org.apache.cassandra.dht
Interface IPartitioner<T extends Token>

All Known Implementing Classes:
CollatingOrderPreservingPartitioner, OrderPreservingPartitioner, RandomPartitioner

public interface IPartitioner<T extends Token>


Method Summary
 DecoratedKey<T> convertFromDiskFormat(java.lang.String key)
          Convert the on disk representation to a DecoratedKey object
 java.lang.String convertToDiskFormat(DecoratedKey<T> key)
          Convert the DecoratedKey to the on disk format used for this partitioner.
 DecoratedKey<T> decorateKey(java.lang.String key)
          Transform key to object representation of the on-disk format.
 T getMinimumToken()
           
 T getRandomToken()
           
 T getToken(java.lang.String key)
           
 Token.TokenFactory getTokenFactory()
           
 T midpoint(T left, T right)
          Calculate a Token representing the approximate "middle" of the given range.
 boolean preservesOrder()
           
 

Method Detail

convertFromDiskFormat

DecoratedKey<T> convertFromDiskFormat(java.lang.String key)
Convert the on disk representation to a DecoratedKey object

Parameters:
key - On disk representation
Returns:
DecoratedKey object

convertToDiskFormat

java.lang.String convertToDiskFormat(DecoratedKey<T> key)
Convert the DecoratedKey to the on disk format used for this partitioner.

Parameters:
key - The DecoratedKey in question
Returns:

decorateKey

DecoratedKey<T> decorateKey(java.lang.String key)
Transform key to object representation of the on-disk format.

Parameters:
key - the raw, client-facing key
Returns:
decorated version of key

midpoint

T midpoint(T left,
           T right)
Calculate a Token representing the approximate "middle" of the given range.

Returns:
The approximate midpoint between left and right.

getMinimumToken

T getMinimumToken()
Returns:
The minimum possible Token in the range that is being partitioned.

getToken

T getToken(java.lang.String 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

T getRandomToken()
Returns:
a randomly generated token

getTokenFactory

Token.TokenFactory getTokenFactory()

preservesOrder

boolean preservesOrder()
Returns:
True if the implementing class preserves key order in the Tokens it generates.


Copyright © 2010 The Apache Software Foundation