net.spy.memcached

Class KetamaNodeLocator

java.lang.Object

net.spy.memcached.compat.SpyObject

net.spy.memcached.KetamaNodeLocator

All Implemented Interfaces:

NodeLocator

public final class KetamaNodeLocator
extends SpyObject
implements NodeLocator

This is an implementation of the Ketama consistent hash strategy from last.fm. This implementation may not be compatible with libketama as hashing is considered separate from node location. Note that this implementation does not currently supported weighted nodes.

See Also:

RJ's blog post

Constructor Summary

Constructors

Constructor and Description
KetamaNodeLocator(java.util.List<MemcachedNode> nodes, HashAlgorithm alg) Create a new KetamaNodeLocator using specified nodes and the specifed hash algorithm.
KetamaNodeLocator(java.util.List<MemcachedNode> nodes, HashAlgorithm alg, KetamaNodeKeyFormatter.Format nodeKeyFormat, java.util.Map<java.net.InetSocketAddress,java.lang.Integer> weights) Create a new KetamaNodeLocator with specific nodes, hash, node key format, and weight
KetamaNodeLocator(java.util.List<MemcachedNode> nodes, HashAlgorithm alg, KetamaNodeLocatorConfiguration conf) Create a new KetamaNodeLocator using specified nodes and the specifed hash algorithm and configuration.
KetamaNodeLocator(java.util.List<MemcachedNode> nodes, HashAlgorithm alg, java.util.Map<java.net.InetSocketAddress,java.lang.Integer> nodeWeights, KetamaNodeLocatorConfiguration configuration) Create a new KetamaNodeLocator with specific nodes, hash, node key format, and weight

Method Summary

Modifier and Type	Method and Description
java.util.Collection<MemcachedNode>	getAll() Get all memcached nodes.
protected java.util.TreeMap<java.lang.Long,MemcachedNode>	getKetamaNodes()
MemcachedNode	getPrimary(java.lang.String k) Get the primary location for the given key.
NodeLocator	getReadonlyCopy() Create a read-only copy of this NodeLocator.
java.util.Iterator<MemcachedNode>	getSequence(java.lang.String k) Get an iterator over the sequence of nodes that make up the backup locations for a given key.
protected void	setKetamaNodes(java.util.List<MemcachedNode> nodes) Setup the KetamaNodeLocator with the list of nodes it should use.
void	updateLocator(java.util.List<MemcachedNode> nodes) Update locator status.

Methods inherited from class net.spy.memcached.compat.SpyObject

getLogger

Methods inherited from class java.lang.Object

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

Constructor Detail

KetamaNodeLocator

public KetamaNodeLocator(java.util.List<MemcachedNode> nodes,
                         HashAlgorithm alg)

Create a new KetamaNodeLocator using specified nodes and the specifed hash algorithm.

Parameters:

nodes - The List of nodes to use in the Ketama consistent hash continuum

alg - The hash algorithm to use when choosing a node in the Ketama consistent hash continuum

KetamaNodeLocator

public KetamaNodeLocator(java.util.List<MemcachedNode> nodes,
                         HashAlgorithm alg,
                         KetamaNodeKeyFormatter.Format nodeKeyFormat,
                         java.util.Map<java.net.InetSocketAddress,java.lang.Integer> weights)

Create a new KetamaNodeLocator with specific nodes, hash, node key format, and weight

Parameters:

nodes - The List of nodes to use in the Ketama consistent hash continuum

alg - The hash algorithm to use when choosing a node in the Ketama consistent hash continuum

nodeKeyFormat - the format used to name the nodes in Ketama, either SPYMEMCACHED or LIBMEMCACHED

weights - node weights for ketama, a map from InetSocketAddress to weight as Integer

KetamaNodeLocator

public KetamaNodeLocator(java.util.List<MemcachedNode> nodes,
                         HashAlgorithm alg,
                         KetamaNodeLocatorConfiguration conf)

Create a new KetamaNodeLocator using specified nodes and the specifed hash algorithm and configuration.

Parameters:

nodes - The List of nodes to use in the Ketama consistent hash continuum

alg - The hash algorithm to use when choosing a node in the Ketama consistent hash continuum

conf -

KetamaNodeLocator

public KetamaNodeLocator(java.util.List<MemcachedNode> nodes,
                         HashAlgorithm alg,
                         java.util.Map<java.net.InetSocketAddress,java.lang.Integer> nodeWeights,
                         KetamaNodeLocatorConfiguration configuration)

Create a new KetamaNodeLocator with specific nodes, hash, node key format, and weight

Parameters:

nodes - The List of nodes to use in the Ketama consistent hash continuum

alg - The hash algorithm to use when choosing a node in the Ketama consistent hash continuum

weights - node weights for ketama, a map from InetSocketAddress to weight as Integer

configuration - node locator configuration

Method Detail

getAll

public java.util.Collection<MemcachedNode> getAll()

Description copied from interface: NodeLocator

Get all memcached nodes. This is useful for broadcasting messages.

Specified by:

getAll in interface NodeLocator

getPrimary

public MemcachedNode getPrimary(java.lang.String k)

Description copied from interface: NodeLocator

Get the primary location for the given key.

Specified by:

getPrimary in interface NodeLocator

Parameters:

k - the object key

Returns:

the QueueAttachment containing the primary storage for a key

getSequence

public java.util.Iterator<MemcachedNode> getSequence(java.lang.String k)

Description copied from interface: NodeLocator

Get an iterator over the sequence of nodes that make up the backup locations for a given key.

Specified by:

getSequence in interface NodeLocator

Parameters:

k - the object key

Returns:

the sequence of backup nodes.

getReadonlyCopy

public NodeLocator getReadonlyCopy()

Description copied from interface: NodeLocator

Create a read-only copy of this NodeLocator.

Specified by:

getReadonlyCopy in interface NodeLocator

updateLocator

public void updateLocator(java.util.List<MemcachedNode> nodes)

Description copied from interface: NodeLocator

Update locator status.

Specified by:

updateLocator in interface NodeLocator

Parameters:

nodes - New locator nodes.

getKetamaNodes

protected java.util.TreeMap<java.lang.Long,MemcachedNode> getKetamaNodes()

Returns:

the ketamaNodes

setKetamaNodes

protected void setKetamaNodes(java.util.List<MemcachedNode> nodes)

Setup the KetamaNodeLocator with the list of nodes it should use.

Parameters:

nodes - a List of MemcachedNodes for this KetamaNodeLocator to use in its continuum