org.apache.cassandra.dht

Class AbstractByteOrderedPartitioner

java.lang.Object

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

org.apache.cassandra.dht.AbstractByteOrderedPartitioner

All Implemented Interfaces:

IPartitioner<BytesToken>

Direct Known Subclasses:

ByteOrderedPartitioner

public abstract class AbstractByteOrderedPartitioner
extends AbstractPartitioner<BytesToken>

Field Summary

Fields

Modifier and Type	Field and Description
static java.math.BigInteger	BYTE_MASK
static BytesToken	MINIMUM

Constructor Summary

Constructors

Constructor and Description
AbstractByteOrderedPartitioner()

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.
BytesToken	getMinimumToken()
BytesToken	getRandomToken()
abstract BytesToken	getToken(java.nio.ByteBuffer key)
Token.TokenFactory<byte[]>	getTokenFactory()
AbstractType<?>	getTokenValidator()
BytesToken	midpoint(Token ltoken, Token rtoken) 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

Field Detail

MINIMUM

public static final BytesToken MINIMUM

BYTE_MASK

public static final java.math.BigInteger BYTE_MASK

Constructor Detail

AbstractByteOrderedPartitioner

public AbstractByteOrderedPartitioner()

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 BytesToken midpoint(Token ltoken,
                  Token rtoken)

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 BytesToken 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.)

getRandomToken

public BytesToken getRandomToken()

Returns:

a randomly generated token

getTokenFactory

public Token.TokenFactory<byte[]> getTokenFactory()

preservesOrder

public boolean preservesOrder()

Returns:

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

getToken

public abstract BytesToken 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.)

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()