org.infinispan.distribution.ch.impl

Class ReplicatedConsistentHashFactory

java.lang.Object

org.infinispan.distribution.ch.impl.ReplicatedConsistentHashFactory

All Implemented Interfaces:

ConsistentHashFactory<ReplicatedConsistentHash>

public class ReplicatedConsistentHashFactory
extends Object
implements ConsistentHashFactory<ReplicatedConsistentHash>

Factory for ReplicatedConsistentHash.

Since:

5.2

Author:

Dan Berindei, anistor@redhat.com

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ReplicatedConsistentHashFactory.Externalizer

Constructor Summary

Constructors

Constructor and Description
ReplicatedConsistentHashFactory()

Method Summary

Modifier and Type	Method and Description
ReplicatedConsistentHash	create(int numOwners, int numSegments, List<Address> members, Map<Address,Float> capacityFactors) Create a new consistent hash instance.
boolean	equals(Object other)
ReplicatedConsistentHash	fromPersistentState(ScopedPersistentState state) Recreates a ConsistentHash from a previously stored persistent state.
int	hashCode()
ReplicatedConsistentHash	rebalance(ReplicatedConsistentHash baseCH) Create a new consistent hash instance, based on an existing instance, but balanced according to the implementation's rules.
ReplicatedConsistentHash	union(ReplicatedConsistentHash ch1, ReplicatedConsistentHash ch2) Creates a union of two compatible ConsistentHashes (use the same hashing function and have the same configuration parameters).
ReplicatedConsistentHash	updateMembers(ReplicatedConsistentHash baseCH, List<Address> newMembers, Map<Address,Float> actualCapacityFactors) Updates an existing consistent hash instance to remove owners that are not in the newMembers list.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.infinispan.distribution.ch.ConsistentHashFactory

create

Constructor Detail

ReplicatedConsistentHashFactory

public ReplicatedConsistentHashFactory()

Method Detail

create

public ReplicatedConsistentHash create(int numOwners,
                                       int numSegments,
                                       List<Address> members,
                                       Map<Address,Float> capacityFactors)

Description copied from interface: ConsistentHashFactory

Create a new consistent hash instance. The consistent hash will be balanced.

Specified by:

create in interface ConsistentHashFactory<ReplicatedConsistentHash>

Parameters:

numOwners - The ideal number of owners for each key. The created consistent hash can have more or less owners, but each key will have at least one owner.

numSegments - Number of hash-space segments. The implementation may round up the number of segments for performance, or may ignore the parameter altogether.

members - A list of addresses representing the new cache members.

capacityFactors - The capacity factor of each member. Determines the relative capacity of each node compared to the others. The implementation may ignore this parameter. If null, all the members are assumed to have a capacity factor of 1.

fromPersistentState

public ReplicatedConsistentHash fromPersistentState(ScopedPersistentState state)

Description copied from interface: ConsistentHashFactory

Recreates a ConsistentHash from a previously stored persistent state. The returned ConsistentHash will not have proper addresses, but PersistentUUIDs instead so they will need to be replaced

Specified by:

fromPersistentState in interface ConsistentHashFactory<ReplicatedConsistentHash>

Parameters:

state - the state to restore

updateMembers

public ReplicatedConsistentHash updateMembers(ReplicatedConsistentHash baseCH,
                                              List<Address> newMembers,
                                              Map<Address,Float> actualCapacityFactors)

Description copied from interface: ConsistentHashFactory

Updates an existing consistent hash instance to remove owners that are not in the newMembers list.

If a segment has at least one owner in newMembers, this method will not add another owner. This guarantees that the new consistent hash can be used immediately, without transferring any state.

If a segment has no owners in newMembers and the ConsistentHash implementation (e.g. DefaultConsistentHash) requires at least one owner for each segment, this method may add one or more owners for that segment. Since the data in that segment was lost, the new consistent hash can still be used without transferring state.

Specified by:

updateMembers in interface ConsistentHashFactory<ReplicatedConsistentHash>

Parameters:

baseCH - An existing consistent hash instance, should not be null

newMembers - A list of addresses representing the new cache members.

actualCapacityFactors - The capacity factor of each member. Determines the relative capacity of each node compared to the others. The implementation may ignore this parameter. If null, all the members are assumed to have a capacity factor of 1.

Returns:

A new ConsistentHash instance, or baseCH if the existing instance does not need any changes.

rebalance

public ReplicatedConsistentHash rebalance(ReplicatedConsistentHash baseCH)

Description copied from interface: ConsistentHashFactory

Create a new consistent hash instance, based on an existing instance, but balanced according to the implementation's rules.

Specified by:

rebalance in interface ConsistentHashFactory<ReplicatedConsistentHash>

Parameters:

baseCH - An existing consistent hash instance, should not be null

Returns:

A new ConsistentHash instance, or baseCH if the existing instance does not need any changes.

union

public ReplicatedConsistentHash union(ReplicatedConsistentHash ch1,
                                      ReplicatedConsistentHash ch2)

Description copied from interface: ConsistentHashFactory

Creates a union of two compatible ConsistentHashes (use the same hashing function and have the same configuration parameters).

The owners of a segment s in union(ch1, ch2) will include both the owners of s in ch1 and the owners of s in ch2, so a cache can switch from using union(ch1, ch2) to using ch2 without transferring any state.

Specified by:

union in interface ConsistentHashFactory<ReplicatedConsistentHash>

equals

public boolean equals(Object other)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object