uk.ac.starlink.parquet

Interface InputColumn<T>

public interface InputColumn<T>

Provides information about a readable column in a parquet file.

Since:

24 Feb 2021

Author:

Mark Taylor

Method Summary

Modifier and Type	Method and Description
Decoder<T>	createDecoder() Returns a decoder that can read column values from the file.
org.apache.parquet.column.ColumnDescriptor	getColumnDescriptor() Parquet column descriptor applying to column.
Class<T>	getContentClass() Class of object that is read from column data.
DomainMapper	getDomainMapper() Returns a domain mapper if there is one.
boolean	isNullable() Indicates whether null values are a possibility.

Method Detail

getContentClass

Class<T> getContentClass()

Class of object that is read from column data.

Returns:

content class

getColumnDescriptor

org.apache.parquet.column.ColumnDescriptor getColumnDescriptor()

Parquet column descriptor applying to column.

Returns:

descriptor

isNullable

boolean isNullable()

Indicates whether null values are a possibility.

Returns:

false if the column is known to contain no null values

getDomainMapper

DomainMapper getDomainMapper()

Returns a domain mapper if there is one.

Returns:

domain mapper, or null

createDecoder

Decoder<T> createDecoder()

Returns a decoder that can read column values from the file.

Returns:

decoder