Apache Derby Database Engine and Embedded JDBC Driver 10.17.1.0 · org.apache.derby.iapi.services.io.FormatableBitSet

Modifier and Type	Field and Description
private byte	bitsInLastByte
private transient int	lengthAsBits
private byte[]	value Bits are stored as an array of bytes.

Access	Constructor and Description
public	FormatableBitSet() Niladic Constructor
public	FormatableBitSet(int The number of bits in the set numBits) Constructs a Bit with the initial number of bits
public	FormatableBitSet(byte[] The array of bytes to make up the new Bit newValue) Constructs a Bit from an array of bytes.
public	FormatableBitSet(FormatableBitSet the FormatableBitSet to make a copy from original) Copy constructor

Method Summary

Modifier and Type	Method and Description
public void	and(FormatableBitSet bitset operand otherBit) Bitwise AND this FormatableBitSet with another FormatableBitSet.
public int	Returns: the zero-based index of the first bit that is set, or -1 if no bit is set anySetBit() If any bit is set, return the zero-based bit index of the first bit that is set.
public int	Returns: the bit number of a bit that is set, or -1 if no bit after beyondBit is set anySetBit(int Only look at bit that is greater than this bit number. Supplying a value of -1 makes the call equivalent to anySetBit(). beyondBit) Like anySetBit(), but return any set bit whose number is bigger than beyondBit.
private int	calculateLength(int realByteLength)
private final void	checkPosition(int p)
public void	clear(int the bit to clear position) Bit clear
public void	clear() Clear all the bits in this FormatableBitSet
public Object	clone() Overrides java.lang.Object.clone. Creates and returns a copy of this object.
public int	Returns: -1 - if other < this 0 - if other == this 1 - if other > this compare(FormatableBitSet the other bit to compare to other) Bit comparison.
public void	copyFrom(FormatableBitSet Bit set to copy that) Copy the bytes from another FormatableBitSet.
public boolean	Returns: TRUE\|FALSE equals(Object the other bit to compare to other) Overrides java.lang.Object.equals. Bit equivalence.
private static byte	Returns: the zero-based index of the first set bit in the argument byte firstSet(byte a non-zero byte to check for set bits v) A utility method which treats the byte argument as an 8-bit bitset and finds the first set bit in that byte.
public final boolean	Returns: true if the bit is set get(int the bit to check position) Bit get -- alias for isSet()
public byte[]	Returns: The value of the byte array getByteArray() Get the value of the byte array
public int	Returns: The length in bits for this value NOTE: could possibly be changed to a long. As is we are restricted to 2^(31-3) -> 256meg instead of 2^31 (Integer.MAX_VALUE) like other datatypes (or 2 gig). If it is ever changed to a long be sure to change read/writeExternal which write out the length in bits. getLength() Get the length in bits
public int	Returns: The length in bytes of this value getLengthInBytes() Get the length in bytes of a Bit value
public int	Returns: The number of bits that are set. getNumBitsSet() Get a count of the number of bits that are set.
public int	Returns: the formatID of this class getTypeFormatId() Implements org.apache.derby.iapi.services.io.TypedFormat.getTypeFormatId. Get the formatID which corresponds to this class.
public void	grow(int The number of bits you want. The bits are always added as 0 and are appended to the least significant end of the bit array. n) Grow (widen) a FormatableBitSet so that it contains at least N bits.
public int	Returns: the hash code hashCode() Overrides java.lang.Object.hashCode. Produce a hash code by putting the value bytes into an int, exclusive OR'ing if there are more than 4 bytes.
private void	initializeBits(int numBits)
public boolean	Returns: true if invariant holds, false otherwise invariantHolds() This method returns true if the following conditions hold: 1.
public final boolean	Returns: true if the bit is set isSet(int the bit to check position) Bit isSet
public static int	Returns: the corresponding bit count maxBitsForSpace(int Number of bits in given number of bytes numBytes) Statically calculates how many bits can fit into the number of bytes if this Bit object is externalized.
private static byte	Returns: the number of bits numBitsInLastByte(int bits bits) Figure out how many bits are in the last byte from the total number of bits.
private static int	Returns: the number of bytes numBytesFromBits(int bits bits) Figure out how many bytes are needed to store the input number of bits.
public void	or(FormatableBitSet bitset operand otherBit) Bitwise OR this FormatableBitSet with another FormatableBitSet.
public void	readExternal(ObjectInput the stream to read data from in order to restore the object in) Implements java.io.Externalizable.readExternal. Warning this method cannot be changed w/o changing SQLBit because SQLBit calls this directly w/o calling read/writeObject(), so the format id is not stored in that case.
public void	set(int the bit to set position) Bit set
public void	shrink(int The number of bits the caller wants. The bits are always removed from the least significant end of the bit array. n) Shrink (narrow) a FormatableBitSet to N bits.
public int	Returns: The length in bits for this value size() Get the length in bits -- alias for getLength()
public String	Returns: A new String containing the formatted Bit value toString() Overrides java.lang.Object.toString. Format the string into BitSet format: {0, 2, 4, 8} if bits 0, 2, 4, 8 are set.
private static int	udiv8(int i)
private static byte	umod8(int i)
private static int	umul8(int i)
public void	writeExternal(ObjectOutput the stream to write the object to out) Implements java.io.Externalizable.writeExternal. Format: int length in bits byte[]
public void	xor(FormatableBitSet bitset operand otherBit) Bitwise XOR this FormatableBitSet with another FormatableBitSet.

Inherited from java.lang.Object:: finalize getClass notify notifyAll wait wait wait

bitsInLastByte	back to summary
private byte bitsInLastByte

lengthAsBits	back to summary
private transient int lengthAsBits

value	back to summary
private byte[] value Bits are stored as an array of bytes. Bits are numbered starting at 0. Bits 0..7 go in byte[0], 8..15 in byte[1] and so on. The number of bytes is tracked as part of the byte array. The number of bits being used is derived by the number of bytes being used and the number of bits being used by the last byte. The partially unused byte is always byte[byte.length] with the lowest bits being unused. Zero length bits are stored using a zero length byte array, with all bits marked as unused.

FormatableBitSet	back to summary
public FormatableBitSet() Niladic Constructor

FormatableBitSet	back to summary
public FormatableBitSet(int numBits) Constructs a Bit with the initial number of bits Parameters numBits:int The number of bits in the set

FormatableBitSet	back to summary
public FormatableBitSet(byte[] newValue) Constructs a Bit from an array of bytes. Assume bytes are all being used. Parameters newValue:byte[] The array of bytes to make up the new Bit

FormatableBitSet	back to summary
public FormatableBitSet(FormatableBitSet original) Copy constructor Parameters original:FormatableBitSet the FormatableBitSet to make a copy from

Method Detail

and	back to summary
public void and(FormatableBitSet otherBit) Bitwise AND this FormatableBitSet with another FormatableBitSet. The result is stored in this bitset. The operand is unaffected. A null operand is treated as an empty bitset (i.e. clearing this bitset). A bitset that is smaller than its operand is expanded to the same size. Parameters otherBit:FormatableBitSet bitset operand

and

back to summary

public void and(FormatableBitSet otherBit)

Bitwise AND this FormatableBitSet with another FormatableBitSet. The result is stored in this bitset. The operand is unaffected. A null operand is treated as an empty bitset (i.e. clearing this bitset). A bitset that is smaller than its operand is expanded to the same size.

Parameters

otherBit:FormatableBitSet: bitset operand

anySetBit	back to summary
public int anySetBit() If any bit is set, return the zero-based bit index of the first bit that is set. If no bit is set, return -1. By using anySetBit() and anySetBit(beyondBit), one can quickly go thru the entire bit array to return all set bit. Returns:int the zero-based index of the first bit that is set, or -1 if no bit is set

anySetBit

back to summary

public int anySetBit()

If any bit is set, return the zero-based bit index of the first bit that is set. If no bit is set, return -1. By using anySetBit() and anySetBit(beyondBit), one can quickly go thru the entire bit array to return all set bit.

Returns:int: the zero-based index of the first bit that is set, or -1 if no bit is set

anySetBit	back to summary
public int anySetBit(int beyondBit) Like anySetBit(), but return any set bit whose number is bigger than beyondBit. If no bit is set after beyondBit, -1 is returned. By using anySetBit() and anySetBit(beyondBit), one can quickly go thru the entire bit array to return all set bit. Parameters beyondBit:int Only look at bit that is greater than this bit number. Supplying a value of -1 makes the call equivalent to anySetBit(). Returns:int the bit number of a bit that is set, or -1 if no bit after beyondBit is set

anySetBit

back to summary

public int anySetBit(int beyondBit)

Like anySetBit(), but return any set bit whose number is bigger than beyondBit. If no bit is set after beyondBit, -1 is returned. By using anySetBit() and anySetBit(beyondBit), one can quickly go thru the entire bit array to return all set bit.

Parameters

beyondBit:int: Only look at bit that is greater than this bit number. Supplying a value of -1 makes the call equivalent to anySetBit().

Returns:int

the bit number of a bit that is set, or -1 if no bit after beyondBit is set

calculateLength	back to summary
private int calculateLength(int realByteLength)

checkPosition	back to summary
private final void checkPosition(int p)

clear	back to summary
public void clear(int position) Bit clear Parameters position:int the bit to clear

clear

back to summary

public void clear(int position)

Bit clear

Parameters

position:int: the bit to clear

clear	back to summary
public void clear() Clear all the bits in this FormatableBitSet

clone back to summary

clone	back to summary
public Object clone() Overrides java.lang.Object.clone. Doc from java.lang.Object.clone. Creates and returns a copy of this object. The precise meaning of "copy" may depend on the class of the object. The general intent is that, for any object `x`, the expression: x.clone() != x will be true, and that the expression: x.clone().getClass() == x.getClass() will be `true`, but these are not absolute requirements. While it is typically the case that: x.clone().equals(x) will be `true`, this is not an absolute requirement. By convention, the returned object should be obtained by calling `super.clone`. If a class and all of its superclasses (except `Object`) obey this convention, it will be the case that `x.clone().getClass() == x.getClass()`. By convention, the object returned by this method should be independent of this object (which is being cloned). To achieve this independence, it may be necessary to modify one or more fields of the object returned by `super.clone` before returning it. Typically, this means copying any mutable objects that comprise the internal "deep structure" of the object being cloned and replacing the references to these objects with references to the copies. If a class contains only primitive fields or references to immutable objects, then it is usually the case that no fields in the object returned by `super.clone` need to be modified. Returns:Object a clone of this instance.

public Object clone()

Overrides java.lang.Object.clone.

Doc from java.lang.Object.clone.

Creates and returns a copy of this object. The precise meaning of "copy" may depend on the class of the object. The general intent is that, for any object x, the expression:

x.clone() != x

will be true, and that the expression:

x.clone().getClass() == x.getClass()

will be true, but these are not absolute requirements. While it is typically the case that:

x.clone().equals(x)

will be true, this is not an absolute requirement.

By convention, the returned object should be obtained by calling super.clone. If a class and all of its superclasses (except Object) obey this convention, it will be the case that x.clone().getClass() == x.getClass().

By convention, the object returned by this method should be independent of this object (which is being cloned). To achieve this independence, it may be necessary to modify one or more fields of the object returned by super.clone before returning it. Typically, this means copying any mutable objects that comprise the internal "deep structure" of the object being cloned and replacing the references to these objects with references to the copies. If a class contains only primitive fields or references to immutable objects, then it is usually the case that no fields in the object returned by super.clone need to be modified.

Returns:Object: a clone of this instance.

compare	back to summary
public int compare(FormatableBitSet other) Bit comparison. Compare this with other. Will always do a byte by byte compare. Given 2 similar bits of unequal lengths (x and y), where x.getLength() < y.getLength() but where: x[0..x.getLength()] == y[0..x.getLength()] then x < y. Parameters other:FormatableBitSet the other bit to compare to Returns:int -1 - if other < this 0 - if other == this 1 - if other > this

compare

back to summary

public int compare(FormatableBitSet other)

Bit comparison. Compare this with other. Will always do a byte by byte compare. Given 2 similar bits of unequal lengths (x and y), where x.getLength() < y.getLength() but where: x[0..x.getLength()] == y[0..x.getLength()] then x < y.

Parameters

other:FormatableBitSet: the other bit to compare to

Returns:int

-1 - if other < this 0 - if other == this 1 - if other > this

copyFrom	back to summary
public void copyFrom(FormatableBitSet that) Copy the bytes from another FormatableBitSet. Assumes that this bit set is at least as large as the argument's bit set. Parameters that:FormatableBitSet Bit set to copy

copyFrom

back to summary

public void copyFrom(FormatableBitSet that)

Copy the bytes from another FormatableBitSet. Assumes that this bit set is at least as large as the argument's bit set.

Parameters

that:FormatableBitSet: Bit set to copy

equals	back to summary
public boolean equals(Object other) Overrides java.lang.Object.equals. Bit equivalence. Compare this with other. If the length is different, then cannot be equal so short circuit. Otherwise, rely on compare(). Note that two zero length bits are considered equal. Parameters other:Object the other bit to compare to Returns:boolean TRUE\|FALSE

equals

back to summary

public boolean equals(Object other)

Overrides java.lang.Object.equals.

Bit equivalence. Compare this with other. If the length is different, then cannot be equal so short circuit. Otherwise, rely on compare(). Note that two zero length bits are considered equal.

Parameters

other:Object: the other bit to compare to

Returns:boolean

TRUE|FALSE

firstSet	back to summary
private static byte firstSet(byte v) A utility method which treats the byte argument as an 8-bit bitset and finds the first set bit in that byte. Assumes that at least one bit in v is set (v!=0). Parameters v:byte a non-zero byte to check for set bits Returns:byte the zero-based index of the first set bit in the argument byte

firstSet

back to summary

private static byte firstSet(byte v)

A utility method which treats the byte argument as an 8-bit bitset and finds the first set bit in that byte. Assumes that at least one bit in v is set (v!=0).

Parameters

v:byte: a non-zero byte to check for set bits

Returns:byte

the zero-based index of the first set bit in the argument byte

get	back to summary
public final boolean get(int position) Bit get -- alias for isSet() Parameters position:int the bit to check Returns:boolean true if the bit is set

get

back to summary

public final boolean get(int position)

Bit get -- alias for isSet()

Parameters

position:int: the bit to check

Returns:boolean

true if the bit is set

getByteArray	back to summary
public byte[] getByteArray() Get the value of the byte array Returns:byte[] The value of the byte array

getByteArray

back to summary

public byte[] getByteArray()

Get the value of the byte array

Returns:byte[]: The value of the byte array

getLength	back to summary
public int getLength() Get the length in bits Returns:int The length in bits for this value NOTE: could possibly be changed to a long. As is we are restricted to 2^(31-3) -> 256meg instead of 2^31 (Integer.MAX_VALUE) like other datatypes (or 2 gig). If it is ever changed to a long be sure to change read/writeExternal which write out the length in bits.

getLength

back to summary

public int getLength()

Get the length in bits

Returns:int: The length in bits for this value NOTE: could possibly be changed to a long. As is we are restricted to 2^(31-3) -> 256meg instead of 2^31 (Integer.MAX_VALUE) like other datatypes (or 2 gig). If it is ever changed to a long be sure to change read/writeExternal which write out the length in bits.

getLengthInBytes	back to summary
public int getLengthInBytes() Get the length in bytes of a Bit value Returns:int The length in bytes of this value

getLengthInBytes

back to summary

public int getLengthInBytes()

Get the length in bytes of a Bit value

Returns:int: The length in bytes of this value

getNumBitsSet	back to summary
public int getNumBitsSet() Get a count of the number of bits that are set. Returns:int The number of bits that are set.

getNumBitsSet

back to summary

public int getNumBitsSet()

Get a count of the number of bits that are set.

Returns:int: The number of bits that are set.

getTypeFormatId	back to summary
public int getTypeFormatId() Implements org.apache.derby.iapi.services.io.TypedFormat.getTypeFormatId. Get the formatID which corresponds to this class. Returns:int the formatID of this class

getTypeFormatId

back to summary

public int getTypeFormatId()

Implements org.apache.derby.iapi.services.io.TypedFormat.getTypeFormatId.

Get the formatID which corresponds to this class.

Returns:int: the formatID of this class

grow	back to summary
public void grow(int n) Grow (widen) a FormatableBitSet so that it contains at least N bits. If the bitset already has more than n bits, this is a noop. Negative values of n are not allowed. ASSUMPTIONS: that all extra bits in the last byte are zero. Parameters n:int The number of bits you want. The bits are always added as 0 and are appended to the least significant end of the bit array.

grow

back to summary

public void grow(int n)

Grow (widen) a FormatableBitSet so that it contains at least N bits. If the bitset already has more than n bits, this is a noop. Negative values of n are not allowed. ASSUMPTIONS: that all extra bits in the last byte are zero.

Parameters

n:int: The number of bits you want. The bits are always added as 0 and are appended to the least significant end of the bit array.

hashCode	back to summary
public int hashCode() Overrides java.lang.Object.hashCode. Produce a hash code by putting the value bytes into an int, exclusive OR'ing if there are more than 4 bytes. Returns:int the hash code

hashCode

back to summary

public int hashCode()

Overrides java.lang.Object.hashCode.

Produce a hash code by putting the value bytes into an int, exclusive OR'ing if there are more than 4 bytes.

Returns:int: the hash code

initializeBits	back to summary
private void initializeBits(int numBits)

invariantHolds	back to summary
public boolean invariantHolds() This method returns true if the following conditions hold: 1. The number of bits in the bitset will fit into the allocated byte array. 2. 'lengthAsBits' and 'bitsInLastByte' are consistent. 3. All unused bits in the byte array are unset. This represents an invariant for the class, so this method should always return true. The method is public, but is primarily intended for testing and ASSERTS. Returns:boolean true if invariant holds, false otherwise

invariantHolds

back to summary

public boolean invariantHolds()

This method returns true if the following conditions hold: 1. The number of bits in the bitset will fit into the allocated byte array. 2. 'lengthAsBits' and 'bitsInLastByte' are consistent. 3. All unused bits in the byte array are unset. This represents an invariant for the class, so this method should always return true. The method is public, but is primarily intended for testing and ASSERTS.

Returns:boolean: true if invariant holds, false otherwise

isSet	back to summary
public final boolean isSet(int position) Bit isSet Parameters position:int the bit to check Returns:boolean true if the bit is set

isSet

back to summary

public final boolean isSet(int position)

Bit isSet

Parameters

position:int: the bit to check

Returns:boolean

true if the bit is set

maxBitsForSpace	back to summary
public static int maxBitsForSpace(int numBytes) Statically calculates how many bits can fit into the number of bytes if this Bit object is externalized. Only valid for this implementation of Bit. Parameters numBytes:int Number of bits in given number of bytes Returns:int the corresponding bit count

maxBitsForSpace

back to summary

public static int maxBitsForSpace(int numBytes)

Statically calculates how many bits can fit into the number of bytes if this Bit object is externalized. Only valid for this implementation of Bit.

Parameters

numBytes:int: Number of bits in given number of bytes

Returns:int

the corresponding bit count

numBitsInLastByte	back to summary
private static byte numBitsInLastByte(int bits) Figure out how many bits are in the last byte from the total number of bits. Parameters bits:int bits Returns:byte the number of bits

numBitsInLastByte

back to summary

private static byte numBitsInLastByte(int bits)

Figure out how many bits are in the last byte from the total number of bits.

Parameters

bits:int: bits

Returns:byte

the number of bits

numBytesFromBits	back to summary
private static int numBytesFromBits(int bits) Figure out how many bytes are needed to store the input number of bits. Parameters bits:int bits Returns:int the number of bytes

numBytesFromBits

back to summary

private static int numBytesFromBits(int bits)

Figure out how many bytes are needed to store the input number of bits.

Parameters

bits:int: bits

Returns:int

the number of bytes

or	back to summary
public void or(FormatableBitSet otherBit) Bitwise OR this FormatableBitSet with another FormatableBitSet. The result is stored in this bitset. The operand is unaffected. A null operand is treated as an empty bitset (i.e. a noop). A bitset that is smaller than its operand is expanded to the same size. Parameters otherBit:FormatableBitSet bitset operand

back to summary

public void or(FormatableBitSet otherBit)

Bitwise OR this FormatableBitSet with another FormatableBitSet. The result is stored in this bitset. The operand is unaffected. A null operand is treated as an empty bitset (i.e. a noop). A bitset that is smaller than its operand is expanded to the same size.

Parameters

otherBit:FormatableBitSet: bitset operand

readExternal back to summary

readExternal	back to summary
public void readExternal(ObjectInput in) throws IOException Implements java.io.Externalizable.readExternal. Note gracefully handles zero length bits -- will create a zero length array with no bits being used. Fortunately in.read() is ok with a zero length array so no special code. Warning this method cannot be changed w/o changing SQLBit because SQLBit calls this directly w/o calling read/writeObject(), so the format id is not stored in that case. Parameters in:ObjectInput Doc from java.io.Externalizable.readExternal. the stream to read data from in order to restore the object Exceptions IOException: Doc from java.io.Externalizable.readExternal. if I/O errors occur See Also `java.io.Externalizable#readExternal`

public void readExternal(ObjectInput in) throws IOException

Implements java.io.Externalizable.readExternal.

Note

gracefully handles zero length bits -- will create a zero length array with no bits being used. Fortunately in.read() is ok with a zero length array so no special code.

Warning

this method cannot be changed w/o changing SQLBit because SQLBit calls this directly w/o calling read/writeObject(), so the format id is not stored in that case.

Parameters

in:ObjectInput

Doc from java.io.Externalizable.readExternal.

the stream to read data from in order to restore the object

Exceptions

IOException:

Doc from java.io.Externalizable.readExternal.

if I/O errors occur

See Also

java.io.Externalizable#readExternal

set	back to summary
public void set(int position) Bit set Parameters position:int the bit to set

set

back to summary

public void set(int position)

Bit set

Parameters

position:int: the bit to set

shrink	back to summary
public void shrink(int n) Shrink (narrow) a FormatableBitSet to N bits. N may not be larger than the current bitset size, or negative. Parameters n:int The number of bits the caller wants. The bits are always removed from the least significant end of the bit array.

shrink

back to summary

public void shrink(int n)

Shrink (narrow) a FormatableBitSet to N bits. N may not be larger than the current bitset size, or negative.

Parameters

n:int: The number of bits the caller wants. The bits are always removed from the least significant end of the bit array.

size	back to summary
public int size() Get the length in bits -- alias for getLength() Returns:int The length in bits for this value

size

back to summary

public int size()

Get the length in bits -- alias for getLength()

Returns:int: The length in bits for this value

toString	back to summary
public String toString() Overrides java.lang.Object.toString. Format the string into BitSet format: {0, 2, 4, 8} if bits 0, 2, 4, 8 are set. Returns:String A new String containing the formatted Bit value

toString

back to summary

public String toString()

Overrides java.lang.Object.toString.

Format the string into BitSet format: {0, 2, 4, 8} if bits 0, 2, 4, 8 are set.

Returns:String: A new String containing the formatted Bit value

udiv8	back to summary
private static int udiv8(int i)

umod8	back to summary
private static byte umod8(int i)

umul8	back to summary
private static int umul8(int i)

writeExternal back to summary

writeExternal	back to summary
public void writeExternal(ObjectOutput out) throws IOException Implements java.io.Externalizable.writeExternal. Format: int length in bits byte[] Parameters out:ObjectOutput Doc from java.io.Externalizable.writeExternal. the stream to write the object to Exceptions IOException: Doc from java.io.Externalizable.writeExternal. Includes any I/O exceptions that may occur See Also `java.io.Externalizable#writeExternal`

public void writeExternal(ObjectOutput out) throws IOException

Implements java.io.Externalizable.writeExternal.

Format:

int length in bits
byte[]

Parameters

out:ObjectOutput

Doc from java.io.Externalizable.writeExternal.

the stream to write the object to

Exceptions

IOException:

Doc from java.io.Externalizable.writeExternal.

Includes any I/O exceptions that may occur

See Also

java.io.Externalizable#writeExternal

xor	back to summary
public void xor(FormatableBitSet otherBit) Bitwise XOR this FormatableBitSet with another FormatableBitSet. The result is stored in this bitset. The operand is unaffected. A null operand is treated as an empty bitset (i.e. a noop). A bitset that is smaller than its operand is expanded to the same size. Parameters otherBit:FormatableBitSet bitset operand

xor

back to summary

public void xor(FormatableBitSet otherBit)

Bitwise XOR this FormatableBitSet with another FormatableBitSet. The result is stored in this bitset. The operand is unaffected. A null operand is treated as an empty bitset (i.e. a noop). A bitset that is smaller than its operand is expanded to the same size.

Parameters

otherBit:FormatableBitSet: bitset operand

public final Class FormatableBitSet

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail