org.infinispan.distribution.ch

Class ReplicatedConsistentHash

java.lang.Object

org.infinispan.distribution.ch.ReplicatedConsistentHash

All Implemented Interfaces:

ConsistentHash

public class ReplicatedConsistentHash
extends Object
implements ConsistentHash

Special implementation of ConsistentHash for replicated caches. The hash-space has several segments owned by all members and the primary ownership of each segment is evenly spread between members.

Since:

5.2

Author:

Dan Berindei, anistor@redhat.com

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ReplicatedConsistentHash.Externalizer

Constructor Summary

Constructors

Constructor and Description
ReplicatedConsistentHash(Hash hashFunction, List<Address> members, int[] primaryOwners)

Method Summary

Methods

Modifier and Type	Method and Description
Hash	getHashFunction()
List<Address>	getMembers() Should return the addresses of the nodes used to create this consistent hash.
int	getNumOwners()
int	getNumSegments()
String	getRoutingTableAsString() Returns a string containing all the segments and their associated addresses.
int	getSegment(Object key)
Set<Integer>	getSegmentsForOwner(Address owner) Returns the segments owned by a cache member.
boolean	isKeyLocalToNode(Address nodeAddress, Object key) Test to see whether a key is owned by a given node.
Set<Address>	locateAllOwners(Collection<Object> keys) The logical equivalent of calling ConsistentHash.locateOwners(java.lang.Object) multiple times for each key in the collection of keys and merging the results.
List<Address>	locateOwners(Object key) Finds all the owners of a key.
List<Address>	locateOwnersForSegment(int segmentId)
Address	locatePrimaryOwner(Object key) Should be equivalent to return the first element of ConsistentHash.locateOwners(java.lang.Object).
Address	locatePrimaryOwnerForSegment(int segmentId)
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

ReplicatedConsistentHash

public ReplicatedConsistentHash(Hash hashFunction,
                        List<Address> members,
                        int[] primaryOwners)

Method Detail

getNumSegments

public int getNumSegments()

Specified by:

getNumSegments in interface ConsistentHash

Returns:

The actual number of hash space segments. Note that it may not be the same as the number of segments passed in at creation time.

getNumOwners

public int getNumOwners()

Specified by:

getNumOwners in interface ConsistentHash

Returns:

The configured number of owners for each key. Note that {code @getOwners(key)} may return a different number of owners.

getMembers

public List<Address> getMembers()

Description copied from interface: ConsistentHash

Should return the addresses of the nodes used to create this consistent hash.

Specified by:

getMembers in interface ConsistentHash

Returns:

set of node addresses.

getHashFunction

public Hash getHashFunction()

Specified by:

getHashFunction in interface ConsistentHash

getSegment

public int getSegment(Object key)

Specified by:

getSegment in interface ConsistentHash

Returns:

The hash space segment that a key maps to.

locateOwnersForSegment

public List<Address> locateOwnersForSegment(int segmentId)

Specified by:

locateOwnersForSegment in interface ConsistentHash

Returns:

All the nodes that own a given hash space segment, first address is the primary owner. The returned list is unmodifiable.

locatePrimaryOwnerForSegment

public Address locatePrimaryOwnerForSegment(int segmentId)

Specified by:

locatePrimaryOwnerForSegment in interface ConsistentHash

Returns:

The primary owner of a given hash space segment. This is equivalent to locateOwnersForSegment(segmentId).get(0) but is more efficient

getSegmentsForOwner

public Set<Integer> getSegmentsForOwner(Address owner)

Description copied from interface: ConsistentHash

Returns the segments owned by a cache member.

Specified by:

getSegmentsForOwner in interface ConsistentHash

Parameters:

owner - the address of the member

Returns:

a non-nul set of segment IDs

getRoutingTableAsString

public String getRoutingTableAsString()

Description copied from interface: ConsistentHash

Returns a string containing all the segments and their associated addresses.

Specified by:

getRoutingTableAsString in interface ConsistentHash

locatePrimaryOwner

public Address locatePrimaryOwner(Object key)

Description copied from interface: ConsistentHash

Should be equivalent to return the first element of ConsistentHash.locateOwners(java.lang.Object). Useful as a performance optimization, as this is a frequently needed information.

Specified by:

locatePrimaryOwner in interface ConsistentHash

Parameters:

key - key to locate

Returns:

the address of the owner

locateOwners

public List<Address> locateOwners(Object key)

Description copied from interface: ConsistentHash

Finds all the owners of a key. The first element in the returned list is the primary owner.

Specified by:

locateOwners in interface ConsistentHash

Parameters:

key - key to locate

Returns:

An unmodifiable list of addresses where the key resides. Will never be null, and it will always have at least 1 element.

locateAllOwners

public Set<Address> locateAllOwners(Collection<Object> keys)

Description copied from interface: ConsistentHash

The logical equivalent of calling ConsistentHash.locateOwners(java.lang.Object) multiple times for each key in the collection of keys and merging the results. Implementations may be optimised for such a bulk lookup.

Specified by:

locateAllOwners in interface ConsistentHash

Parameters:

keys - keys to locate.

Returns:

set of nodes that own at least one of the keys.

isKeyLocalToNode

public boolean isKeyLocalToNode(Address nodeAddress,
                       Object key)

Description copied from interface: ConsistentHash

Test to see whether a key is owned by a given node.

Specified by:

isKeyLocalToNode in interface ConsistentHash

Parameters:

nodeAddress - address of the node to test

key - key to test

Returns:

true if the key is mapped to the address; false otherwise

toString

public String toString()

Overrides:

toString in class Object