org.apache.cassandra.db.marshal

Interface ValueAccessor<V>

Type Parameters:

V - the backing type

All Known Implementing Classes:

ByteArrayAccessor, ByteBufferAccessor

public interface ValueAccessor<V>

ValueAccessor allows serializers and other code dealing with raw bytes to operate on different backing types (ie: byte arrays, byte buffers, etc) without requiring that the supported backing types share a common type ancestor and without incuring the allocation cost of a wrapper object. A note on byte buffers for implementors: the "value" of a byte buffer is always interpreted as beginning at it's Buffer.position() and having a length of Buffer.remaining(). ValueAccessor implementations need to maintain this internally. ValueAccessors should also never modify the state of the byte buffers view (ie: offset, limit). This would also apply to value accessors for simlilar types (ie: netty's ByteBuf}.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static interface	ValueAccessor.ObjectFactory<V> Creates db objects using the given accessors value type.

Method Summary

Modifier and Type	Method and Description
V	allocate(int size) Allocate and return a instance of bytes on the heap.
static <L,R> int	compare(L left, ValueAccessor<L> leftAccessor, R right, ValueAccessor<R> rightAccessor) lexicographically compare to
<VR> int	compare(V left, VR right, ValueAccessor<VR> accessorR) lexicographically compare to
int	compareByteArrayTo(byte[] left, V right) compare a byte array on the left with a on the right}
int	compareByteBufferTo(java.nio.ByteBuffer left, V right) compare a byte buffer on the left with a on the right}
<V2> V	convert(V2 src, ValueAccessor<V2> accessor) Convert the data in to and the returned value may share a common byte array instance, so caller should assume that modifying the returned value will also modify the contents of
int	copyByteArrayTo(byte[] src, int srcOffset, V dst, int dstOffset, int size) copies a byte array into this accessors value.
int	copyByteBufferTo(java.nio.ByteBuffer src, int srcOffset, V dst, int dstOffset, int size) copies a byte buffer into this accessors value.
<V2> int	copyTo(V src, int srcOffset, V2 dst, ValueAccessor<V2> dstAccessor, int dstOffset, int size) copy the bytes from the value, starting at the offset into the value, starting at the offset , using the accessor
V[]	createArray(int length) allocate an instance of the accessors backing type
default void	digest(V value, Digest digest) updates with te contents of
void	digest(V value, int offset, int size, Digest digest) updates with bytes from the contents of starting at offset
V	empty() return a value with a length of 0
static <L,R> boolean	equals(L left, ValueAccessor<L> leftAccessor, R right, ValueAccessor<R> rightAccessor)
ValueAccessor.ObjectFactory<V>	factory() returns the ValueAccessor.ObjectFactory for the backing type
default boolean	getBoolean(V value, int offset) returns a boolean from offset
byte	getByte(V value, int offset) returns a byte from offset
int	getInt(V value, int offset) returns an int from offset
long	getLong(V value, int offset) returns a long from offset
short	getShort(V value, int offset) returns a short from offset
int	getUnsignedShort(V value, int offset) returns an unsigned short from offset
default int	hashCode(V value)
default boolean	isEmpty(V value)
default boolean	isEmptyFromOffset(V value, int offset)
int	putInt(V dst, int offset, int value) writes the int value to at offset
int	putLong(V dst, int offset, long value) writes the long value to at offset
int	putShort(V dst, int offset, short value) writes the short value to at offset
V	read(DataInputPlus in, int length) Reads a value of bytes from
int	size(V value)
default int	sizeFromOffset(V value, int offset)
default int	sizeWithShortLength(V value) serialized size including a short length prefix
default int	sizeWithVIntLength(V value) serializes size including a vint length prefix
V	slice(V input, int offset, int length) Returns a value with the contents of from to .
default V	sliceWithShortLength(V input, int offset) same as slice(Object, int, int), except the length is taken from the first 2 bytes from the given offset (and not included in the return value)
byte[]	toArray(V value) returns a byte[] with the contents of Depending on the accessor implementation, this method may: * allocate a new byte[] object and copy data into it * return the value, if the backing type is byte[]
byte[]	toArray(V value, int offset, int length) returns a byte[] with bytes copied from the contents of starting at offset .
java.nio.ByteBuffer	toBuffer(V value) returns a ByteBuffer with the contents of Depending on the accessor implementation, this method may: * allocate a new ByteBuffer and copy data into it * return the value, if the backing type is a bytebuffer
byte	toByte(V value) returns a byte from offset 0
double	toDouble(V value) returns a double from offset 0
float	toFloat(V value) returns a float from offset 0
java.lang.String	toHex(V value)
int	toInt(V value) returns an int from offset 0
long	toLong(V value) returns a long from offset 0
short	toShort(V value) returns a short from offset 0
default java.lang.String	toString(V value)
java.lang.String	toString(V value, java.nio.charset.Charset charset)
java.util.UUID	toUUID(V value) returns a UUID from offset 0
V	valueOf(boolean v) return a value with the bytes from
V	valueOf(byte v) return a value with the bytes from
V	valueOf(byte[] bytes) return a value containing the Caller should assume that modifying the returned value will also modify the contents of
V	valueOf(java.nio.ByteBuffer bytes) return a value containing the and the returned value may share a common byte array instance, so caller should assume that modifying the returned value will also modify the contents of
V	valueOf(double v) return a value with the bytes from
V	valueOf(float v) return a value with the bytes from
V	valueOf(int v) return a value with the bytes from
V	valueOf(long v) return a value with the bytes from
V	valueOf(short v) return a value with the bytes from
V	valueOf(java.lang.String s, java.nio.charset.Charset charset) return a value containing the bytes for the given string and charset
V	valueOf(java.util.UUID v) return a value with the bytes from
void	write(V value, java.nio.ByteBuffer out) Write the contents of the given value into the ByteBuffer
void	write(V value, DataOutputPlus out) Write the contents of the given value into the a DataOutputPlus
default void	writeWithVIntLength(V value, DataOutputPlus out)

Method Detail

size

int size(V value)

Returns:

the size of the given value

sizeWithVIntLength

default int sizeWithVIntLength(V value)

serializes size including a vint length prefix

sizeWithShortLength

default int sizeWithShortLength(V value)

serialized size including a short length prefix

isEmpty

default boolean isEmpty(V value)

Returns:

true if the size of the given value is zero, false otherwise

sizeFromOffset

default int sizeFromOffset(V value,
                           int offset)

Returns:

the number of bytes remaining in the value from the given offset

isEmptyFromOffset

default boolean isEmptyFromOffset(V value,
                                  int offset)

Returns:

true if there are no bytes present after the given offset, false otherwise

createArray

V[] createArray(int length)

allocate an instance of the accessors backing type

Parameters:

length - size of backing typ to allocate

write

void write(V value,
           DataOutputPlus out)
    throws java.io.IOException

Write the contents of the given value into the a DataOutputPlus

Throws:

java.io.IOException

writeWithVIntLength

default void writeWithVIntLength(V value,
                                 DataOutputPlus out)
                          throws java.io.IOException

Throws:

java.io.IOException

write

void write(V value,
           java.nio.ByteBuffer out)

Write the contents of the given value into the ByteBuffer

copyTo

<V2> int copyTo(V src,
                int srcOffset,
                V2 dst,
                ValueAccessor<V2> dstAccessor,
                int dstOffset,
                int size)

copy the bytes from the value, starting at the offset into the value, starting at the offset , using the accessor

Type Parameters:

V2 - the destination value type

Returns:

the number of bytes copied ()

copyByteArrayTo

int copyByteArrayTo(byte[] src,
                    int srcOffset,
                    V dst,
                    int dstOffset,
                    int size)

copies a byte array into this accessors value.

copyByteBufferTo

int copyByteBufferTo(java.nio.ByteBuffer src,
                     int srcOffset,
                     V dst,
                     int dstOffset,
                     int size)

copies a byte buffer into this accessors value.

digest

void digest(V value,
            int offset,
            int size,
            Digest digest)

updates with bytes from the contents of starting at offset

digest

default void digest(V value,
                    Digest digest)

updates with te contents of

read

V read(DataInputPlus in,
       int length)
throws java.io.IOException

Reads a value of bytes from

Throws:

java.io.IOException

slice

V slice(V input,
        int offset,
        int length)

Returns a value with the contents of from to . Depending on the accessor implementation, this method may: * allocate a new object of , and copy data into it * return a view of where changes to one will be reflected in the other

sliceWithShortLength

default V sliceWithShortLength(V input,
                               int offset)

same as slice(Object, int, int), except the length is taken from the first 2 bytes from the given offset (and not included in the return value)

compare

<VR> int compare(V left,
                 VR right,
                 ValueAccessor<VR> accessorR)

lexicographically compare to

Type Parameters:

VR - backing type of

compareByteArrayTo

int compareByteArrayTo(byte[] left,
                       V right)

compare a byte array on the left with a on the right}

compareByteBufferTo

int compareByteBufferTo(java.nio.ByteBuffer left,
                        V right)

compare a byte buffer on the left with a on the right}

hashCode

default int hashCode(V value)

toBuffer

java.nio.ByteBuffer toBuffer(V value)

returns a ByteBuffer with the contents of Depending on the accessor implementation, this method may: * allocate a new ByteBuffer and copy data into it * return the value, if the backing type is a bytebuffer

toArray

byte[] toArray(V value)

returns a byte[] with the contents of Depending on the accessor implementation, this method may: * allocate a new byte[] object and copy data into it * return the value, if the backing type is byte[]

toArray

byte[] toArray(V value,
               int offset,
               int length)

returns a byte[] with bytes copied from the contents of starting at offset . Depending on the accessor implementation, this method may: * allocate a new byte[] object and copy data into it * return the value, if the backing type is byte[], offset is 0 and == size(value)

toString

java.lang.String toString(V value,
                          java.nio.charset.Charset charset)
                   throws java.nio.charset.CharacterCodingException

Throws:

java.nio.charset.CharacterCodingException

toString

default java.lang.String toString(V value)
                           throws java.nio.charset.CharacterCodingException

Throws:

java.nio.charset.CharacterCodingException

toHex

java.lang.String toHex(V value)

getBoolean

default boolean getBoolean(V value,
                           int offset)

returns a boolean from offset

toByte

byte toByte(V value)

returns a byte from offset 0

getByte

byte getByte(V value,
             int offset)

returns a byte from offset

toShort

short toShort(V value)

returns a short from offset 0

getShort

short getShort(V value,
               int offset)

returns a short from offset

getUnsignedShort

int getUnsignedShort(V value,
                     int offset)

returns an unsigned short from offset

toInt

int toInt(V value)

returns an int from offset 0

getInt

int getInt(V value,
           int offset)

returns an int from offset

toLong

long toLong(V value)

returns a long from offset 0

getLong

long getLong(V value,
             int offset)

returns a long from offset

toFloat

float toFloat(V value)

returns a float from offset 0

toDouble

double toDouble(V value)

returns a double from offset 0

toUUID

java.util.UUID toUUID(V value)

returns a UUID from offset 0

putShort

int putShort(V dst,
             int offset,
             short value)

writes the short value to at offset

Returns:

the number of bytes written to

putInt

int putInt(V dst,
           int offset,
           int value)

writes the int value to at offset

Returns:

the number of bytes written to

putLong

int putLong(V dst,
            int offset,
            long value)

writes the long value to at offset

Returns:

the number of bytes written to

empty

V empty()

return a value with a length of 0

valueOf

V valueOf(byte[] bytes)

return a value containing the Caller should assume that modifying the returned value will also modify the contents of

valueOf

V valueOf(java.nio.ByteBuffer bytes)

return a value containing the and the returned value may share a common byte array instance, so caller should assume that modifying the returned value will also modify the contents of

valueOf

V valueOf(java.lang.String s,
          java.nio.charset.Charset charset)

return a value containing the bytes for the given string and charset

valueOf

V valueOf(java.util.UUID v)

return a value with the bytes from

valueOf

V valueOf(boolean v)

return a value with the bytes from

valueOf

V valueOf(byte v)

return a value with the bytes from

valueOf

V valueOf(short v)

return a value with the bytes from

valueOf

V valueOf(int v)

return a value with the bytes from

valueOf

V valueOf(long v)

return a value with the bytes from

valueOf

V valueOf(float v)

return a value with the bytes from

valueOf

V valueOf(double v)

return a value with the bytes from

convert

<V2> V convert(V2 src,
               ValueAccessor<V2> accessor)

Convert the data in to and the returned value may share a common byte array instance, so caller should assume that modifying the returned value will also modify the contents of

allocate

V allocate(int size)

Allocate and return a instance of bytes on the heap.

factory

ValueAccessor.ObjectFactory<V> factory()

returns the ValueAccessor.ObjectFactory for the backing type

compare

static <L,R> int compare(L left,
                         ValueAccessor<L> leftAccessor,
                         R right,
                         ValueAccessor<R> rightAccessor)

lexicographically compare to

equals

static <L,R> boolean equals(L left,
                            ValueAccessor<L> leftAccessor,
                            R right,
                            ValueAccessor<R> rightAccessor)