org.h2.result

Class LazyResult

java.lang.Object

org.h2.result.LazyResult

All Implemented Interfaces:

java.lang.AutoCloseable, ResultInterface

public abstract class LazyResult
extends java.lang.Object
implements ResultInterface

Lazy execution support for queries.

Constructor Summary

Constructors

Constructor and Description
LazyResult(Expression[] expressions)

Method Summary

Methods

Modifier and Type	Method and Description
void	close() Close the result and delete any temporary files
ResultInterface	createShallowCopy(SessionInterface targetSession) Create a shallow copy of the result set.
Value[]	currentRow() Get the current row.
protected abstract Value[]	fetchNextRow() Fetch next row or null if none available.
java.lang.String	getAlias(int i) Get the column alias name for the column.
java.lang.String	getColumnName(int i) Get the column name.
TypeInfo	getColumnType(int i) Get the column data type.
int	getFetchSize() Get the current fetch size for this result set.
int	getNullable(int i) Check if this column is nullable.
int	getRowCount() Get the number of rows in this object.
int	getRowId() Get the current row id, starting with 0.
java.lang.String	getSchemaName(int i) Get the schema name for the column, if one exists.
java.lang.String	getTableName(int i) Get the table name for the column, if one exists.
boolean	hasNext() Check if this result has more rows to fetch.
boolean	isAfterLast() Check if the current position is after last row.
boolean	isAutoIncrement(int i) Check if this is an auto-increment column.
boolean	isClosed() Check if this result set is closed.
boolean	isLazy() Check if this a lazy execution result.
boolean	needToClose() Check if this result set should be closed, for example because it is buffered using a temporary file.
boolean	next() Go to the next row.
void	reset() Go to the beginning of the result, that means before the first row.
void	setFetchSize(int fetchSize) Set the fetch size for this result set.
void	setLimit(int limit)
boolean	skip() Go to the next row and skip it.
protected boolean	skipNextRow() Skip next row.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.h2.result.ResultInterface

getVisibleColumnCount

Constructor Detail

LazyResult

public LazyResult(Expression[] expressions)

Method Detail

setLimit

public void setLimit(int limit)

isLazy

public boolean isLazy()

Description copied from interface: ResultInterface

Check if this a lazy execution result.

Specified by:

isLazy in interface ResultInterface

Returns:

true if it is a lazy result

reset

public void reset()

Description copied from interface: ResultInterface

Go to the beginning of the result, that means before the first row.

Specified by:

reset in interface ResultInterface

currentRow

public Value[] currentRow()

Description copied from interface: ResultInterface

Get the current row.

Specified by:

currentRow in interface ResultInterface

Returns:

the row

next

public boolean next()

Description copied from interface: ResultInterface

Go to the next row.

Specified by:

next in interface ResultInterface

Returns:

true if a row exists

skip

public boolean skip()

Go to the next row and skip it.

Returns:

true if a row exists

hasNext

public boolean hasNext()

Description copied from interface: ResultInterface

Check if this result has more rows to fetch.

Specified by:

hasNext in interface ResultInterface

Returns:

true if it has

fetchNextRow

protected abstract Value[] fetchNextRow()

Fetch next row or null if none available.

Returns:

next row or null

skipNextRow

protected boolean skipNextRow()

Skip next row.

Returns:

true if next row was available

isAfterLast

public boolean isAfterLast()

Description copied from interface: ResultInterface

Check if the current position is after last row.

Specified by:

isAfterLast in interface ResultInterface

Returns:

true if after last

getRowId

public int getRowId()

Description copied from interface: ResultInterface

Get the current row id, starting with 0. -1 is returned when next() was not called yet.

Specified by:

getRowId in interface ResultInterface

Returns:

the row id

getRowCount

public int getRowCount()

Description copied from interface: ResultInterface

Get the number of rows in this object.

Specified by:

getRowCount in interface ResultInterface

Returns:

the number of rows

needToClose

public boolean needToClose()

Description copied from interface: ResultInterface

Check if this result set should be closed, for example because it is buffered using a temporary file.

Specified by:

needToClose in interface ResultInterface

Returns:

true if close should be called.

isClosed

public boolean isClosed()

Description copied from interface: ResultInterface

Check if this result set is closed.

Specified by:

isClosed in interface ResultInterface

Returns:

true if it is

close

public void close()

Description copied from interface: ResultInterface

Close the result and delete any temporary files

Specified by:

close in interface java.lang.AutoCloseable

Specified by:

close in interface ResultInterface

getAlias

public java.lang.String getAlias(int i)

Description copied from interface: ResultInterface

Get the column alias name for the column.

Specified by:

getAlias in interface ResultInterface

Parameters:

i - the column number (starting with 0)

Returns:

the alias name

getSchemaName

public java.lang.String getSchemaName(int i)

Description copied from interface: ResultInterface

Get the schema name for the column, if one exists.

Specified by:

getSchemaName in interface ResultInterface

Parameters:

i - the column number (starting with 0)

Returns:

the schema name or null

getTableName

public java.lang.String getTableName(int i)

Description copied from interface: ResultInterface

Get the table name for the column, if one exists.

Specified by:

getTableName in interface ResultInterface

Parameters:

i - the column number (starting with 0)

Returns:

the table name or null

getColumnName

public java.lang.String getColumnName(int i)

Description copied from interface: ResultInterface

Get the column name.

Specified by:

getColumnName in interface ResultInterface

Parameters:

i - the column number (starting with 0)

Returns:

the column name

getColumnType

public TypeInfo getColumnType(int i)

Description copied from interface: ResultInterface

Get the column data type.

Specified by:

getColumnType in interface ResultInterface

Parameters:

i - the column number (starting with 0)

Returns:

the column data type

isAutoIncrement

public boolean isAutoIncrement(int i)

Description copied from interface: ResultInterface

Check if this is an auto-increment column.

Specified by:

isAutoIncrement in interface ResultInterface

Parameters:

i - the column number (starting with 0)

Returns:

true for auto-increment columns

getNullable

public int getNullable(int i)

Description copied from interface: ResultInterface

Check if this column is nullable.

Specified by:

getNullable in interface ResultInterface

Parameters:

i - the column number (starting with 0)

Returns:

Column.NULLABLE_*

setFetchSize

public void setFetchSize(int fetchSize)

Description copied from interface: ResultInterface

Set the fetch size for this result set.

Specified by:

setFetchSize in interface ResultInterface

Parameters:

fetchSize - the new fetch size

getFetchSize

public int getFetchSize()

Description copied from interface: ResultInterface

Get the current fetch size for this result set.

Specified by:

getFetchSize in interface ResultInterface

Returns:

the fetch size

createShallowCopy

public ResultInterface createShallowCopy(SessionInterface targetSession)

Description copied from interface: ResultInterface

Create a shallow copy of the result set. The data and a temporary table (if there is any) is not copied.

Specified by:

createShallowCopy in interface ResultInterface

Parameters:

targetSession - the session of the copy

Returns:

the copy if possible, or null if copying is not possible