Module org.apache.arrow.vector

Package org.apache.arrow.vector.util

Class DictionaryUtility

java.lang.Object

org.apache.arrow.vector.util.DictionaryUtility

public class DictionaryUtility
extends Object

Utility methods for working with Dictionaries used in Dictionary encodings.

Method Summary

Modifier and Type	Method	Description
static boolean	needConvertToMessageFormat(Field field)	Checks if it is required to convert the field to message format.
static Field	toMemoryFormat(Field field, BufferAllocator allocator, Map<Long,Dictionary> dictionaries)	Convert field and child fields that have a dictionary encoding to memory format, so fields have the index type.
static Field	toMessageFormat(Field field, DictionaryProvider provider, Set<Long> dictionaryIdsUsed)	Convert field and child fields that have a dictionary encoding to message format, so fields have the dictionary type.

Methods inherited from class java.lang.Object

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

Method Details

toMessageFormat

public static Field toMessageFormat(Field field,
 DictionaryProvider provider,
 Set<Long> dictionaryIdsUsed)

Convert field and child fields that have a dictionary encoding to message format, so fields have the dictionary type.

NOTE: in the message format, fields have the dictionary type in the memory format, they have the index type

needConvertToMessageFormat

public static boolean needConvertToMessageFormat(Field field)

Checks if it is required to convert the field to message format.

Parameters:

field - the field to check.

Returns:

true if a conversion is required, and false otherwise.

toMemoryFormat

public static Field toMemoryFormat(Field field,
 BufferAllocator allocator,
 Map<Long,Dictionary> dictionaries)

Convert field and child fields that have a dictionary encoding to memory format, so fields have the index type.