org.apache.arrow.vector

Class ZeroVector

java.lang.Object

org.apache.arrow.vector.ZeroVector

All Implemented Interfaces:

Closeable, AutoCloseable, Iterable<ValueVector>, FieldVector, ValueVector

public class ZeroVector
extends Object
implements FieldVector

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.arrow.vector.ValueVector

ValueVector.Accessor, ValueVector.Mutator

Field Summary

Fields

Modifier and Type	Field and Description
static ZeroVector	INSTANCE

Constructor Summary

Constructors

Constructor and Description
ZeroVector()

Method Summary

Methods

Modifier and Type	Method and Description
void	allocateNew() Allocate new buffers.
boolean	allocateNewSafe() Allocates new buffers.
void	clear() Release the underlying ArrowBuf and reset the ValueVector to empty.
void	close() Alternative to clear().
ValueVector.Accessor	getAccessor() Returns an accessor that is used to read from this vector instance.
BufferAllocator	getAllocator()
ArrowBuf[]	getBuffers(boolean clear) Return the underlying buffers associated with this vector.
int	getBufferSize() Returns the number of bytes that is used by this vector instance.
int	getBufferSizeFor(int valueCount) Returns the number of bytes that is used by this vector if it holds the given number of values.
List<FieldVector>	getChildrenFromFields() the returned list is the same size as the list passed to initializeChildrenFromFields
Field	getField() Get information about how this field is materialized.
List<ArrowBuf>	getFieldBuffers() (same size as getFieldVectors() since it is their content)
List<BufferBacked>	getFieldInnerVectors()
Types.MinorType	getMinorType()
ValueVector.Mutator	getMutator() Returns an mutator that is used to write to this vector instance.
FieldReader	getReader() Returns a field reader that supports reading values from this vector.
TransferPair	getTransferPair(BufferAllocator allocator) Returns a transfer pair, creating a new target vector of the same type.
TransferPair	getTransferPair(String ref, BufferAllocator allocator)
int	getValueCapacity() Returns the maximum number of values that can be stored in this vector instance.
void	initializeChildrenFromFields(List<Field> children) Initializes the child vectors to be later loaded with loadBuffers
Iterator<ValueVector>	iterator()
void	loadFieldBuffers(ArrowFieldNode fieldNode, List<ArrowBuf> ownBuffers) loads data in the vectors (ownBuffers must be the same size as getFieldVectors())
TransferPair	makeTransferPair(ValueVector target) Returns a new transfer pair that is used to transfer underlying buffers into the target vector.
void	setInitialCapacity(int numRecords) Set the initial record capacity

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

INSTANCE

public static final ZeroVector INSTANCE

Constructor Detail

ZeroVector

public ZeroVector()

Method Detail

close

public void close()

Description copied from interface: ValueVector

Alternative to clear(). Allows use as an AutoCloseable in try-with-resources.

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Specified by:

close in interface ValueVector

clear

public void clear()

Description copied from interface: ValueVector

Release the underlying ArrowBuf and reset the ValueVector to empty.

Specified by:

clear in interface ValueVector

getField

public Field getField()

Description copied from interface: ValueVector

Get information about how this field is materialized.

Specified by:

getField in interface ValueVector

getMinorType

public Types.MinorType getMinorType()

Specified by:

getMinorType in interface ValueVector

getTransferPair

public TransferPair getTransferPair(BufferAllocator allocator)

Description copied from interface: ValueVector

Returns a transfer pair, creating a new target vector of the same type.

Specified by:

getTransferPair in interface ValueVector

iterator

public Iterator<ValueVector> iterator()

Specified by:

iterator in interface Iterable<ValueVector>

getBufferSize

public int getBufferSize()

Description copied from interface: ValueVector

Returns the number of bytes that is used by this vector instance.

Specified by:

getBufferSize in interface ValueVector

getBufferSizeFor

public int getBufferSizeFor(int valueCount)

Description copied from interface: ValueVector

Returns the number of bytes that is used by this vector if it holds the given number of values. The result will be the same as if Mutator.setValueCount() were called, followed by calling getBufferSize(), but without any of the closing side-effects that setValueCount() implies wrt finishing off the population of a vector. Some operations might wish to use this to determine how much memory has been used by a vector so far, even though it is not finished being populated.

Specified by:

getBufferSizeFor in interface ValueVector

Parameters:

valueCount - the number of values to assume this vector contains

Returns:

the buffer size if this vector is holding valueCount values

getBuffers

public ArrowBuf[] getBuffers(boolean clear)

Description copied from interface: ValueVector

Return the underlying buffers associated with this vector. Note that this doesn't impact the reference counts for this buffer so it only should be used for in-context access. Also note that this buffer changes regularly thus external classes shouldn't hold a reference to it (unless they change it).

Specified by:

getBuffers in interface ValueVector

Parameters:

clear - Whether to clear vector before returning; the buffers will still be refcounted; but the returned array will be the only reference to them

Returns:

The underlying buffers that is used by this vector instance.

allocateNew

public void allocateNew()
                 throws OutOfMemoryException

Description copied from interface: ValueVector

Allocate new buffers. ValueVector implements logic to determine how much to allocate.

Specified by:

allocateNew in interface ValueVector

Throws:

OutOfMemoryException - Thrown if no memory can be allocated.

allocateNewSafe

public boolean allocateNewSafe()

Description copied from interface: ValueVector

Allocates new buffers. ValueVector implements logic to determine how much to allocate.

Specified by:

allocateNewSafe in interface ValueVector

Returns:

Returns true if allocation was successful.

getAllocator

public BufferAllocator getAllocator()

Specified by:

getAllocator in interface ValueVector

setInitialCapacity

public void setInitialCapacity(int numRecords)

Description copied from interface: ValueVector

Set the initial record capacity

Specified by:

setInitialCapacity in interface ValueVector

Parameters:

numRecords - the initial record capacity.

getValueCapacity

public int getValueCapacity()

Description copied from interface: ValueVector

Returns the maximum number of values that can be stored in this vector instance.

Specified by:

getValueCapacity in interface ValueVector

getTransferPair

public TransferPair getTransferPair(String ref,
                           BufferAllocator allocator)

Specified by:

getTransferPair in interface ValueVector

makeTransferPair

public TransferPair makeTransferPair(ValueVector target)

Description copied from interface: ValueVector

Returns a new transfer pair that is used to transfer underlying buffers into the target vector.

Specified by:

makeTransferPair in interface ValueVector

getAccessor

public ValueVector.Accessor getAccessor()

Description copied from interface: ValueVector

Returns an accessor that is used to read from this vector instance.

Specified by:

getAccessor in interface ValueVector

getMutator

public ValueVector.Mutator getMutator()

Description copied from interface: ValueVector

Returns an mutator that is used to write to this vector instance.

Specified by:

getMutator in interface ValueVector

getReader

public FieldReader getReader()

Description copied from interface: ValueVector

Returns a field reader that supports reading values from this vector.

Specified by:

getReader in interface ValueVector

initializeChildrenFromFields

public void initializeChildrenFromFields(List<Field> children)

Description copied from interface: FieldVector

Initializes the child vectors to be later loaded with loadBuffers

Specified by:

initializeChildrenFromFields in interface FieldVector

Parameters:

children - the schema

getChildrenFromFields

public List<FieldVector> getChildrenFromFields()

Description copied from interface: FieldVector

the returned list is the same size as the list passed to initializeChildrenFromFields

Specified by:

getChildrenFromFields in interface FieldVector

Returns:

the children according to schema (empty for primitive types)

loadFieldBuffers

public void loadFieldBuffers(ArrowFieldNode fieldNode,
                    List<ArrowBuf> ownBuffers)

Description copied from interface: FieldVector

loads data in the vectors (ownBuffers must be the same size as getFieldVectors())

Specified by:

loadFieldBuffers in interface FieldVector

Parameters:

fieldNode - the fieldNode

ownBuffers - the buffers for this Field (own buffers only, children not included)

getFieldBuffers

public List<ArrowBuf> getFieldBuffers()

Description copied from interface: FieldVector

(same size as getFieldVectors() since it is their content)

Specified by:

getFieldBuffers in interface FieldVector

Returns:

the buffers containing the data for this vector (ready for reading)

getFieldInnerVectors

public List<BufferBacked> getFieldInnerVectors()

Specified by:

getFieldInnerVectors in interface FieldVector

Returns:

the inner vectors for this field as defined by the TypeLayout