org.gridgain.grid.cache.affinity

Interface GridCacheAffinityKeyMapper

All Superinterfaces:

Serializable

All Known Implementing Classes:

GridCacheDefaultAffinityKeyMapper

public interface GridCacheAffinityKeyMapper
extends Serializable

Affinity mapper which maps cache key to an affinity key. Affinity key is a key which will be used to determine a node on which this key will be cached. Every cache key will first be passed through affinityKey(Object) method, and the returned value of this method will be given to GridCacheAffinityFunction implementation to find out key-to-node affinity.

The default implementation, which will be used if no explicit affinity mapper is specified in cache configuration, will first look for any field or method annotated with @GridCacheAffinityKeyMapped annotation. If such field or method is not found, then the cache key itself will be returned from affinityKey(Object) method (this means that all objects with the same cache key will always be routed to the same node). If such field or method is found, then the value of this field or method will be returned from affinityKey(Object) method. This allows to specify alternate affinity key, other than the cache key itself, whenever needed.

A custom (other than default) affinity mapper can be provided via GridCacheConfiguration.getAffinityMapper() configuration property.

For more information on affinity mapping and examples refer to GridCacheAffinityFunction and @GridCacheAffinityKeyMapped documentation.

See Also:

GridCacheAffinityFunction, GridCacheAffinityKeyMapped

Method Summary

Methods

Modifier and Type	Method and Description
Object	affinityKey(Object key) Maps passed in key to an alternate key which will be used for node affinity.
void	reset() Resets cache affinity mapper to its initial state.

Method Detail

affinityKey

Object affinityKey(Object key)

Maps passed in key to an alternate key which will be used for node affinity.

Parameters:

key - Key to map.

Returns:

Key to be used for node-to-affinity mapping (may be the same key as passed in).

reset

void reset()

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