org.apache.cassandra.dht

Class LocalPartitioner

java.lang.Object

org.apache.cassandra.dht.AbstractPartitioner<LocalToken>

org.apache.cassandra.dht.LocalPartitioner

All Implemented Interfaces:

IPartitioner<LocalToken>

public class LocalPartitioner
extends AbstractPartitioner<LocalToken>

Constructor Summary

Constructors

Constructor and Description
LocalPartitioner(AbstractType<?> comparator)

Method Summary

Methods

Modifier and Type	Method and 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.
LocalToken	getMinimumToken()
LocalToken	getRandomToken()
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.
boolean	preservesOrder()

Methods inherited from class org.apache.cassandra.dht.AbstractPartitioner

minValue

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

decorateKey

public DecoratedKey decorateKey(java.nio.ByteBuffer key)

Description copied from interface: IPartitioner

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

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.

Returns:

The approximate midpoint between left and right.

getMinimumToken

public LocalToken getMinimumToken()

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 LocalToken getToken(java.nio.ByteBuffer key)

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()

Returns:

a randomly generated token

getTokenFactory

public Token.TokenFactory getTokenFactory()

preservesOrder

public boolean preservesOrder()

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.

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()