org.apache.cassandra.dht
Class LocalPartitioner

java.lang.Object
  org.apache.cassandra.dht.LocalPartitioner

All Implemented Interfaces:

IPartitioner<LocalToken>

public class LocalPartitioner
extends java.lang.Object
implements IPartitioner<LocalToken>

Constructor Summary

LocalPartitioner(AbstractType comparator)

Method Summary

DecoratedKey<LocalToken>	convertFromDiskFormat(java.nio.ByteBuffer key)
DecoratedKey<LocalToken>	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.
LocalToken	getMinimumToken()
LocalToken	getRandomToken()
LocalToken	getToken(java.nio.ByteBuffer key)
Token.TokenFactory	getTokenFactory()
Token	midpoint(Token left, Token right) Calculate a Token representing the approximate "middle" of the given range.
boolean	preservesOrder()

Methods inherited from class java.lang.Object

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

Constructor Detail

LocalPartitioner

public LocalPartitioner(AbstractType comparator)

Method Detail

convertFromDiskFormat

public DecoratedKey<LocalToken> convertFromDiskFormat(java.nio.ByteBuffer key)

Specified by:

convertFromDiskFormat in interface IPartitioner<LocalToken>

Parameters:

key - On disk representation

Returns:

DecoratedKey object

decorateKey

public DecoratedKey<LocalToken> 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<LocalToken>

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<LocalToken>

Returns:

The approximate midpoint between left and right.

getMinimumToken

public LocalToken getMinimumToken()

Specified by:

getMinimumToken in interface IPartitioner<LocalToken>

Returns:

The minimum possible Token in the range that is being partitioned.

getToken

public LocalToken getToken(java.nio.ByteBuffer key)

Specified by:

getToken in interface IPartitioner<LocalToken>

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 LocalToken getRandomToken()

Specified by:

getRandomToken in interface IPartitioner<LocalToken>

Returns:

a randomly generated token

getTokenFactory

public Token.TokenFactory getTokenFactory()

Specified by:

getTokenFactory in interface IPartitioner<LocalToken>

preservesOrder

public boolean preservesOrder()

Specified by:

preservesOrder in interface IPartitioner<LocalToken>

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<LocalToken>

Parameters:

sortedTokens - a sorted List of Tokens

Returns:

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