Class MVSortedTempResult

java.lang.Object

org.h2.mvstore.db.MVTempResult

org.h2.mvstore.db.MVSortedTempResult

All Implemented Interfaces:

ResultExternal

class MVSortedTempResult
extends MVTempResult

Sorted temporary result.

This result is used for distinct and/or sorted results.

Field Summary

Fields

Modifier and Type	Field	Description
private Value[]	current	Current value for the next() method.
private Cursor<ValueRow,Long>	cursor	Cursor for the next() method.
private final boolean	distinct	Whether this result is a standard distinct result.
private final int[]	distinctIndexes	Distinct indexes for DISTINCT ON results.
private MVMap<ValueRow,Value>	index	Optional index.
private final int[]	indexes	Mapping of indexes of columns to its positions in the store, or null if columns are not reordered.
private final MVMap<ValueRow,Long>	map	Map with rows as keys and counts of duplicate rows as values.
private ValueDataType	orderedDistinctOnType	Used for DISTINCT ON in presence of ORDER BY.
private long	valueCount	Count of remaining duplicate rows for the next() method.

Fields inherited from class MVTempResult

childCount, closed, expressions, parent, resultColumnCount, rowCount, store, visibleColumnCount

Constructor Summary

Constructors

Modifier	Constructor	Description
(package private)	MVSortedTempResult(Database database, Expression[] expressions, boolean distinct, int[] distinctIndexes, int visibleColumnCount, int resultColumnCount, SortOrder sort)	Creates a new sorted temporary result.
private	MVSortedTempResult(MVSortedTempResult parent)	Creates a shallow copy of the result.

Method Summary

Modifier and Type	Method	Description
int	addRow(Value[] values)	Add a row to this object.
boolean	contains(Value[] values)	Check if the given row exists in this object.
ResultExternal	createShallowCopy()	Create a shallow copy of this object if possible.
private ValueRow	getKey(Value[] values)	Reorder values if required and convert them into ValueRow.
private Value[]	getValue(Value[] key)	Reorder values back if required.
Value[]	next()	Get the next row from the result.
int	removeRow(Value[] values)	Remove the row with the given values from this object if such a row exists.
void	reset()	Reset the current position of this object.

Methods inherited from class MVTempResult

addRows, close, of

Methods inherited from class Object

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

Field Details

distinct

private final boolean distinct

Whether this result is a standard distinct result.

distinctIndexes

private final int[] distinctIndexes

Distinct indexes for DISTINCT ON results.

indexes

private final int[] indexes

Mapping of indexes of columns to its positions in the store, or null if columns are not reordered.

map

private final MVMap<ValueRow,Long> map

Map with rows as keys and counts of duplicate rows as values. If this map is distinct all values are 1.

index

private MVMap<ValueRow,Value> index

Optional index. This index is created only if result is distinct and columnCount != distinctColumnCount or if contains(Value[]) method is invoked. Only the root result should have an index if required.

orderedDistinctOnType

private ValueDataType orderedDistinctOnType

Used for DISTINCT ON in presence of ORDER BY.

cursor

private Cursor<ValueRow,Long> cursor

Cursor for the next() method.

current

private Value[] current

Current value for the next() method. Used in non-distinct results with duplicate rows.

valueCount

private long valueCount

Count of remaining duplicate rows for the next() method. Used in non-distinct results.

Constructor Details

MVSortedTempResult

private MVSortedTempResult(MVSortedTempResult parent)

Creates a shallow copy of the result.

Parameters:

parent - parent result

MVSortedTempResult

MVSortedTempResult(Database database,
 Expression[] expressions,
 boolean distinct,
 int[] distinctIndexes,
 int visibleColumnCount,
 int resultColumnCount,
 SortOrder sort)

Creates a new sorted temporary result.

Parameters:

database - database

expressions - column expressions

distinct - whether this result should be distinct

distinctIndexes - indexes of distinct columns for DISTINCT ON results

visibleColumnCount - count of visible columns

resultColumnCount - the number of columns including visible columns and additional virtual columns for ORDER BY and DISTINCT ON clauses

sort - sort order, or null if this result does not need any sorting

Method Details

addRow

public int addRow(Value[] values)

Description copied from interface: ResultExternal

Add a row to this object.

Parameters:

values - the row to add

Returns:

the new number of rows in this object

contains

public boolean contains(Value[] values)

Description copied from interface: ResultExternal

Check if the given row exists in this object.

Parameters:

values - the row

Returns:

true if it exists

createShallowCopy

public ResultExternal createShallowCopy()

Description copied from interface: ResultExternal

Create a shallow copy of this object if possible.

Returns:

the shallow copy, or null

getKey

private ValueRow getKey(Value[] values)

Reorder values if required and convert them into ValueRow.

Parameters:

values - values

Returns:

ValueRow for maps

getValue

private Value[] getValue(Value[] key)

Reorder values back if required.

Parameters:

key - reordered values

Returns:

original values

next

public Value[] next()

Description copied from interface: ResultExternal

Get the next row from the result.

Returns:

the next row or null

removeRow

public int removeRow(Value[] values)

Description copied from interface: ResultExternal

Remove the row with the given values from this object if such a row exists.

Parameters:

values - the row

Returns:

the new row count

reset

public void reset()

Description copied from interface: ResultExternal

Reset the current position of this object.