org.apache.ignite.internal.processors.platform.cache.affinity

Class PlatformAffinityFunction

java.lang.Object

org.apache.ignite.internal.processors.platform.cache.affinity.PlatformAffinityFunction

All Implemented Interfaces:

Externalizable, Serializable, AffinityFunction, LifecycleAware

public class PlatformAffinityFunction
extends Object
implements AffinityFunction, Externalizable, LifecycleAware

Platform AffinityFunction.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
PlatformAffinityFunction() Ctor for serialization.
PlatformAffinityFunction(Object func, int partitions, byte overrideFlags, AffinityFunction baseFunc) Ctor.

Method Summary

Modifier and Type	Method and Description
List<List<ClusterNode>>	assignPartitions(AffinityFunctionContext affCtx) Gets affinity nodes for a partition.
AffinityFunction	getBaseFunc() Gets the base func.
byte	getOverrideFlags() Gets the override flags.
Object	getUserFunc() Gets the user func object.
int	partition(Object key) Gets partition number for a given key starting from 0.
int	partitions() Gets total number of partitions available.
void	readExternal(ObjectInput in)
void	removeNode(UUID nodeId) Removes node from affinity.
void	reset() Resets cache affinity to its initial state.
void	setIgnite(Ignite ignite) Injects the Ignite.
void	start() Starts grid component, called on grid start.
void	stop() Stops grid component, called on grid shutdown.
void	writeExternal(ObjectOutput out)

Methods inherited from class java.lang.Object

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

Constructor Detail

PlatformAffinityFunction

public PlatformAffinityFunction()

Ctor for serialization.

PlatformAffinityFunction

public PlatformAffinityFunction(Object func,
                                int partitions,
                                byte overrideFlags,
                                AffinityFunction baseFunc)

Ctor.

Parameters:

func - User fun object.

partitions - Number of partitions.

Method Detail

getUserFunc

public Object getUserFunc()

Gets the user func object.

Returns:

User func object.

getBaseFunc

public AffinityFunction getBaseFunc()

Gets the base func.

Returns:

Base func.

getOverrideFlags

public byte getOverrideFlags()

Gets the override flags.

Returns:

The override flags

reset

public void reset()

Resets cache affinity to its initial state. This method will be called by the system any time the affinity has been sent to remote node where it has to be reinitialized. If your implementation of affinity function has no initialization logic, leave this method empty.

Specified by:

reset in interface AffinityFunction

partitions

public int partitions()

Gets total number of partitions available. All caches should always provide correct partition count which should be the same on all participating nodes. Note that partitions should always be numbered from 0 inclusively to N exclusively without any gaps.

Specified by:

partitions in interface AffinityFunction

Returns:

Total partition count.

partition

public int partition(Object key)

Gets partition number for a given key starting from 0. Partitioned caches should make sure that keys are about evenly distributed across all partitions from 0 to partition count for best performance.

Note that for fully replicated caches it is possible to segment key sets among different grid node groups. In that case each node group should return a unique partition number. However, unlike partitioned cache, mappings of keys to nodes in replicated caches are constant and a node cannot migrate from one partition to another.

Specified by:

partition in interface AffinityFunction

Parameters:

key - Key to get partition for.

Returns:

Partition number for a given key.

assignPartitions

public List<List<ClusterNode>> assignPartitions(AffinityFunctionContext affCtx)

Gets affinity nodes for a partition. In case of replicated cache, all returned nodes are updated in the same manner. In case of partitioned cache, the returned list should contain only the primary and back up nodes with primary node being always first.

Note that partitioned affinity must obey the following contract: given that node N is primary for some key K, if any other node(s) leave grid and no node joins grid, node N will remain primary for key K.

Specified by:

assignPartitions in interface AffinityFunction

Parameters:

affCtx - Affinity function context. Will provide all required information to calculate new partition assignments.

Returns:

Unmodifiable list indexed by partition number. Each element of array is a collection in which first node is a primary node and other nodes are backup nodes.

removeNode

public void removeNode(UUID nodeId)

Removes node from affinity. This method is called when it is safe to remove left node from affinity mapping.

Specified by:

removeNode in interface AffinityFunction

Parameters:

nodeId - ID of node to remove.

writeExternal

public void writeExternal(ObjectOutput out)
                   throws IOException

Specified by:

writeExternal in interface Externalizable

Throws:

IOException

readExternal

public void readExternal(ObjectInput in)
                  throws IOException,
                         ClassNotFoundException

Specified by:

readExternal in interface Externalizable

Throws:

IOException

ClassNotFoundException

start

public void start()
           throws IgniteException

Starts grid component, called on grid start.

Specified by:

start in interface LifecycleAware

Throws:

IgniteException - If failed.

stop

public void stop()
          throws IgniteException

Stops grid component, called on grid shutdown.

Specified by:

stop in interface LifecycleAware

Throws:

IgniteException - If failed.

setIgnite

@IgniteInstanceResource
public void setIgnite(Ignite ignite)
                                       throws IgniteCheckedException

Injects the Ignite.

Parameters:

ignite - Ignite.

Throws:

IgniteCheckedException