENGTH1 is the maximum number of entries in the level1 set array.- See Also:
-
LENGTH2
protected static final int LENGTH2LENGTH2 is the number of entries in the any level2 area.- See Also:
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LENGTH3
protected static final int LENGTH3LENGTH3 is the number of entries in the any level3 block.- See Also:
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SHIFT3
protected static final int SHIFT3The shift to create the word index. (I.e., move it to the right end)- See Also:
-
MASK3
protected static final int MASK3MASK3 is the mask to extract the LEVEL3 address from a word index (after shifting by SHIFT3).- See Also:
-
SHIFT2
protected static final int SHIFT2SHIFT2 is the shift to bring the level2 address (from the word index) to the right end (i.e., after shifting by SHIFT3).- See Also:
-
UNIT
protected static final int UNITUNIT is the greatest number of bits that can be held in one level1 entry. That is, bits per word by words per level3 block by blocks per level2 area.- See Also:
-
MASK2
protected static final int MASK2MASK2 is the mask to extract the LEVEL2 address from a word index (after shifting by SHIFT3 and SHIFT2).- See Also:
-
SHIFT1
protected static final int SHIFT1SHIFT1 is the shift to bring the level1 address (from the word index) to the right end (i.e., after shifting by SHIFT3).- See Also:
-
LENGTH2_SIZE
protected static final int LENGTH2_SIZELENGTH2_SIZE is maximum index of a LEVEL2 page.- See Also:
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LENGTH3_SIZE
protected static final int LENGTH3_SIZELENGTH3_SIZE is maximum index of a LEVEL3 page.- See Also:
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LENGTH4_SIZE
protected static final int LENGTH4_SIZELENGTH4_SIZE is maximum index of a bit in a LEVEL4 word.- See Also:
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cache
Holds reference to the cache of statistics values computed by the UpdateStrategy- See Also:
-
spare
protected transient long[] spareA spare level 3 block is kept for use when scanning. When a target block is needed, and there is not already one in the bit set, the spare is provided. If non-zero values are placed into this block, it is moved to the resulting set, and a new spare is acquired. Note: a new spare needs to be allocated when the set is cloned (so that the spare is not shared between two sets). -
ZERO_BLOCK
static final long[] ZERO_BLOCKAn empty level 3 block is kept for use when scanning. When a source block is needed, and there is not already one in the corresponding bit set, the ZERO_BLOCK is used (as a read-only block). It is a source of zero values so that code does not have to test for a null level3 block. This is a static block shared everywhere. -
serialVersionUID
private static final long serialVersionUIDserialVersionUID- See Also:
-
andStrategy
Word and block and strategy. -
andNotStrategy
Word and block andNot strategy. -
clearStrategy
Word and block clear strategy. -
copyStrategy
Word and block copy strategy. -
equalsStrategy
Word and block equals strategy. -
flipStrategy
Word and block flip strategy. -
intersectsStrategy
Word and block intersects strategy. -
orStrategy
Word and block or strategy. -
setStrategy
Word and block set strategy. -
updateStrategy
Word and block update strategy. -
xorStrategy
Word and block xor strategy.
-
-
Constructor Details
-
SparseBitSet
Constructor for a new (sparse) bit set. All bits initially are effectivelyfalse
. This is a internal constructor that collects all the needed actions to initialise the bit set.The capacity is taken to be a suggestion for a size of the bit set, in bits. An appropiate table size (a power of two) is then determined and used. The size will be grown as needed to accomodate any bits addressed during the use of the bit set.
- Parameters:
capacity
- a size in terms of bitscompactionCount
- the compactionCount to be inherited (for internal generation)- Throws:
NegativeArraySizeException
- if the specified initial size is negative- Since:
- 1.6
-
SparseBitSet
public SparseBitSet()Constructs an empty bit set with the default initial size. Initially all bits are effectivelyfalse
.- Since:
- 1.6
-
SparseBitSet
Creates a bit set whose initial size is large enough to efficiently represent bits with indices in the range0
through at leastnbits-1
. Initially all bits are effectivelyfalse
.No guarantees are given for how large or small the actual object will be. The setting of bits above the given range is permitted (and will perhaps eventually cause resizing).
- Parameters:
nbits
- the initial provisional length of the SparseBitSet- Throws:
NegativeArraySizeException
- if the specified initial length is negative- Since:
- 1.6
- See Also:
-
-
Method Details
-
and
Performs a logical AND of the addressed target bit with the argument value. This bit set is modified so that the addressed bit has the valuetrue
if and only if it both initially had the valuetrue
and the argument value is alsotrue
.- Parameters:
i
- a bit indexvalue
- a boolean value to AND with that bit- Throws:
IndexOutOfBoundsException
- if the specified index is negative or equal to Integer.MAX_VALUE- Since:
- 1.6
-
and
Performs a logical AND of this target bit set with the argument bit set within the given range of bits. Within the range, this bit set is modified so that each bit in it has the valuetrue
if and only if it both initially had the valuetrue
and the corresponding bit in the bit set argument also had the valuetrue
. Outside the range, this set is not changed.- Parameters:
i
- index of the first bit to be included in the operationj
- index after the last bit to included in the operationb
- a SparseBitSet- Throws:
IndexOutOfBoundsException
- ifi
is negative or equal to Integer.MAX_VALUE, orj
is negative, ori
is larger thanj
- Since:
- 1.6
-
and
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 valuetrue
if and only if it both initially had the valuetrue
and the corresponding bit in the bit set argument also had the valuetrue
.- Parameters:
b
- a SparseBitSet- Since:
- 1.6
-
and
Performs a logical AND of the two givenSparseBitSet
s. The returnedSparseBitSet
is created so that each bit in it has the valuetrue
if and only if both the given sets initially had the corresponding bitstrue
, otherwisefalse
.- Parameters:
a
- a SparseBitSetb
- another SparseBitSet- Returns:
- a new SparseBitSet representing the AND of the two sets
- Since:
- 1.6
-
andNot
public void andNot(int i, boolean value) Performs a logical AndNOT of the addressed target bit with the argument value. This bit set is modified so that the addressed bit has the valuetrue
if and only if it both initially had the valuetrue
and the argument value isfalse
.- Parameters:
i
- a bit indexvalue
- a boolean value to AndNOT with that bit- Throws:
IndexOutOfBoundsException
- if the specified index is negative or equal to Integer.MAX_VALUE- Since:
- 1.6
-
andNot
Performs a logical AndNOT of this target bit set with the argument bit set within the given range of bits. Within the range, this bit set is modified so that each bit in it has the valuetrue
if and only if it both initially had the valuetrue
and the corresponding bit in the bit set argument has the valuefalse
. Outside the range, this set is not changed.- Parameters:
i
- index of the first bit to be included in the operationj
- index after the last bit to included in the operationb
- the SparseBitSet with which to mask this SparseBitSet- Throws:
IndexOutOfBoundsException
- ifi
is negative or equal to Integer.MAX_VALUE, orj
is negative, ori
is larger thanj
- Since:
- 1.6
-
andNot
Performs a logical AndNOT of this target bit set with the argument bit set. This bit set is modified so that each bit in it has the valuetrue
if and only if it both initially had the valuetrue
and the corresponding bit in the bit set argument has the valuefalse
.- Parameters:
b
- the SparseBitSet with which to mask this SparseBitSet- Since:
- 1.6
-
andNot
Creates a bit set from thie firstSparseBitSet
whose corresponding bits are cleared by the set bits of the secondSparseBitSet
. The resulting bit set is created so that a bit in it has the valuetrue
if and only if the corresponding bit in theSparseBitSet
of the first is set, and that same corresponding bit is not set in theSparseBitSet
of the second argument.- Parameters:
a
- a SparseBitSetb
- another SparseBitSet- Returns:
- a new SparseBitSet representing the AndNOT of the two sets
- Since:
- 1.6
-
cardinality
public int cardinality()Returns the number of bits set totrue
in thisSparseBitSet
.- Returns:
- the number of bits set to true in this SparseBitSet
- Since:
- 1.6
-
clear
public void clear(int i) Sets the bit at the specified index tofalse
.- Parameters:
i
- a bit index.- Throws:
IndexOutOfBoundsException
- if the specified index is negative or equal to Integer.MAX_VALUE.- Since:
- 1.6
-
clear
Sets the bits from the specifiedi
(inclusive) to the specifiedj
(exclusive) tofalse
.- Parameters:
i
- index of the first bit to be clearedj
- index after the last bit to be cleared- Throws:
IndexOutOfBoundsException
- ifi
is negative or equal to Integer.MAX_VALUE, orj
is negative, ori
is larger thanj
- Since:
- 1.6
-
clear
public void clear()Sets all of the bits in thisSparseBitSet
tofalse
.- Since:
- 1.6
-
clone
Cloning thisSparseBitSet
produces a newSparseBitSet
that is equal() to it. The clone of the bit set is another bit set that has exactly the same bits set totrue
as this bit set.Note: the actual space allocated to the clone tries to minimise the actual amount of storage allocated to hold the bits, while still trying to keep access to the bits being a rapid as possible. Since the space allocated to a
SparseBitSet
is not normally decreased, replacing a bit set by its clone may be a way of both managing memory consumption and improving the rapidity of access. -
equals
Compares this object against the specified object. The result istrue
if and only if the argument is notnull
and is aSparseBitSet
object that has exactly the same bits set totrue
as this bit set. That is, for every nonnegativei
indexing a bit in the set,((SparseBitSet)obj).get(i) == this.get(i)
must be true. -
flip
public void flip(int i) Sets the bit at the specified index to the complement of its current value.- Parameters:
i
- the index of the bit to flip- Throws:
IndexOutOfBoundsException
- if the specified index is negative or equal to Integer.MAX_VALUE- Since:
- 1.6
-
flip
Sets each bit from the specifiedi
(inclusive) to the specifiedj
(exclusive) to the complement of its current value.- Parameters:
i
- index of the first bit to flipj
- index after the last bit to flip- Throws:
IndexOutOfBoundsException
- ifi
is negative or is equal to Integer.MAX_VALUE, orj
is negative, ori
is larger thanj
- Since:
- 1.6
-
get
public boolean get(int i) Returns the value of the bit with the specified index. The value istrue
if the bit with the indexi
is currently set in thisSparseBitSet
; otherwise, the result isfalse
.- Parameters:
i
- the bit index- Returns:
- the boolean value of the bit with the specified index.
- Throws:
IndexOutOfBoundsException
- if the specified index is negative or equal to Integer.MAX_VALUE- Since:
- 1.6
-
get
Returns a newSparseBitSet
composed of bits from thisSparseBitSet
fromi
(inclusive) toj
(exclusive).- Parameters:
i
- index of the first bit to includej
- index after the last bit to include- Returns:
- a new SparseBitSet from a range of this SparseBitSet
- Throws:
IndexOutOfBoundsException
- ifi
is negative or is equal to Integer.MAX_VALUE, orj
is negative, ori
is larger thanj
- Since:
- 1.6
-
hashCode
public int hashCode()Returns a hash code value for this bit set. The hash code depends only on which bits have been set within thisSparseBitSet
. The algorithm used to compute it may be described as follows.Suppose the bits in the
SparseBitSet
were to be stored in an array oflong
integers called, say,bits
, in such a manner that biti
is set in theSparseBitSet
(for nonnegative values ofi
) if and only if the expression((i>>6) < bits.length) && ((bits[i>>6] & (1L << (bit & 0x3F))) != 0)
is true. Then the following definition of thehashCode
method would be a correct implementation of the actual algorithm:public int hashCode() { long hash = 1234L; for( int i = bits.length; --i >= 0; ) hash ^= bits[i] * (i + 1); return (int)((h >> 32) ^ h); }
Note that the hash code values change if the set of bits is altered. -
intersects
Returns true if the specifiedSparseBitSet
has any bits within the given rangei
(inclusive) toj
(exclusive) set totrue
that are also set totrue
in the same range of thisSparseBitSet
.- Parameters:
i
- index of the first bit to includej
- index after the last bit to includeb
- the SparseBitSet with which to intersect- Returns:
- the boolean indicating whether this SparseBitSet intersects the specified SparseBitSet
- Throws:
IndexOutOfBoundsException
- ifi
is negative or equal to Integer.MAX_VALUE, orj
is negative, ori
is larger thanj
- Since:
- 1.6
-
intersects
Returns true if the specifiedSparseBitSet
has any bits set totrue
that are also set totrue
in thisSparseBitSet
.- Parameters:
b
- a SparseBitSet with which to intersect- Returns:
- boolean indicating whether this SparseBitSet intersects the specified SparseBitSet
- Since:
- 1.6
-
isEmpty
public boolean isEmpty()Returns true if thisSparseBitSet
contains no bits that are set totrue
.- Returns:
- the boolean indicating whether this SparseBitSet is empty
- Since:
- 1.6
-
length
public int length()Returns the "logical length" of thisSparseBitSet
: the index of the highest set bit in theSparseBitSet
plus one. Returns zero if theSparseBitSet
contains no set bits.- Returns:
- the logical length of this SparseBitSet
- Since:
- 1.6
-
nextClearBit
public int nextClearBit(int i) Returns the index of the first bit that is set tofalse
that occurs on or after the specified starting index.- Parameters:
i
- the index to start checking from (inclusive)- Returns:
- the index of the next clear bit, or -1 if there is no such bit
- Throws:
IndexOutOfBoundsException
- if the specified index is negative- Since:
- 1.6
-
nextSetBit
public int nextSetBit(int i) Returns the index of the first bit that is set totrue
that occurs on or after the specified starting index. If no such it exists then -1 is returned.To iterate over the
true
bits in aSparseBitSet sbs
, use the following loop:for( int i = sbbits.nextSetBit(0); i >= 0; i = sbbits.nextSetBit(i+1) ) { // operate on index i here }
- Parameters:
i
- the index to start checking from (inclusive)- Returns:
- the index of the next set bit
- Throws:
IndexOutOfBoundsException
- if the specified index is negative- Since:
- 1.6
-
previousClearBit
public int previousClearBit(int i) Returns the index of the nearest bit that is set tofalse
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:
i
- 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
- if the specified index is less than-1
- Since:
- 1.2
- See Also:
-
previousSetBit
public int previousSetBit(int i) Returns the index of the nearest bit that is set totrue
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:
i
- 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
- if the specified index is less than-1
- Since:
- 1.2
- See Also:
-
or
public void or(int i, boolean value) Performs a logical OR of the addressed target bit with the argument value. This bit set is modified so that the addressed bit has the valuetrue
if and only if it both initially had the valuetrue
or the argument value istrue
.- Parameters:
i
- a bit indexvalue
- a boolean value to OR with that bit- Throws:
IndexOutOfBoundsException
- if the specified index is negative or equal to Integer.MAX_VALUE- Since:
- 1.6
-
or
Performs a logical OR of the addressed target bit with the argument value within the given range. This bit set is modified so that within the range a bit in it has the valuetrue
if and only if it either already had the valuetrue
or the corresponding bit in the bit set argument has the valuetrue
. Outside the range this set is not changed.- Parameters:
i
- index of the first bit to be included in the operationj
- index after the last bit to included in the operationb
- the SparseBitSet with which to perform the OR operation with this SparseBitSet- Throws:
IndexOutOfBoundsException
- ifi
is negative or equal to Integer.MAX_VALUE, orj
is negative, ori
is larger thanj
- Since:
- 1.6
-
or
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 valuetrue
if and only if it either already had the valuetrue
or the corresponding bit in the bit set argument has the valuetrue
.- Parameters:
b
- the SparseBitSet with which to perform the OR operation with this SparseBitSet- Since:
- 1.6
-
or
Performs a logical OR of the two givenSparseBitSet
s. The returnedSparseBitSet
is created so that a bit in it has the valuetrue
if and only if it either had the valuetrue
in the set given by the first arguemetn or had the valuetrue
in the second argument, otherwisefalse
.- Parameters:
a
- a SparseBitSetb
- another SparseBitSet- Returns:
- new SparseBitSet representing the OR of the two sets
- Since:
- 1.6
-
set
public void set(int i) Sets the bit at the specified index.- Parameters:
i
- a bit index- Throws:
IndexOutOfBoundsException
- if the specified index is negative or equal to Integer.MAX_VALUE- Since:
- 1.6
-
set
public void set(int i, boolean value) Sets the bit at the specified index to the specified value.- Parameters:
i
- a bit indexvalue
- a boolean value to set- Throws:
IndexOutOfBoundsException
- if the specified index is negative or equal to Integer.MAX_VALUE- Since:
- 1.6
-
set
Sets the bits from the specifiedi
(inclusive) to the specifiedj
(exclusive) totrue
.- Parameters:
i
- index of the first bit to be setj
- index after the last bit to be se- Throws:
IndexOutOfBoundsException
- ifi
is negative or is equal to Integer.MAX_INT, orj
is negative, ori
is larger thanj
.- Since:
- 1.6
-
set
public void set(int i, int j, boolean value) Sets the bits from the specifiedi
(inclusive) to the specifiedj
(exclusive) to the specified value.- Parameters:
i
- index of the first bit to be setj
- index after the last bit to be setvalue
- to which to set the selected bits- Throws:
IndexOutOfBoundsException
- ifi
is negative or is equal to Integer.MAX_VALUE, orj
is negative, ori
is larger thanj
- Since:
- 1.6
-
size
public int size()Returns the number of bits of space nominally in use by thisSparseBitSet
to represent bit values. The count of bits in the set is the (label of the last set bit) + 1 - (the label of the first set bit).- Returns:
- the number of bits (true and false) nominally in this bit set at this moment
- Since:
- 1.6
-
statistics
Convenience method for statistics if the individual results are not needed.- Returns:
- a String detailing the statistics of the bit set
- Since:
- 1.6
- See Also:
-
statistics
Determine, and create a String with the bit set statistics. The statistics include: Size, Length, Cardinality, Total words (i.e., the total number of 64-bit "words"), Set array length (i.e., the number of references that can be held by the top level array, Level2 areas in use, Level3 blocks in use,, Level2 pool size, Level3 pool size, and the Compaction count.This method is intended for diagnostic use (as it is relatively expensive in time), but can be useful in understanding an application's use of a
SparseBitSet
.- Parameters:
values
- an array for the individual results (if not null)- Returns:
- a String detailing the statistics of the bit set
- Since:
- 1.6
-
toString
Returns a string representation of this bit set. For every index for which thisSparseBitSet
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. If there is a subsequence of set bits longer than the value given by toStringCompaction, the subsequence is represented by the value for the first and the last values, with ".." between them. The individual bits, or the representation of sub-sequences are separated by ", " (a comma and a space) and surrounded by braces, resulting in a compact string showing (a variant of) the usual mathematical notation for a set of integers.
Example (with the default value of 2 for subsequences):SparseBitSet drPepper = new SparseBitSet();
NowdrPepper.toString()
returns "{}
".
drPepper.set(2);
NowdrPepper.toString()
returns "{2}
".
drPepper.set(3, 4); drPepper.set(10);
NowdrPepper.toString()
returns "{2..4, 10}
".
This method is intended for diagnostic use (as it is relatively expensive in time), but can be useful in interpreting problems in an application's use of aSparseBitSet
. -
toStringCompaction
public void toStringCompaction(int count) Sequences of set bits longer than this value are shown bytoString()
as a "sub-sequence," in the forma..b
. Setting this value to zero causes each set bit to be listed individually. The default default value is 2 (which means sequences of three or more bits set are shown as a subsequence, and all other set bits are listed individually).Note: this value will be passed to
SparseBitSet
s that may be created within or as a result of the operations on this bit set, or, for static methods, from the value belonging to the first parameter.- Parameters:
count
- the maximum count of a run of bits that are shown as individual entries in atoString
() conversion. If 0, all bits are shown individually.- Since:
- 1.6
- See Also:
-
toStringCompaction
public void toStringCompaction(boolean change) If change istrue
, the current value of the toStringCompaction() value is made the default value for allSparseBitSet
s created from this point onward in this JVM.- Parameters:
change
- if true, change the default value- Since:
- 1.6
-
xor
public void xor(int i, boolean value) Performs a logical XOR of the addressed target bit with the argument value. This bit set is modified so that the addressed bit has the valuetrue
if and only one of the following statements holds:- The addressed bit initially had the value
true
, and the value of the argument isfalse
. - The bit initially had the value
false
, and the value of the argument istrue
.
- Parameters:
i
- a bit indexvalue
- a boolean value to XOR with that bit- Throws:
IndexOutOfBoundsException
- if the specified index is negative or equal to Integer.MAX_VALUE- Since:
- 1.6
- The addressed bit initially had the value
-
xor
Performs a logical XOR of this bit set with the bit set argument within the given range. This resulting bit set is computed so that a bit within the range in it has the valuetrue
if and only if one of the following statements holds:- The bit initially had the value
true
, and the corresponding bit in the argument set has the valuefalse
. - The bit initially had the value
false
, and the corresponding bit in the argument set has the valuetrue
.
- Parameters:
i
- index of the first bit to be included in the operationj
- index after the last bit to included in the operationb
- the SparseBitSet with which to perform the XOR operation with this SparseBitSet- Throws:
IndexOutOfBoundsException
- ifi
is negative or equal to Integer.MAX_VALUE, orj
is negative, ori
is larger thanj
- Since:
- 1.6
- The bit initially had the value
-
xor
Performs a logical XOR of this bit set with the bit set argument. This resulting bit set is computed so that a bit in it has the valuetrue
if and only if one of the following statements holds:- The bit initially had the value
true
, and the corresponding bit in the argument set has the valuefalse
. - The bit initially had the value
false
, and the corresponding bit in the argument set has the valuetrue
.
- Parameters:
b
- the SparseBitSet with which to perform the XOR operation with thisSparseBitSet- Since:
- 1.6
- The bit initially had the value
-
xor
Performs a logical XOR of the two givenSparseBitSet
s. The resulting bit set is created so that a bit in it has the valuetrue
if and only if one of the following statements holds:- A bit in the first argument has the value
true
, and the corresponding bit in the second argument has the valuefalse
. - A bit in the first argument has the value
false
, and the corresponding bit in the second argument has the valuetrue
.
- Parameters:
a
- a SparseBitSetb
- another SparseBitSet- Returns:
- a new SparseBitSet representing the XOR of the two sets
- Since:
- 1.6
- A bit in the first argument has the value
-
throwIndexOutOfBoundsException
Throw the exception to indicate a range error. TheString
constructed reports all the possible errors in one message.- Parameters:
i
- lower bound for a operationj
- upper bound for a operation- Throws:
IndexOutOfBoundsException
- indicating the range is not valid- Since:
- 1.6
-
constructorHelper
protected final void constructorHelper()Intializes all the additional objects required for correct operation.- Since:
- 1.6
-
nullify
protected final void nullify(int start) Clear out a part of the set array with nulls, from the given start to the end of the array. If the given parameter is beyond the end of the bits array, nothing is changed.- Parameters:
start
- word index at which to start (inclusive)- Since:
- 1.6
-
resize
protected final void resize(int index) Resize the bit array. Moves the entries in the the bits array of this SparseBitSet into an array whose size (which may be larger or smaller) is the given bit size (i.e., includes the bit whose index is one less that the given value). If the new array is smaller, the excess entries in the set array are discarded. If the new array is bigger, it is filled with nulls.- Parameters:
index
- the desired address to be included in the set- Since:
- 1.6
-
setScanner
protected final void setScanner(int i, int j, SparseBitSet b, SparseBitSet.AbstractStrategy op) throws IndexOutOfBoundsException Scans over the bit set (and a second bit set if part of the operation) are all performed by this method. The properties and the operation executed are defined by a given strategy, which must be derived from theAbstractStrategy
. The strategy defines how to operate on a single word, and on whole words that may or may not constitute a full block of words.- Parameters:
i
- the bit (inclusive) at which to start the scanj
- the bit (exclusive) at which to stop the scanb
- a SparseBitSet, if needed, the second SparseBitSet in the operationop
- the AbstractStrategy class defining the operation to be executed- Throws:
IndexOutOfBoundsException
- Since:
- 1.6
- See Also:
-
statisticsUpdate
protected final void statisticsUpdate()The entirety of the bit set is examined, and the various statistics of the bit set (size, length, cardinality, hashCode, etc.) are computed. Level arrays that are empty (i.e., all zero at level 3, all null at level 2) are replaced by null references, ensuring a normalized representation.- Since:
- 1.6
-
writeObject
Save the state of theSparseBitSet
instance to a stream (i.e., serialize it).- Parameters:
s
- the ObjectOutputStream to which to write the serialized object- Throws:
IOException
- if an io error occursInternalError
- if the SparseBitSet representation is inconsistent- Since:
- 1.6
-
readObject
Reconstitute theSparseBitSet
instance from a stream (i.e., deserialize it).- Parameters:
s
- the ObjectInputStream to use- Throws:
IOException
- if there is an io errorClassNotFoundException
- if the stream contains an unidentified class- Since:
- 1.6
-