org.apache.cassandra.dht
Class RandomPartitioner

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

All Implemented Interfaces:

IPartitioner<BigIntegerToken>

public class RandomPartitioner
extends java.lang.Object
implements IPartitioner<BigIntegerToken>

This class generates a BigIntegerToken using MD5 hash.

Field Summary

static BigIntegerToken	MINIMUM
static java.math.BigInteger	TWO

Constructor Summary

RandomPartitioner()

Method Summary

DecoratedKey<BigIntegerToken>	convertFromDiskFormat(java.lang.String key) Convert the on disk representation to a DecoratedKey object
java.lang.String	convertToDiskFormat(DecoratedKey<BigIntegerToken> key) Convert the DecoratedKey to the on disk format used for this partitioner.
DecoratedKey<BigIntegerToken>	decorateKey(java.lang.String key) Transform key to object representation of the on-disk format.
BigIntegerToken	getMinimumToken()
BigIntegerToken	getRandomToken()
BigIntegerToken	getToken(java.lang.String key)
Token.TokenFactory<java.math.BigInteger>	getTokenFactory()
BigIntegerToken	midpoint(BigIntegerToken ltoken, BigIntegerToken rtoken) 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

Field Detail

TWO

public static final java.math.BigInteger TWO

MINIMUM

public static final BigIntegerToken MINIMUM

Constructor Detail

RandomPartitioner

public RandomPartitioner()

Method Detail

decorateKey

public DecoratedKey<BigIntegerToken> decorateKey(java.lang.String key)

Description copied from interface: IPartitioner

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

Specified by:

decorateKey in interface IPartitioner<BigIntegerToken>

Parameters:

key - the raw, client-facing key

Returns:

decorated version of key

convertFromDiskFormat

public DecoratedKey<BigIntegerToken> convertFromDiskFormat(java.lang.String key)

Description copied from interface: IPartitioner

Convert the on disk representation to a DecoratedKey object

Specified by:

convertFromDiskFormat in interface IPartitioner<BigIntegerToken>

Parameters:

key - On disk representation

Returns:

DecoratedKey object

convertToDiskFormat

public java.lang.String convertToDiskFormat(DecoratedKey<BigIntegerToken> key)

Description copied from interface: IPartitioner

Convert the DecoratedKey to the on disk format used for this partitioner.

Specified by:

convertToDiskFormat in interface IPartitioner<BigIntegerToken>

Parameters:

key - The DecoratedKey in question

Returns:

midpoint

public BigIntegerToken midpoint(BigIntegerToken ltoken,
                                BigIntegerToken rtoken)

Description copied from interface: IPartitioner

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

Specified by:

midpoint in interface IPartitioner<BigIntegerToken>

Returns:

The approximate midpoint between left and right.

getMinimumToken

public BigIntegerToken getMinimumToken()

Specified by:

getMinimumToken in interface IPartitioner<BigIntegerToken>

Returns:

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

getRandomToken

public BigIntegerToken getRandomToken()

Specified by:

getRandomToken in interface IPartitioner<BigIntegerToken>

Returns:

a randomly generated token

getTokenFactory

public Token.TokenFactory<java.math.BigInteger> getTokenFactory()

Specified by:

getTokenFactory in interface IPartitioner<BigIntegerToken>

preservesOrder

public boolean preservesOrder()

Specified by:

preservesOrder in interface IPartitioner<BigIntegerToken>

Returns:

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

getToken

public BigIntegerToken getToken(java.lang.String key)

Specified by:

getToken in interface IPartitioner<BigIntegerToken>

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.)