org.infinispan.distribution
Class UnionConsistentHash

java.lang.Object
  org.infinispan.distribution.AbstractConsistentHash
      org.infinispan.distribution.UnionConsistentHash

All Implemented Interfaces:

ConsistentHash

public class UnionConsistentHash
extends AbstractConsistentHash

A delegating wrapper that locates keys by getting a union of locations reported by two other ConsistentHash implementations it delegates to.

Since:

4.0

Author:

Manik Surtani

Nested Class Summary

static class

UnionConsistentHash.Externalizer

Constructor Summary

UnionConsistentHash(ConsistentHash oldCH, ConsistentHash newCH)

Method Summary

List<Address>	getCaches() Should return a collection of cache addresses in the cluster.
int	getDistance(Address a1, Address a2) Calculates the logical distance between two addresses.
ConsistentHash	getNewConsistentHash()
ConsistentHash	getOldConsistentHash()
boolean	isAdjacent(Address a1, Address a2) Tests whether two addresses are logically next to each other in the hash space.
List<Address>	locate(Object key, int replCount) Locates a key, given a replication count (number of copies).
void	setCaches(List<Address> caches) Sets the collection of cache addresses in the cluster.

Methods inherited from class org.infinispan.distribution.AbstractConsistentHash

isKeyLocalToAddress, locateAll

Methods inherited from class java.lang.Object

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

Constructor Detail

UnionConsistentHash

public UnionConsistentHash(ConsistentHash oldCH,
                           ConsistentHash newCH)

Method Detail

setCaches

public void setCaches(List<Address> caches)

Description copied from interface: ConsistentHash

Sets the collection of cache addresses in the cluster. The implementation should store these internally and use these to locate keys.

Parameters:

caches - caches in cluster.

getCaches

public List<Address> getCaches()

Description copied from interface: ConsistentHash

Should return a collection of cache addresses in the cluster.

Returns:

collection of cache addresses

locate

public List<Address> locate(Object key,
                            int replCount)

Description copied from interface: ConsistentHash

Locates a key, given a replication count (number of copies).

Parameters:

key - key to locate

replCount - replication count (number of copies)

Returns:

a list of addresses where the key resides, where this list is a subset of the addresses set in ConsistentHash.setCaches(java.util.List). Should never be null, and should contain replCount elements or the max number of caches available, whichever is smaller.

getDistance

public int getDistance(Address a1,
                       Address a2)

Description copied from interface: ConsistentHash

Calculates the logical distance between two addresses. This distance is based on where the addresses lie in the hash space.

Parameters:

a1 - address to test

a2 - address to test

Returns:

the distance between the 2 nodes. Always a positive number, where the distance between a1 and itself is 0. The distance between a1 and the next adjacent node is 1 and teh distance between a1 and the previous adjacent node is caches.size() - 1. A -1 may be returned if either of the addresses do not exist.

isAdjacent

public boolean isAdjacent(Address a1,
                          Address a2)

Description copied from interface: ConsistentHash

Tests whether two addresses are logically next to each other in the hash space.

Parameters:

a1 - address to test

a2 - address to test

Returns:

true if adjacent, false if not

getNewConsistentHash

public ConsistentHash getNewConsistentHash()

getOldConsistentHash

public ConsistentHash getOldConsistentHash()