org.infinispan.distribution.ch.impl

Class ReplicatedConsistentHash

java.lang.Object

org.infinispan.distribution.ch.impl.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
static class	ReplicatedConsistentHash.RangeSet

Constructor Summary

Constructors

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

Method Summary

Modifier and Type	Method and Description
boolean	equals(Object obj)
Hash	getHashFunction()
List<Address>	getMembers() Should return the addresses of the nodes used to create this consistent hash.
int	getNumOwners()
int	getNumSegments()
Set<Integer>	getPrimarySegmentsForOwner(Address owner) Returns the segments that this cache member is the primary owner for.
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.
int	hashCode()
boolean	isKeyLocalToNode(Address nodeAddress, Object key) Test to see whether a key is owned by a given node.
boolean	isReplicated()
boolean	isSegmentLocalToNode(Address nodeAddress, int segmentId) Check if a segment is local to a given member.
Set<Address>	locateAllOwners(Collection<Object> keys)
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)
void	toScopedState(ScopedPersistentState state) Writes this ConsistentHash to the specified scoped state.
String	toString()
ReplicatedConsistentHash	union(ReplicatedConsistentHash ch2)

Methods inherited from class java.lang.Object

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

Constructor Detail

ReplicatedConsistentHash

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

Method Detail

union

public ReplicatedConsistentHash union(ReplicatedConsistentHash ch2)

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-null set of segment IDs, may or may not be unmodifiable, which shouldn't be modified by caller

getPrimarySegmentsForOwner

public Set<Integer> getPrimarySegmentsForOwner(Address owner)

Description copied from interface: ConsistentHash

Returns the segments that this cache member is the primary owner for.

Specified by:

getPrimarySegmentsForOwner in interface ConsistentHash

Parameters:

owner - the address of the member

Returns:

a non-null set of segment IDs, may or may not be unmodifiable, which shouldn't be modified by caller

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)

Specified by:

locateAllOwners in interface ConsistentHash

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

isSegmentLocalToNode

public boolean isSegmentLocalToNode(Address nodeAddress,
                                    int segmentId)

Description copied from interface: ConsistentHash

Check if a segment is local to a given member.

Implementation note: normally key-based method are implemented based on segment-based methods. Here, however, we need a default implementation for the segment-based method for backwards-compatibility reasons.

Specified by:

isSegmentLocalToNode in interface ConsistentHash

isReplicated

public boolean isReplicated()

Specified by:

isReplicated in interface ConsistentHash

Returns:

true if every member owns every segment. This allows callers to skip computing the segment of a key in some cases.

toScopedState

public void toScopedState(ScopedPersistentState state)

Description copied from interface: ConsistentHash

Writes this ConsistentHash to the specified scoped state.

Specified by:

toScopedState in interface ConsistentHash

Parameters:

state - the state to which this ConsistentHash will be written

toString

public String toString()

Overrides:

toString in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object obj)

Overrides:

equals in class Object