Class ReaderColumns

java.lang.Object

io.trino.plugin.hive.ReaderColumns

public class ReaderColumns
extends Object

Stores a mapping between - the projected columns required by a connector level pagesource and - the columns supplied by format-specific page source

Currently used in HivePageSource, io.trino.plugin.iceberg.IcebergPageSource, and io.trino.plugin.deltalake.DeltaLakePageSource.

Constructor Summary

Constructors

Constructor	Description
ReaderColumns(List<? extends ColumnHandle> readerColumns, List<Integer> readerBlockIndices)

Method Summary

Modifier and Type	Method	Description
List<ColumnHandle>	get()	returns the actual list of columns being read by underlying page source or record cursor in order.
ColumnHandle	getForColumnAt(int index)	For a column required by the wrapper page source, returns the column read by the delegate page source or record cursor.
int	getPositionForColumnAt(int index)	For a channel expected by wrapper page source, returns the channel index in the underlying page source or record cursor.

Methods inherited from class java.lang.Object

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

Constructor Details

ReaderColumns

public ReaderColumns(List<? extends ColumnHandle> readerColumns,
 List<Integer> readerBlockIndices)

Method Details

getForColumnAt

public ColumnHandle getForColumnAt(int index)

For a column required by the wrapper page source, returns the column read by the delegate page source or record cursor.

getPositionForColumnAt

public int getPositionForColumnAt(int index)

For a channel expected by wrapper page source, returns the channel index in the underlying page source or record cursor.

get

public List<ColumnHandle> get()

returns the actual list of columns being read by underlying page source or record cursor in order.