io.lettuce.core

Class ReadFrom

java.lang.Object

io.lettuce.core.ReadFrom

public abstract class ReadFrom
extends Object

Defines from which Redis nodes data is read.

Since:

4.0

Author:

Mark Paluch, Ryosuke Hasebe

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	ReadFrom.Nodes Descriptor of nodes that are available for the current read operation.

Field Summary

Fields

Modifier and Type	Field and Description
static ReadFrom	ANY Setting to read from any node.
static ReadFrom	MASTER Setting to read from the master only.
static ReadFrom	MASTER_PREFERRED Setting to read preferred from the master and fall back to a replica if the master is not available.
static ReadFrom	NEAREST Setting to read from the nearest node.
static ReadFrom	REPLICA Setting to read from the replica only.
static ReadFrom	REPLICA_PREFERRED Setting to read preferred from replica and fall back to master if no replica is not available.
static ReadFrom	SLAVE Deprecated. renamed to REPLICA.
static ReadFrom	SLAVE_PREFERRED Deprecated. Renamed to REPLICA_PREFERRED.

Constructor Summary

Constructors

Constructor and Description
ReadFrom()

Method Summary

Modifier and Type	Method and Description
abstract List<RedisNodeDescription>	select(ReadFrom.Nodes nodes) Chooses the nodes from the matching Redis nodes that match this read selector.
static ReadFrom	valueOf(String name) Retrieve the ReadFrom preset by name.

Methods inherited from class java.lang.Object

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

Field Detail

MASTER

public static final ReadFrom MASTER

Setting to read from the master only.

MASTER_PREFERRED

public static final ReadFrom MASTER_PREFERRED

Setting to read preferred from the master and fall back to a replica if the master is not available.

REPLICA_PREFERRED

public static final ReadFrom REPLICA_PREFERRED

Setting to read preferred from replica and fall back to master if no replica is not available.

Since:

5.2

SLAVE_PREFERRED

@Deprecated
public static final ReadFrom SLAVE_PREFERRED

Deprecated. Renamed to REPLICA_PREFERRED.

Setting to read preferred from replicas and fall back to master if no replica is not available.

Since:

4.4

REPLICA

public static final ReadFrom REPLICA

Setting to read from the replica only.

Since:

5.2

SLAVE

@Deprecated
public static final ReadFrom SLAVE

Deprecated. renamed to REPLICA.

Setting to read from the replica only.

NEAREST

public static final ReadFrom NEAREST

Setting to read from the nearest node.

ANY

public static final ReadFrom ANY

Setting to read from any node.

Since:

5.2

Constructor Detail

ReadFrom

public ReadFrom()

Method Detail

select

public abstract List<RedisNodeDescription> select(ReadFrom.Nodes nodes)

Chooses the nodes from the matching Redis nodes that match this read selector.

Parameters:

nodes - set of nodes that are suitable for reading

Returns:

List of RedisNodeDescriptions that are selected for reading

valueOf

public static ReadFrom valueOf(String name)

Retrieve the ReadFrom preset by name.

Parameters:

name - the name of the read from setting

Returns:

the ReadFrom preset

Throws:

IllegalArgumentException - if name is empty, null or the ReadFrom preset is unknown.