org.springframework.data.redis.core

Class ScanCursor<T>

java.lang.Object

org.springframework.data.redis.core.ScanCursor<T>

Type Parameters:

T -

All Implemented Interfaces:

Closeable, AutoCloseable, Iterator<T>, Cursor<T>, org.springframework.data.util.CloseableIterator<T>

Direct Known Subclasses:

KeyBoundCursor

public abstract class ScanCursor<T>
extends Object
implements Cursor<T>

Redis client agnostic Cursor implementation continuously loading additional results from Redis server until reaching its starting point zero.
Note: Please note that the ScanCursor has to be initialized (open() prior to usage. Any failures during scanning will close the cursor and release any associated resources such as connections.

Since:

1.4

Author:

Christoph Strobl, Thomas Darimont, Duobiao Ou, Marl Paluch

Constructor Summary

Constructors

Constructor and Description
ScanCursor() Crates new ScanCursor with id=0 and ScanOptions.NONE
ScanCursor(long cursorId) Crates new ScanCursor with ScanOptions.NONE
ScanCursor(long cursorId, ScanOptions options) Crates new ScanCursor
ScanCursor(ScanOptions options) Crates new ScanCursor with id=0.

Method Summary

Modifier and Type	Method and Description
void	close()
protected void	doClose() Customization hook for cleaning up resources on when calling close().
protected void	doOpen(long cursorId) Customization hook when calling open().
protected abstract ScanIteration<T>	doScan(long cursorId, ScanOptions options) Performs the actual scan command using the native client implementation.
long	getCursorId() Get the reference cursor.
long	getPosition()
boolean	hasNext()
boolean	isClosed()
protected boolean	isFinished(long cursorId) Check whether cursorId is finished.
protected boolean	isOpen()
protected boolean	isReady()
protected T	moveNext(Iterator<T> source) Fetch the next item from the underlying Iterable.
T	next()
ScanCursor<T>	open() Initialize the Cursor prior to usage.
void	remove()

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.springframework.data.util.CloseableIterator

spliterator, stream

Methods inherited from interface java.util.Iterator

forEachRemaining

Constructor Detail

ScanCursor

public ScanCursor()

Crates new ScanCursor with id=0 and ScanOptions.NONE

ScanCursor

public ScanCursor(ScanOptions options)

Crates new ScanCursor with id=0.

Parameters:

options - the scan options to apply.

ScanCursor

public ScanCursor(long cursorId)

Crates new ScanCursor with ScanOptions.NONE

Parameters:

cursorId - the cursor Id.

ScanCursor

public ScanCursor(long cursorId,
                  @Nullable
                  ScanOptions options)

Crates new ScanCursor

Parameters:

cursorId - the cursor Id.

options - Defaulted to ScanOptions.NONE if null.

Method Detail

doScan

protected abstract ScanIteration<T> doScan(long cursorId,
                                           ScanOptions options)

Performs the actual scan command using the native client implementation. The given options are never null.

Parameters:

cursorId -

options -

Returns:

open

public final ScanCursor<T> open()

Initialize the Cursor prior to usage.

Specified by:

open in interface Cursor<T>

Returns:

the opened cursor.

doOpen

protected void doOpen(long cursorId)

Customization hook when calling open().

Parameters:

cursorId -

isFinished

protected boolean isFinished(long cursorId)

Check whether cursorId is finished.

Parameters:

cursorId - the cursor Id

Returns:

true if the cursor is considered finished, false otherwise.s

Since:

2.1

getCursorId

public long getCursorId()

Description copied from interface: Cursor

Get the reference cursor.
NOTE: the id might change while iterating items.

Specified by:

getCursorId in interface Cursor<T>

Returns:

hasNext

public boolean hasNext()

Specified by:

hasNext in interface Iterator<T>

next

public T next()

Specified by:

next in interface Iterator<T>

moveNext

protected T moveNext(Iterator<T> source)

Fetch the next item from the underlying Iterable.

Parameters:

source -

Returns:

remove

public void remove()

Specified by:

remove in interface Iterator<T>

close

public final void close()

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Specified by:

close in interface org.springframework.data.util.CloseableIterator<T>

doClose

protected void doClose()

Customization hook for cleaning up resources on when calling close().

isClosed

public boolean isClosed()

Specified by:

isClosed in interface Cursor<T>

Returns:

true if cursor closed.

isReady

protected final boolean isReady()

isOpen

protected final boolean isOpen()

getPosition

public long getPosition()

Specified by:

getPosition in interface Cursor<T>

Returns:

the current position of the cursor.