org.apache.arrow.vector.complex

Class MapVector

java.lang.Object

org.apache.arrow.vector.BaseValueVector

org.apache.arrow.vector.complex.BaseRepeatedValueVector

org.apache.arrow.vector.complex.ListVector

org.apache.arrow.vector.complex.MapVector

All Implemented Interfaces:

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

public class MapVector
extends ListVector

A MapVector is used to store entries of key/value pairs. It is a container vector that is composed of a list of struct values with "key" and "value" fields. The MapVector is nullable, but if a map is set at a given index, there must be an entry. In other words, the StructVector data is non-nullable. Also for a given entry, the "key" is non-nullable, however the "value" can be null.

Field Summary

Fields

Modifier and Type	Field and Description
static String	DATA_VECTOR_NAME
static String	KEY_NAME
static String	VALUE_NAME

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

fieldType, lastSet, reader, validityAllocationSizeInBytes, validityBuffer

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

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
MapVector(String name, BufferAllocator allocator, FieldType fieldType, CallBack callBack) Construct a MapVector instance.

Method Summary

Modifier and Type	Method and Description
static MapVector	empty(String name, BufferAllocator allocator, boolean keysSorted) Construct an empty MapVector with no data.
Types.MinorType	getMinorType()
UnionMapReader	getReader() Get the reader for this MapVector instance.
TransferPair	getTransferPair(String ref, BufferAllocator allocator)
TransferPair	getTransferPair(String ref, BufferAllocator allocator, CallBack callBack)
UnionMapWriter	getWriter() Get the writer for this MapVector instance.
void	initializeChildrenFromFields(List<Field> children) Initialize child vectors of the map from the given list of fields.
TransferPair	makeTransferPair(ValueVector target) Makes a new transfer pair used to transfer underlying buffers.

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

accept, addOrGetVector, allocateNew, allocateNewSafe, allocateValidityBuffer, clear, copyFrom, copyFromSafe, empty, endValue, getBuffers, getBufferSize, getBufferSizeFor, getChildrenFromFields, getDataBuffer, getDataBufferAddress, getDataVector, getDensity, getElementEndIndex, getElementStartIndex, getField, getFieldBuffers, getFieldInnerVectors, getLastSet, getNullCount, getObject, getOffsetBuffer, getOffsetBufferAddress, getReaderImpl, getValidityBuffer, getValidityBufferAddress, getValueCapacity, hashCode, hashCode, invalidateReader, isEmpty, isNull, isSet, loadFieldBuffers, promoteToUnion, reAlloc, reallocValidityAndOffsetBuffers, reset, setInitialCapacity, setInitialCapacity, setLastSet, setNotNull, setNull, setValueCount, startNewValue

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Field Detail

KEY_NAME

public static final String KEY_NAME

See Also:

Constant Field Values

VALUE_NAME

public static final String VALUE_NAME

See Also:

Constant Field Values

DATA_VECTOR_NAME

public static final String DATA_VECTOR_NAME

See Also:

Constant Field Values

Constructor Detail

MapVector

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

Construct a MapVector instance.

Parameters:

name - The name of the vector.

allocator - The allocator used for allocating/reallocating buffers.

fieldType - The type definition of the MapVector.

callBack - A schema change callback.

Method Detail

empty

public static MapVector empty(String name,
                              BufferAllocator allocator,
                              boolean keysSorted)

Construct an empty MapVector with no data. Child vectors must be added subsequently.

Parameters:

name - The name of the vector.

allocator - The allocator used for allocating/reallocating buffers.

keysSorted - True if the map keys have been pre-sorted.

Returns:

a new instance of MapVector.

initializeChildrenFromFields

public void initializeChildrenFromFields(List<Field> children)

Initialize child vectors of the map from the given list of fields.

Specified by:

initializeChildrenFromFields in interface FieldVector

Overrides:

initializeChildrenFromFields in class ListVector

Parameters:

children - List of fields that will be children of this MapVector.

getWriter

public UnionMapWriter getWriter()

Get the writer for this MapVector instance.

Overrides:

getWriter in class ListVector

getReader

public UnionMapReader getReader()

Get the reader for this MapVector instance.

Specified by:

getReader in interface ValueVector

Overrides:

getReader in class ListVector

Returns:

Concrete instance of FieldReader by using double-checked locking.

getMinorType

public Types.MinorType getMinorType()

Specified by:

getMinorType in interface ValueVector

Overrides:

getMinorType in class ListVector

getTransferPair

public TransferPair getTransferPair(String ref,
                                    BufferAllocator allocator)

Specified by:

getTransferPair in interface ValueVector

Overrides:

getTransferPair in class ListVector

getTransferPair

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

Specified by:

getTransferPair in interface ValueVector

Overrides:

getTransferPair in class ListVector

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

Overrides:

makeTransferPair in class ListVector

Parameters:

target - the target for the transfer

Returns:

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