Package org.apache.drill.exec.physical.resultSet.model

Class ReaderIndex

java.lang.Object

org.apache.drill.exec.physical.resultSet.model.ReaderIndex

All Implemented Interfaces:

ColumnReaderIndex

Direct Known Subclasses:

DirectRowIndex, HyperRowIndex, IndirectRowIndex

public abstract class ReaderIndex
extends Object
implements ColumnReaderIndex

Row set index base class used when indexing rows within a row set for a row set reader. Keeps track of the current position, which starts before the first row, meaning that the client must call next() to advance to the first row.

Field Summary

Fields

Modifier and Type	Field	Description
protected int	position
protected final Supplier<Integer>	rowCount

Constructor Summary

Constructors

Constructor	Description
ReaderIndex(Supplier<Integer> rowCount)

Method Summary

Modifier and Type	Method	Description
boolean	hasNext()	Reports if the index has another item.
int	logicalIndex()	Ordinal index within the batch or array.
boolean	next()	Advances the index to the next position.
void	set(int index)
int	size()	Return the number of items that this index indexes: top-level record count for the root index; total element count for nested arrays.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.drill.exec.vector.accessor.ColumnReaderIndex

hyperVectorIndex, offset

Field Details

position

protected int position

rowCount

protected final Supplier<Integer> rowCount

Constructor Details

ReaderIndex

public ReaderIndex(Supplier<Integer> rowCount)

Method Details

set

public void set(int index)

logicalIndex

public int logicalIndex()

Description copied from interface: ColumnReaderIndex

Ordinal index within the batch or array. Increments from -1. (The position before the first item.) Identifies the logical row number of top-level records, or the array element for arrays. Actual physical index may be different if an indirection layer is in use.

Specified by:

logicalIndex in interface ColumnReaderIndex

Returns:

logical read index

size

public int size()

Description copied from interface: ColumnReaderIndex

Return the number of items that this index indexes: top-level record count for the root index; total element count for nested arrays.

Specified by:

size in interface ColumnReaderIndex

Returns:

element count at this index level

next

public boolean next()

Description copied from interface: ColumnReaderIndex

Advances the index to the next position. Used:

• At the top level for normal readers or
<liAt a nested level for implicit join readers, and
• An each array level to iterate over arrays.

Specified by:

next in interface ColumnReaderIndex

Returns:

true if another value is available, false if EOF

hasNext

public boolean hasNext()

Description copied from interface: ColumnReaderIndex

Reports if the index has another item.

Specified by:

hasNext in interface ColumnReaderIndex

Returns:

if more rows remain. That is, if a call to ColumnReaderIndex.next() would return true.