org.apache.cassandra.dht

Class Splitter

java.lang.Object

org.apache.cassandra.dht.Splitter

public abstract class Splitter
extends java.lang.Object

Partition splitter.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Splitter.WeightedRange

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Splitter(IPartitioner partitioner)

Method Summary

Modifier and Type	Method and Description
protected java.math.BigInteger	elapsedTokens(Token token, Range<Token> range) Computes the number of elapsed tokens from the range start until this token
double	positionInRange(Token token, Range<Token> range) Computes the normalized position of this token relative to this range
java.util.Set<Range<Token>>	split(java.util.Collection<Range<Token>> ranges, int parts) Splits the specified token ranges in at least parts subranges.
java.util.List<Token>	splitOwnedRanges(int parts, java.util.List<Splitter.WeightedRange> weightedRanges, boolean dontSplitRanges)
protected abstract Token	tokenForValue(java.math.BigInteger value)
protected java.math.BigInteger	tokensInRange(Range<Token> range)
protected abstract java.math.BigInteger	valueForToken(Token token)

Methods inherited from class java.lang.Object

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

Constructor Detail

Splitter

protected Splitter(IPartitioner partitioner)

Method Detail

tokenForValue

protected abstract Token tokenForValue(java.math.BigInteger value)

valueForToken

protected abstract java.math.BigInteger valueForToken(Token token)

tokensInRange

protected java.math.BigInteger tokensInRange(Range<Token> range)

elapsedTokens

protected java.math.BigInteger elapsedTokens(Token token,
                                             Range<Token> range)

Computes the number of elapsed tokens from the range start until this token

Returns:

the number of tokens from the range start to the token

positionInRange

public double positionInRange(Token token,
                              Range<Token> range)

Computes the normalized position of this token relative to this range

Returns:

A number between 0.0 and 1.0 representing this token's position in this range or -1.0 if this range doesn't contain this token.

splitOwnedRanges

public java.util.List<Token> splitOwnedRanges(int parts,
                                              java.util.List<Splitter.WeightedRange> weightedRanges,
                                              boolean dontSplitRanges)

split

public java.util.Set<Range<Token>> split(java.util.Collection<Range<Token>> ranges,
                                         int parts)

Splits the specified token ranges in at least parts subranges.

Each returned subrange will be contained in exactly one of the specified ranges.

Parameters:

ranges - a collection of token ranges to be split

parts - the minimum number of returned ranges

Returns:

at least minParts token ranges covering ranges