Package org.apache.cassandra.dht

Class LocalPartitioner

java.lang.Object

org.apache.cassandra.dht.LocalPartitioner

All Implemented Interfaces:

IPartitioner

public class LocalPartitioner
extends java.lang.Object
implements IPartitioner

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
class	LocalPartitioner.LocalToken

Constructor Summary

Constructors

Constructor	Description
LocalPartitioner(AbstractType<?> comparator)

Method Summary

Modifier and Type	Method	Description
DecoratedKey	decorateKey(java.nio.ByteBuffer key)	Transform key to object representation of the on-disk format.
java.util.Map<Token,java.lang.Float>	describeOwnership(java.util.List<Token> sortedTokens)	Calculate the deltas between tokens in the ring in order to compare relative sizes.
LocalPartitioner.LocalToken	getMinimumToken()
LocalPartitioner.LocalToken	getRandomToken()
LocalPartitioner.LocalToken	getRandomToken(java.util.Random random)
LocalPartitioner.LocalToken	getToken(java.nio.ByteBuffer key)
Token.TokenFactory	getTokenFactory()
AbstractType<?>	getTokenValidator()
Token	midpoint(Token left, Token right)	Calculate a Token representing the approximate "middle" of the given range.
AbstractType<?>	partitionOrdering()
boolean	preservesOrder()
Token	split(Token left, Token right, double ratioToLeft)	Calculate a Token which take approximate 0 <= ratioToLeft <= 1 ownership of the given range.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.cassandra.dht.IPartitioner

getMaximumToken, getMaxTokenSize, partitionOrdering, splitter

Constructor Detail

LocalPartitioner

public LocalPartitioner(AbstractType<?> comparator)

Method Detail

decorateKey

public DecoratedKey decorateKey(java.nio.ByteBuffer key)

Description copied from interface: IPartitioner

Transform key to object representation of the on-disk format.

Specified by:

decorateKey in interface IPartitioner

Parameters:

key - the raw, client-facing key

Returns:

decorated version of key

midpoint

public Token midpoint(Token left,
                      Token right)

Description copied from interface: IPartitioner

Calculate a Token representing the approximate "middle" of the given range.

Specified by:

midpoint in interface IPartitioner

Returns:

The approximate midpoint between left and right.

split

public Token split(Token left,
                   Token right,
                   double ratioToLeft)

Description copied from interface: IPartitioner

Calculate a Token which take approximate 0 <= ratioToLeft <= 1 ownership of the given range.

Specified by:

split in interface IPartitioner

getMinimumToken

public LocalPartitioner.LocalToken getMinimumToken()

Specified by:

getMinimumToken in interface IPartitioner

Returns:

A Token smaller than all others in the range that is being partitioned. Not legal to assign to a node or key. (But legal to use in range scans.)

getToken

public LocalPartitioner.LocalToken getToken(java.nio.ByteBuffer key)

Specified by:

getToken in interface IPartitioner

Returns:

a Token that can be used to route a given key (This is NOT a method to create a Token from its string representation; for that, use TokenFactory.fromString.)

getRandomToken

public LocalPartitioner.LocalToken getRandomToken()

Specified by:

getRandomToken in interface IPartitioner

Returns:

a randomly generated token

getRandomToken

public LocalPartitioner.LocalToken getRandomToken(java.util.Random random)

Specified by:

getRandomToken in interface IPartitioner

Parameters:

random - instance of Random to use when generating the token

Returns:

a randomly generated token

getTokenFactory

public Token.TokenFactory getTokenFactory()

Specified by:

getTokenFactory in interface IPartitioner

preservesOrder

public boolean preservesOrder()

Specified by:

preservesOrder in interface IPartitioner

Returns:

True if the implementing class preserves key order in the Tokens it generates.

describeOwnership

public java.util.Map<Token,java.lang.Float> describeOwnership(java.util.List<Token> sortedTokens)

Description copied from interface: IPartitioner

Calculate the deltas between tokens in the ring in order to compare relative sizes.

Specified by:

describeOwnership in interface IPartitioner

Parameters:

sortedTokens - a sorted List of Tokens

Returns:

the mapping from 'token' to 'percentage of the ring owned by that token'.

getTokenValidator

public AbstractType<?> getTokenValidator()

Specified by:

getTokenValidator in interface IPartitioner

partitionOrdering

public AbstractType<?> partitionOrdering()

Specified by:

partitionOrdering in interface IPartitioner