org.apache.arrow.vector.complex

Class ListVector

java.lang.Object

org.apache.arrow.vector.BaseValueVector

org.apache.arrow.vector.complex.BaseRepeatedValueVector

org.apache.arrow.vector.complex.ListVector

All Implemented Interfaces:

Closeable, AutoCloseable, Iterable<ValueVector>, BaseListVector, PromotableVector, RepeatedValueVector, DensityAwareVector, FieldVector, ValueVector

Direct Known Subclasses:

MapVector

public class ListVector
extends BaseRepeatedValueVector
implements PromotableVector

A list vector contains lists of a specific type of elements. Its structure contains 3 elements.

1. A validity buffer.
2. An offset buffer, that denotes lists boundaries.
3. A child data vector that contains the elements of lists.

The latter two are managed by its superclass.

Field Summary

Fields

Modifier and Type	Field and Description
protected Field	field
protected int	lastSet The maximum index that is actually set.
protected UnionListReader	reader
protected int	validityAllocationSizeInBytes
protected ArrowBuf	validityBuffer

Fields inherited from class org.apache.arrow.vector.complex.BaseRepeatedValueVector

DATA_VECTOR_NAME, DEFAULT_DATA_VECTOR, defaultDataVectorName, OFFSET_WIDTH, offsetAllocationSizeInBytes, offsetBuffer, valueCount, vector

Fields inherited from class org.apache.arrow.vector.BaseValueVector

allocator, fieldReader, INITIAL_VALUE_ALLOCATION, MAX_ALLOCATION_SIZE, MAX_ALLOCATION_SIZE_PROPERTY

Fields inherited from interface org.apache.arrow.vector.complex.RepeatedValueVector

DEFAULT_REPEAT_PER_RECORD

Constructor Summary

Constructors

Constructor and Description
ListVector(Field field, BufferAllocator allocator, CallBack callBack) Constructs a new instance.
ListVector(String name, BufferAllocator allocator, FieldType fieldType, CallBack callBack) Constructs a new instance.

Method Summary

Modifier and Type	Method and Description
<OUT,IN> OUT	accept(VectorVisitor<OUT,IN> visitor, IN value) Accept a generic VectorVisitor and return the result.
<T extends ValueVector> AddOrGetResult<T>	addOrGetVector(FieldType fieldType) Initialize the child data vector to field type.
void	allocateNew() Same as allocateNewSafe().
boolean	allocateNewSafe() Allocate memory for the vector.
protected void	allocateValidityBuffer(long size)
void	clear() Release any owned ArrowBuf and reset the ValueVector to the initial state.
void	copyFrom(int inIndex, int outIndex, ValueVector from) Copy a cell value from a particular index in source vector to a particular position in this vector.
void	copyFromSafe(int inIndex, int outIndex, ValueVector from) Same as copyFrom(int, int, ValueVector) except that it handles the case when the capacity of the vector needs to be expanded before copy.
static ListVector	empty(String name, BufferAllocator allocator)
void	endValue(int index, int size) End the current value.
ArrowBuf[]	getBuffers(boolean clear) Return the underlying buffers associated with this vector.
int	getBufferSize() Get the size (number of bytes) of underlying buffers used by this vector.
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.
ArrowBuf	getDataBuffer() Gets the underlying buffer associated with data vector.
long	getDataBufferAddress() Gets the starting address of the underlying buffer associated with data vector.
FieldVector	getDataVector() Get the inner data vector for this list vector.
double	getDensity() Get the density of this ListVector.
int	getElementEndIndex(int index) Get data vector end index with the given list index.
int	getElementStartIndex(int index) Get data vector start index with the given list index.
Field	getField() Get information about how this field is materialized.
List<ArrowBuf>	getFieldBuffers() Get the buffers belonging to this vector.
List<BufferBacked>	getFieldInnerVectors() Deprecated. This API will be removed as the current implementations no longer support inner vectors.
int	getLastSet()
Types.MinorType	getMinorType()
int	getNullCount() Get the number of elements that are null in the vector.
List<?>	getObject(int index) Get the element in the list vector at a particular index.
ArrowBuf	getOffsetBuffer() Gets the underlying buffer associated with offset vector.
long	getOffsetBufferAddress() Gets the starting address of the underlying buffer associated with offset vector.
UnionListReader	getReader() Default implementation to create a reader for the vector.
protected FieldReader	getReaderImpl() Each vector has a different reader that implements the FieldReader interface.
TransferPair	getTransferPair(Field field, BufferAllocator allocator) To transfer quota responsibility.
TransferPair	getTransferPair(Field field, BufferAllocator allocator, CallBack callBack) To transfer quota responsibility.
TransferPair	getTransferPair(String ref, BufferAllocator allocator) To transfer quota responsibility.
TransferPair	getTransferPair(String ref, BufferAllocator allocator, CallBack callBack) To transfer quota responsibility.
ArrowBuf	getValidityBuffer() Gets the underlying buffer associated with validity vector.
long	getValidityBufferAddress() Gets the starting address of the underlying buffer associated with validity vector.
int	getValueCapacity() Get the current value capacity for the vector.
UnionListWriter	getWriter()
int	hashCode(int index) Returns hashCode of element in index with the default hasher.
int	hashCode(int index, ArrowBufHasher hasher) Returns hashCode of element in index with the given hasher.
void	initializeChildrenFromFields(List<Field> children) Initializes the child vectors to be later loaded with loadBuffers.
protected void	invalidateReader()
boolean	isEmpty(int index) Check if element at given index is empty list.
boolean	isNull(int index) Check if element at given index is null.
int	isSet(int index) Same as isNull(int).
void	loadFieldBuffers(ArrowFieldNode fieldNode, List<ArrowBuf> ownBuffers) Load the buffers of this vector with provided source buffers.
TransferPair	makeTransferPair(ValueVector target) Makes a new transfer pair used to transfer underlying buffers.
UnionVector	promoteToUnion()
void	reAlloc() Resize the vector to increase the capacity.
protected void	reallocValidityAndOffsetBuffers()
void	reset() Reset the ValueVector to the initial state without releasing any owned ArrowBuf.
void	setInitialCapacity(int numRecords) Set the initial record capacity.
void	setInitialCapacity(int numRecords, double density) Specialized version of setInitialCapacity() for ListVector.
void	setInitialTotalCapacity(int numRecords, int totalNumberOfElements) Specialized version of setInitialTotalCapacity() for ListVector.
void	setLastSet(int value)
void	setNotNull(int index) Sets the list at index to be not-null.
void	setNull(int index) Sets list at index to be null.
void	setValueCount(int valueCount) Sets the value count for the vector.
int	startNewValue(int index) Start a new value in the list vector.

Methods inherited from class org.apache.arrow.vector.complex.BaseRepeatedValueVector

allocateOffsetBuffer, getInnerValueCount, getInnerValueCountAt, getName, getOffsetBufferValueCapacity, getOffsetVector, getValueCount, iterator, reallocOffsetBuffer, replaceDataVector, size

Methods inherited from class org.apache.arrow.vector.BaseValueVector

checkBufRefs, close, getAllocator, getTransferPair, getValidityBufferSizeFromCount, releaseBuffer, toString, transferBuffer

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.arrow.vector.ValueVector

close, getAllocator, getTransferPair, validate, validateFull

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Field Detail

validityBuffer

protected ArrowBuf validityBuffer

reader

protected UnionListReader reader

field

protected Field field

validityAllocationSizeInBytes

protected int validityAllocationSizeInBytes

lastSet

protected int lastSet

The maximum index that is actually set.

Constructor Detail

ListVector

public ListVector(String name,
                  BufferAllocator allocator,
                  FieldType fieldType,
                  CallBack callBack)

Constructs a new instance.

Parameters:

name - The name of the instance.

allocator - The allocator to use for allocating/reallocating buffers.

fieldType - The type of this list.

callBack - A schema change callback.

ListVector

public ListVector(Field field,
                  BufferAllocator allocator,
                  CallBack callBack)

Constructs a new instance.

Parameters:

field - The field materialized by this vector.

allocator - The allocator to use for allocating/reallocating buffers.

callBack - A schema change callback.

Method Detail

empty

public static ListVector empty(String name,
                               BufferAllocator allocator)

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

setInitialCapacity

public void setInitialCapacity(int numRecords)

Description copied from interface: ValueVector

Set the initial record capacity.

Specified by:

setInitialCapacity in interface ValueVector

Overrides:

setInitialCapacity in class BaseRepeatedValueVector

Parameters:

numRecords - the initial record capacity.

setInitialCapacity

public void setInitialCapacity(int numRecords,
                               double density)

Specialized version of setInitialCapacity() for ListVector. This is used by some callers when they want to explicitly control and be conservative about memory allocated for inner data vector. This is very useful when we are working with memory constraints for a query and have a fixed amount of memory reserved for the record batch. In such cases, we are likely to face OOM or related problems when we reserve memory for a record batch with value count x and do setInitialCapacity(x) such that each vector allocates only what is necessary and not the default amount but the multiplier forces the memory requirement to go beyond what was needed.

Specified by:

setInitialCapacity in interface DensityAwareVector

Overrides:

setInitialCapacity in class BaseRepeatedValueVector

Parameters:

numRecords - value count

density - density of ListVector. Density is the average size of list per position in the List vector. For example, a density value of 10 implies each position in the list vector has a list of 10 values. A density value of 0.1 implies out of 10 positions in the list vector, 1 position has a list of size 1 and remaining positions are null (no lists) or empty lists. This helps in tightly controlling the memory we provision for inner data vector.

setInitialTotalCapacity

public void setInitialTotalCapacity(int numRecords,
                                    int totalNumberOfElements)

Specialized version of setInitialTotalCapacity() for ListVector. This is used by some callers when they want to explicitly control and be conservative about memory allocated for inner data vector. This is very useful when we are working with memory constraints for a query and have a fixed amount of memory reserved for the record batch. In such cases, we are likely to face OOM or related problems when we reserve memory for a record batch with value count x and do setInitialCapacity(x) such that each vector allocates only what is necessary and not the default amount but the multiplier forces the memory requirement to go beyond what was needed.

Overrides:

setInitialTotalCapacity in class BaseRepeatedValueVector

Parameters:

numRecords - value count

totalNumberOfElements - the total number of elements to to allow for in this vector across all records.

getDensity

public double getDensity()

Get the density of this ListVector.

Returns:

density

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)

Load the buffers of this vector with provided source buffers. The caller manages the source buffers and populates them before invoking this method.

Specified by:

loadFieldBuffers in interface FieldVector

Parameters:

fieldNode - the fieldNode indicating the value count

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

getFieldBuffers

public List<ArrowBuf> getFieldBuffers()

Get the buffers belonging to this vector.

Specified by:

getFieldBuffers in interface FieldVector

Returns:

the inner buffers.

getFieldInnerVectors

@Deprecated
public List<BufferBacked> getFieldInnerVectors()

Deprecated. This API will be removed as the current implementations no longer support inner vectors.

Get the inner vectors.

Specified by:

getFieldInnerVectors in interface FieldVector

Returns:

the inner vectors for this field as defined by the TypeLayout

getWriter

public UnionListWriter getWriter()

allocateNew

public void allocateNew()
                 throws OutOfMemoryException

Same as allocateNewSafe().

Specified by:

allocateNew in interface ValueVector

Throws:

OutOfMemoryException - Thrown if no memory can be allocated.

allocateNewSafe

public boolean allocateNewSafe()

Allocate memory for the vector. We internally use a default value count of 4096 to allocate memory for at least these many elements in the vector.

Specified by:

allocateNewSafe in interface ValueVector

Overrides:

allocateNewSafe in class BaseRepeatedValueVector

Returns:

false if memory allocation fails, true otherwise.

allocateValidityBuffer

protected void allocateValidityBuffer(long size)

reAlloc

public void reAlloc()

Resize the vector to increase the capacity. The internal behavior is to double the current value capacity.

Specified by:

reAlloc in interface ValueVector

Overrides:

reAlloc in class BaseRepeatedValueVector

reallocValidityAndOffsetBuffers

protected void reallocValidityAndOffsetBuffers()

copyFromSafe

public void copyFromSafe(int inIndex,
                         int outIndex,
                         ValueVector from)

Same as copyFrom(int, int, ValueVector) except that it handles the case when the capacity of the vector needs to be expanded before copy.

Specified by:

copyFromSafe in interface ValueVector

Overrides:

copyFromSafe in class BaseValueVector

Parameters:

inIndex - position to copy from in source vector

outIndex - position to copy to in this vector

from - source vector

copyFrom

public void copyFrom(int inIndex,
                     int outIndex,
                     ValueVector from)

Copy a cell value from a particular index in source vector to a particular position in this vector.

Specified by:

copyFrom in interface ValueVector

Overrides:

copyFrom in class BaseValueVector

Parameters:

inIndex - position to copy from in source vector

outIndex - position to copy to in this vector

from - source vector

getDataVector

public FieldVector getDataVector()

Get the inner data vector for this list vector.

Specified by:

getDataVector in interface RepeatedValueVector

Overrides:

getDataVector in class BaseRepeatedValueVector

Returns:

data vector

getTransferPair

public TransferPair getTransferPair(String ref,
                                    BufferAllocator allocator)

Description copied from interface: ValueVector

To transfer quota responsibility.

Specified by:

getTransferPair in interface ValueVector

Parameters:

ref - the name of the vector

allocator - the target allocator

Returns:

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

getTransferPair

public TransferPair getTransferPair(Field field,
                                    BufferAllocator allocator)

Description copied from interface: ValueVector

To transfer quota responsibility.

Specified by:

getTransferPair in interface ValueVector

Parameters:

field - the Field object used by the target vector

allocator - the target allocator

Returns:

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

getTransferPair

public TransferPair getTransferPair(String ref,
                                    BufferAllocator allocator,
                                    CallBack callBack)

Description copied from interface: ValueVector

To transfer quota responsibility.

Specified by:

getTransferPair in interface ValueVector

Parameters:

ref - the name of the vector

allocator - the target allocator

callBack - A schema change callback.

Returns:

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

getTransferPair

public TransferPair getTransferPair(Field field,
                                    BufferAllocator allocator,
                                    CallBack callBack)

Description copied from interface: ValueVector

To transfer quota responsibility.

Specified by:

getTransferPair in interface ValueVector

Parameters:

field - the Field object used by the target vector

allocator - the target allocator

callBack - A schema change callback.

Returns:

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

makeTransferPair

public TransferPair makeTransferPair(ValueVector target)

Description copied from interface: ValueVector

Makes a new transfer pair used to transfer underlying buffers.

Specified by:

makeTransferPair in interface ValueVector

Parameters:

target - the target for the transfer

Returns:

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

getValidityBufferAddress

public long getValidityBufferAddress()

Description copied from interface: FieldVector

Gets the starting address of the underlying buffer associated with validity vector.

Specified by:

getValidityBufferAddress in interface FieldVector

Returns:

buffer address

getDataBufferAddress

public long getDataBufferAddress()

Description copied from interface: FieldVector

Gets the starting address of the underlying buffer associated with data vector.

Specified by:

getDataBufferAddress in interface FieldVector

Returns:

buffer address

getOffsetBufferAddress

public long getOffsetBufferAddress()

Description copied from interface: FieldVector

Gets the starting address of the underlying buffer associated with offset vector.

Specified by:

getOffsetBufferAddress in interface FieldVector

Returns:

buffer address

getValidityBuffer

public ArrowBuf getValidityBuffer()

Description copied from interface: ValueVector

Gets the underlying buffer associated with validity vector.

Specified by:

getValidityBuffer in interface ValueVector

Returns:

buffer

getDataBuffer

public ArrowBuf getDataBuffer()

Description copied from interface: ValueVector

Gets the underlying buffer associated with data vector.

Specified by:

getDataBuffer in interface ValueVector

Returns:

buffer

getOffsetBuffer

public ArrowBuf getOffsetBuffer()

Description copied from interface: ValueVector

Gets the underlying buffer associated with offset vector.

Specified by:

getOffsetBuffer in interface ValueVector

Returns:

buffer

hashCode

public int hashCode(int index)

Description copied from interface: ValueVector

Returns hashCode of element in index with the default hasher.

Specified by:

hashCode in interface ValueVector

hashCode

public int hashCode(int index,
                    ArrowBufHasher hasher)

Description copied from interface: ValueVector

Returns hashCode of element in index with the given hasher.

Specified by:

hashCode in interface ValueVector

accept

public <OUT,IN> OUT accept(VectorVisitor<OUT,IN> visitor,
                           IN value)

Description copied from interface: ValueVector

Accept a generic VectorVisitor and return the result.

Specified by:

accept in interface ValueVector

Type Parameters:

OUT - the output result type.

IN - the input data together with visitor.

getReaderImpl

protected FieldReader getReaderImpl()

Description copied from class: BaseValueVector

Each vector has a different reader that implements the FieldReader interface. Overridden methods must make sure to return the correct concrete reader implementation.

Specified by:

getReaderImpl in class BaseValueVector

Returns:

Returns a lambda that initializes a reader when called.

getReader

public UnionListReader getReader()

Description copied from class: BaseValueVector

Default implementation to create a reader for the vector. Depends on the individual vector class' implementation of BaseValueVector.getReaderImpl() to initialize the reader appropriately.

Specified by:

getReader in interface ValueVector

Overrides:

getReader in class BaseValueVector

Returns:

Concrete instance of FieldReader by using double-checked locking.

addOrGetVector

public <T extends ValueVector> AddOrGetResult<T> addOrGetVector(FieldType fieldType)

Initialize the child data vector to field type.

Specified by:

addOrGetVector in interface PromotableVector

Overrides:

addOrGetVector in class BaseRepeatedValueVector

getBufferSize

public int getBufferSize()

Get the size (number of bytes) of underlying buffers used by this vector.

Specified by:

getBufferSize in interface ValueVector

Overrides:

getBufferSize in class BaseRepeatedValueVector

Returns:

size of underlying buffers.

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 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

Overrides:

getBufferSizeFor in class BaseRepeatedValueVector

Parameters:

valueCount - the number of values to assume this vector contains

Returns:

the buffer size if this vector is holding valueCount values

getField

public Field getField()

Description copied from interface: ValueVector

Get information about how this field is materialized.

Specified by:

getField in interface ValueVector

Returns:

the field corresponding to this vector

getMinorType

public Types.MinorType getMinorType()

Specified by:

getMinorType in interface ValueVector

clear

public void clear()

Description copied from interface: ValueVector

Release any owned ArrowBuf and reset the ValueVector to the initial state. If the vector has any child vectors, they will also be cleared.

Specified by:

clear in interface ValueVector

Overrides:

clear in class BaseRepeatedValueVector

reset

public void reset()

Description copied from interface: ValueVector

Reset the ValueVector to the initial state without releasing any owned ArrowBuf. Buffer capacities will remain unchanged and any previous data will be zeroed out. This includes buffers for data, validity, offset, etc. If the vector has any child vectors, they will also be reset.

Specified by:

reset in interface ValueVector

Overrides:

reset in class BaseRepeatedValueVector

getBuffers

public ArrowBuf[] getBuffers(boolean clear)

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

Overrides:

getBuffers in class BaseRepeatedValueVector

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.

promoteToUnion

public UnionVector promoteToUnion()

Specified by:

promoteToUnion in interface PromotableVector

invalidateReader

protected void invalidateReader()

getObject

public List<?> getObject(int index)

Get the element in the list vector at a particular index.

Specified by:

getObject in interface ValueVector

Parameters:

index - position of the element

Returns:

Object at given position

isNull

public boolean isNull(int index)

Check if element at given index is null.

Specified by:

isNull in interface ValueVector

Overrides:

isNull in class BaseRepeatedValueVector

Parameters:

index - position of element

Returns:

true if element at given index is null, false otherwise

isEmpty

public boolean isEmpty(int index)

Check if element at given index is empty list.

Overrides:

isEmpty in class BaseRepeatedValueVector

Parameters:

index - position of element

Returns:

true if element at given index is empty list or NULL, false otherwise

isSet

public int isSet(int index)

Same as isNull(int).

Parameters:

index - position of element

Returns:

1 if element at given index is not null, 0 otherwise

getNullCount

public int getNullCount()

Get the number of elements that are null in the vector.

Specified by:

getNullCount in interface ValueVector

Returns:

the number of null elements.

getValueCapacity

public int getValueCapacity()

Get the current value capacity for the vector.

Specified by:

getValueCapacity in interface ValueVector

Overrides:

getValueCapacity in class BaseRepeatedValueVector

Returns:

number of elements that vector can hold.

setNotNull

public void setNotNull(int index)

Sets the list at index to be not-null. Reallocates validity buffer if index is larger than current capacity.

setNull

public void setNull(int index)

Sets list at index to be null.

Specified by:

setNull in interface FieldVector

Parameters:

index - position in vector

startNewValue

public int startNewValue(int index)

Start a new value in the list vector.

Overrides:

startNewValue in class BaseRepeatedValueVector

Parameters:

index - index of the value to start

endValue

public void endValue(int index,
                     int size)

End the current value.

Parameters:

index - index of the value to end

size - number of elements in the list that was written

setValueCount

public void setValueCount(int valueCount)

Sets the value count for the vector.

Specified by:

setValueCount in interface ValueVector

Overrides:

setValueCount in class BaseRepeatedValueVector

Parameters:

valueCount - value count

setLastSet

public void setLastSet(int value)

getLastSet

public int getLastSet()

getElementStartIndex

public int getElementStartIndex(int index)

Description copied from interface: BaseListVector

Get data vector start index with the given list index.

Specified by:

getElementStartIndex in interface BaseListVector

getElementEndIndex

public int getElementEndIndex(int index)

Description copied from interface: BaseListVector

Get data vector end index with the given list index.

Specified by:

getElementEndIndex in interface BaseListVector