Package org.apache.arrow.vector.dictionary

Class StructSubfieldEncoder

java.lang.Object

org.apache.arrow.vector.dictionary.StructSubfieldEncoder

public class StructSubfieldEncoder
extends Object

Sub fields encoder/decoder for Dictionary encoded StructVector. Notes that child vectors within struct vector can either be dictionary encodable or not.

Constructor Summary

Constructors

Constructor	Description
StructSubfieldEncoder(BufferAllocator allocator, DictionaryProvider.MapDictionaryProvider provider)	Construct an instance.
StructSubfieldEncoder(BufferAllocator allocator, DictionaryProvider.MapDictionaryProvider provider, ArrowBufHasher hasher)	Construct an instance.

Method Summary

Modifier and Type	Method	Description
StructVector	decode(StructVector vector)	Decodes a dictionary subfields encoded vector using the provided dictionary.
static StructVector	decode(StructVector vector, DictionaryProvider.MapDictionaryProvider provider, BufferAllocator allocator)	Decodes a dictionary subfields encoded vector using the provided dictionary.
StructVector	encode(StructVector vector, Map<Integer,Long> columnToDictionaryId)	Dictionary encodes subfields for complex vector with a provided dictionary.

Methods inherited from class java.lang.Object

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

Constructor Details

StructSubfieldEncoder

public StructSubfieldEncoder(BufferAllocator allocator,
 DictionaryProvider.MapDictionaryProvider provider)

Construct an instance.

StructSubfieldEncoder

public StructSubfieldEncoder(BufferAllocator allocator,
 DictionaryProvider.MapDictionaryProvider provider,
 ArrowBufHasher hasher)

Construct an instance.

Method Details

encode

public StructVector encode(StructVector vector,
 Map<Integer,Long> columnToDictionaryId)

Dictionary encodes subfields for complex vector with a provided dictionary. The dictionary must contain all values in the sub fields vector.

Parameters:

vector - vector to encode

columnToDictionaryId - the mappings between child vector index and dictionary id. A null dictionary id indicates the child vector is not encodable.

Returns:

dictionary encoded vector

decode

public StructVector decode(StructVector vector)

Decodes a dictionary subfields encoded vector using the provided dictionary.

decode(StructVector, DictionaryProvider.MapDictionaryProvider, BufferAllocator) should be used instead if only decoding is required as it can avoid building the DictionaryHashTable which only makes sense when encoding.

Parameters:

vector - dictionary encoded vector, its child vector must be int type

Returns:

vector with values restored from dictionary

decode

public static StructVector decode(StructVector vector,
 DictionaryProvider.MapDictionaryProvider provider,
 BufferAllocator allocator)

Decodes a dictionary subfields encoded vector using the provided dictionary.

Parameters:

vector - dictionary encoded vector, its data vector must be int type

provider - dictionary provider used to decode the values

allocator - allocator the decoded values use

Returns:

vector with values restored from dictionary