Package com.tangosol.net.partition

Interface KeyPartitioningStrategy

All Known Implementing Classes:

BroadKeyPartitioningStrategy, DefaultKeyPartitioningStrategy

public interface KeyPartitioningStrategy

A KeyPartitioningStrategy is a pluggable strategy for assigning keys to specific partitions.

Note: as of Coherence 3.6 the contract of the getKeyPartition method has changed and should take into consideration the service's key associator.

Since:

Coherence 3.0

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static interface	KeyPartitioningStrategy.PartitionAwareKey	PartitionAwareKey is a well-known interface that should be respected by KeyPartitioningStrategy implementations.

Method Summary

Modifier and Type	Method	Description
PartitionSet	getAssociatedPartitions(Object oKey)	Determine the set of partitions that all keys associated with the specified key are assigned to.
int	getKeyPartition(Object oKey)	Determine the partition to which a particular key should be assigned.
void	init(PartitionedService service)	Initialize the KeyPartitioningStrategy and bind it to the specified PartitionedService.

Method Details

init

void init(PartitionedService service)

Initialize the KeyPartitioningStrategy and bind it to the specified PartitionedService.

Parameters:

service - the PartitionedService that this strategy is being bound to

getKeyPartition

int getKeyPartition(Object oKey)

Determine the partition to which a particular key should be assigned.

In general, implementations are expected to respect the associations provided by the service's KeyAssociator in such a way that keys that return the same associated key would be assigned to the same partition. Furthermore, implementations are also expected to respect explicit partition-assignments dictated by the KeyPartitioningStrategy.PartitionAwareKey interface. Naturally, those two interfaces should not be combined for a given key.

The resulting partition must be in the range [0..N-1], where N is the value returned from PartitionedService.getPartitionCount().

Parameters:

oKey - a key in its Object form

Returns:

the partition ID that the specified key is assigned to

See Also:

• PartitionedService.getPartitionOwner(int)

getAssociatedPartitions

PartitionSet getAssociatedPartitions(Object oKey)

Determine the set of partitions that all keys associated with the specified key are assigned to. Most commonly, this method returns a partition set containing a single partition returned by the getKeyPartition method.

Parameters:

oKey - a key in its Object form

Returns:

the PartitionSet associated with the specified key

Since:

Coherence 3.6